Citation for XAO v1 by Xenbase: Segerdell E, Bowes JB, Pollet N, Vize PD; BMC Dev Biol 2008 8:92; PMID:18817563.
Citation for XAO v3 by Xenbase: Segerdell E, Ponferrada VG, James-Zorn C, Burns KA, Fortriede JD, Dahdul WM, Vize PD, Zorn AM; J Biomed Semantics 2013 4(1):31; PMID:24139024.
Supported by NIH R01 HD045776 and NICHD P41 HD064556.
Anatomical structure/expression stops being viable, obvious or of utility during this developmental stage.
Anatomical structure/expression begins being viable, obvious or of utility during this developmental stage.
Entity that is either an individual member of Xenopus or constitutes the structural organization of an individual member Xenopus.
Primary germ layer that is the outer of the embryo's germ layers and gives rise to epidermis and neural tissue.
Surface structure that has an important role in tadpole locomotion. It starts to develop along the trunk and tail of the embryo at the tail bud stage and continues to grow until the start of metamorphosis when it begins to regress. It consists of flattened epidermal cells elevated into a keel-like structure by a supporting core of mesenchyme and extracellular matrix.
Part of the fin consisting of flattened epidermal cells elevated into a keel-like structure.
Part of the fin consisting of a supporting core of mesenchyme and extracellular matrix.
A thick plate of cells derived from the neural ectoderm in the head region of the embryo that develops into the olfactory region of the nasal cavity.
The saccular invagination of ectoderm from which the vertebrate inner ear develops.
A surface structure consisting of a set of membranes that cover and protect the eye.
Transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina.
Sensory membrane that lines the posterior chamber of the eye and functions as the immediate instrument of vision by receiving the image formed by the lens and converting it into chemical and nervous signals which reach the brain by way of the optic nerve.
Organ that is a component of the central nervous system and is responsible for the coordination and control of bodily activities and the interpretation of information from the senses. It appears when the neural tube segregates in forebrain, midbrain, and hindbrain at NF stage 22. The general pattern of the brain has been mainly established at NF stage 28. Yolky material is consumed and the fibre tracts and later the commissures develop. In general all of its parts are well developed at NF stage 53 and later development consists mainly of growth and some further cytological differentiation. In the period of metamorphosis only topographical changes take place.
The part of the brain that is the anterior of its three primary divisions and that includes the telencephalon and diencephalon.
Part of the forebrain consisting of paired olfactory bulbs and cerebral hemispheres.
The more posterior and ventral of two forebrain neuromeres, the other being the telencephalon; major derivatives are the eye vescile, the brain pretectal region, the thalamus, hypothalamus, and epithalamus (including the habenula and epiphysis).
Middle part of the brain composed of the optic tectum and penducular region.
The part of the brain that is the posterior of its three primary divisions.
The part of the brain that is the morphological boundary between the midbrain and hindbrain and that is the location of an organizing center which patterns the midbrain and hindbrain primordia of the neural plate.
An endocrine gland, located ventral to the diencephalon, that secretes hormones that regulate many other glands.
Portion of tissue that is the precursor to the gonads.
Elongated, approximately cylindrical part of the central nervous system that lies in the vertebral canal and from which the spinal nerves emerge.
Proliferative region that is part of the ventricular system of the brain.
Organizing center located at the dorsal midline of the neural tube that influences the development of the nervous system, controlling the specification and differentiation of dorsal neuronal cell types.
Surface structure that consists of the external membranous integument of the animal.
The most anterior of the migrating cranial neural crest streams, running along the posterior edge of the eye primordium, and in later stages, below the eye and to the border of the cement gland. The mandibular stream is the first to initiate CNC cell migration.
The second most anterior of the migrating cranial neural crests streams, it lays between the mandibular and anterior branchial crest streams.
The most posterior segments of the population of migratory cells of the cranial neural crest, contributing to the branchial arches 3 and 4. Branchial crest cells migrate in two distinct streams referred to as the anterior and posterior branchial crest.
The outer epithelial layer of the external integument of the body that is derived from the embryonic epiblast.
The outermost layer of the epidermis, the multilayered epithelium derived from the ectoderm.
The membrane enveloping the egg or oocyte, lying immediately outside the plasmalemma. It is formed while the oocyte is in the ovary and it separates from the egg to form the fertilization membrane.
Cell type that has motile cilia and populates the skin of the embryo, arranged in the surface layer of the non-neural ectoderm in an ordered distribution.
An anterior thickening of the sensorial layer of ectoderm, just above the cement gland. The hypophyseal layer separates from the stomodeal layer at NF stage 29 and 30, and when contacted by a protrusion of the foregut, the stomodeal layer will rupture to form the mouth opening at NF stage 39 and 40.
A simple mucus-secreting structure that is positioned at the front of the embryo, attaches the newly hatched embryo to a support before the hatchling can swim well or feed, and marks the anterior-most dorsal ectoderm.
A Y-shaped array of unicelluar glands on the top of the head, the open end of which faces anteriorly, that secrete an enzyme that dissolves or weakens the egg jelly and facilitates hatching. Presumptive cells of the hatching gland are present by the end of gastrualtion (NF stage 12.5) and differentiated cells start to form after neurulation is complete (NF stage 21).
Cell resulting from the fusion of male and female gametes at fertilization.
Sensorial layer of blastocoel roof ectoderm.
Superficial layer of blastocoel roof ectoderm.
The anterior-most third of the embryo, formed from the development of the head outgrowth at NF stage 21.
A distinct layer of the epidermal cells beneath the outermost layer of epidermis, the multilayered epithelium derived from the ectoderm.
Embryonic ectoderm that gives rise to nervous tissue.
Superficial neuroectoderm layer consisting of horizontally flattened, pigmented cells.
Deep neuroectoderm layer consisting of densely packed, cylindrical, unpigmented cells.
The portion of neural plate anterior to the mid-hindbrain junction.
The portion of neural plate posterior to the mid-hindbrain junction.
Region of the neural plate overlying the notochord.
A group of ectoderm cells that delaminate from the area between the neuroectoderm/non-neural ectoderm domains. They undergo epithelial-to-mesenchymal tranformation (EMT) and migrate to give several different lineages of adult cells. Originating from different positions along the anterior-posterior axis, they develop into various tissues. These regions of neural crest can be divided into five main functional domains, which include the cranial, trunk, vagal and sacral neural crest, and cardiac neural crest. Neural crest cells are considered multipotent, and as they have the limited capacity for self renewal, they are regarded as stem cell-like.
The thickening of the epithelial layer of the ectoderm, with corresponding dark pigmentation, on the anterior dorso-ventral surface of the embryo.
Primary germ layer that is the middle of the embryo's germ layers.
Principal unpaired, median artery of the trunk, extending into the tail as the caudal artery.
The paired main vein, departing from the sinus venous, the fused heart primordium, it runs posteriorly down length of the embryo.
The anatomical region of the body posterior to the head and anterior to the tail.
A longitudinal flexible rod of cells that in the embryo forms the supporting axis of the body. It degenerates, beginning anteriorly, at NF stage 46. Its posterior portion is greatly reduced by NF stage 55 and the entire structure is gone by NF stage 65.
Transient structure that lies immediately ventral to the notochord in the embryo, likely required for the formation of the dorsal aorta. A slight depression marks the future hypochord at NF stage 20 and its segregation from the dorsal endoderm begins at NF stage 24. It progresses from anterior to posterior and is complete by NF stage 28. At NF stage 32 it is present as a dorso-laterally flattened ribbon of yolk-laden cells. It degenerates by apoptosis and by NF stage 43 is no longer detectable as a distinct structure in the trunk region of the tadpole. The most posterior hypochord persists and begins to ossify, fusing with the coccyx to form the urostyle in the pelvic girdle around NF stage 63.
Unsegmented field of paraxial mesoderm present posterior to the most recently formed somite pair, from which somites will form.
Any of the approximately 45 bilaterally paired blocks of mesoderm cells, lying on either side of the notochord and neural tube, and forming sequentially starting at the head during development of the embryo. Together they give rise to the axial skeleton (from the sclerotome), associated musculature (from the myotome), and dermis (from the dermatome).
Any of the ciliated tubules that collect the glomeral filtrate, passing it through to the pronephric tubules.
Duct that drains urine from the pronephros and connects it to the cloaca. It is thought that the pronephric duct may play a key role in the induction of the mesonephric (adult) kidney. The most anterior part of the pronephric duct shows distinct gene expression patterns and is sometimes referred to as DT2.
A myogenic muscular organ found in the cardiovascular system. It is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions. It is composed of cardiac muscle, which is an involuntary striated muscle tissue found only in this organ, and connective tissue. It is ultimately composed of three chambers (two atria and one ventricle), occupying a ventral position within the chest of the mature tadpole/frog.
Cardiac muscle constituting the middle layer of the heart.
Part of the heart composed of thin serous membrane and endothelial tissue, that lines the interior of the heart.
Region located on the ventral surface of the developing embryo that is a site of hematopoiesis and that is analogous to the yolk sac blood islands of higher vertebrates.
Region of intermediate pigmentation between the pigmented animal hemisphere and the unpigmented vegetal hemisphere of the egg.
Embryonic tissue region that will make the ventral mesoderm.
Region of the marginal zone extending from the ventral to lateral surface.
Region of the marginal zone extending from the dorsal to lateral surface.
Marginal zone that is a key embryonic tissue region of the early gastrula stage embryo and that houses the Spemann-Mangold organizer.
Portion of the marginal zone of the embryo that turns inside the embryo during involution.
involuting marginal zone mesenchymal layer
Deep layers of the IMZ consisting of prospective migrating mesodermal cells (which will migrate into the interior and form the leading edge of the mesodermal mantle) and prospective converging and extending mesoderm.
involuting marginal zone epithelial layer
Layer of prospective endoderm in the IMZ that will form the roof of the archenteron.
Cell type that is first to migrate inwards at the blastopore during gastrulation.
The edge of the blastopore. Local invagination is caused by narrowing of bottle cells at the exterior edge of the blastula.
Mesodermal structure that lies anterior to the notochord and gives rise to head mesoderm.
The region from which the forelimb develops, first recognizable at NF stage 48, and distinct by NF stage 49.
The region from which the hindlimb develops, first recognizable as a slight concentration of mesenchymal cells dorsal and lateral to the anal tube at NF stage 43. The epidermal layers thicken dramatically through to NF stage 48, and become vascularised by NF stage 49.
Embryonic structure that develops around the closed blastopore.
Dorsal mesoderm that has grown and curled inward during gastrulation.
Ventral mesoderm that has grown and curled inward during gastrulation.
Mesoderm layer between somite and lateral plate. All components of the pronephric kidney arise from this.
The region at the periphery of the retina where retinal stem cells are located. It is spatially ordered with respect to cellular development and differentiation, with the youngest and least-determined stem cells closest to the periphery, the proliferative retinoblasts in the middle, and postmitotic cells at the central edge.
The anatomical region of the body posterior to the tail.
Dorsal part of the blastopore lip, which forms as a result of the contraction of bottle cells.
Ventral part of the blastopore lip, which forms as a result of the contraction of bottle cells.
Primary germ layer that lies remote from the surface of the embryo and gives rise to internal tissues such as gut.
The cavity of the gastrula forming a primitive gut. At NF stage 20-21 its wide canal becomes dorso-ventrally compressed and narrowed in the future trunk region so that a subdivision into a foregut, a midgut and a hindgut with protruding endodermal mass becomes manifest.
The layer of cells forming the ventral surface of the archenteron space of the embryo.
The layer of cells forming the dorsal surface of the archenteron space of the embryo.
Sensory system that has as it parts the sense organs that detect vibrations carried through water, develops during late tailbud stage, and persists in the adult bearing elaborate dorsal and ventral components. It develops from a specialized series of dorsolateral ectodermal placodes named lateral line placodes.
One of a series of bony or cartilaginous arches that develop in the walls of the mouth cavity and pharynx of the embryo.
The first of the series of bony or cartilaginous arches that develop in the walls of the mouth cavity and pharynx of the embryo.
The second of the series of bony or cartilaginous arches that develop in the walls of the mouth cavity and pharynx of the embryo.
Structures that develop from the pharyngeal arches. Pharyngeal arches are anlage for a multitude of structures. Each pharyngeal arch has a cartilaginous stick, a muscle component which differentiates from the cartilaginous tissue, an artery, and a cranial nerve. Each of these is surrounded by mesenchyme. Arches do not develop simultaneously, but instead possess a staggered development.
Anatomical system that has as its parts the heart and blood vessels.
An out-pocket of thickened ventral foregut epithelium adjacent to the developing heart. Its anterior portion gives rise to the liver and intrahepatic biliary tree, while the posterior portion forms the gall bladder and extrahepatic bile duct.
First of the pharyngeal (endodermal) evaginations between the visceral arches from which the Eustachian tube is derived; pouches 2-4 open as gill slits.
Middle subdivision of the digestive tract. The midgut is the portion of the embryo from which most of the intestines develop. After it bends around the superior mesenteric artery, it is often referred to as the "midgut loop". It comprises the portion of the alimentary canal from the end of the foregut at the opening of the bile duct to the hindgut, about two-thirds of the way through the transverse colon.
Posterior subdivision of the digestive tract. The posterior part of the alimentary canal, including the large intestine and cloaca.
The space enclosed by the walls of the pharynx.
Tissue that is a temporary extension of the embryonic gut caudal to the cloaca.
Rapidly proliferating mass of cells at the caudal extremity of the embryo. Its formation is reflected in a caudal carving of the posterior portion of the archenteric canal at NF stage 22. With its further outgrowth, the postanal gut primordium becomes stretched. Its lumen is in broad communication with the hindgut at NF stage 25.
The anterior limit of the neurenteric canal, which connects the post-anal gut with the central canal of the spinal chord. It is formed from a population of cells derived from the dorsal lip of the late gastrula, and has been shown to be important in tail development.
Structure formed by the ventral movement of the proctodeum anlage, which results in the shifting of the circumblastoral collar lateral walls to the posterior end of the embryo.
Portion of tissue that consists of the precursors of the pronephric glomus or glomerulus; derived from the medial portion of the pronephric intermediate mesoderm.
Cell type that is involved in the reproduction of the organism.
Anatomical entity that comprises the animal in the early stages of growth and differentiation that are characterized by cleavage, the laying down of fundamental tissues, and the formation of primitive organs and organ systems.
Any of the tubular branching vessels that carry blood from the heart through the body.
Any of the tubular branching vessels that carry blood from the capillaries toward the heart.
Any of the smallest blood vessels connecting arterioles with venules.
Anatomical system that has as its parts the organs involved in breathing in respiration (breathing).
An elongated tube that carries air to and from the lungs.
Either of two organs that allow gas exchange absorbing oxygen from inhaled air and releasing carbon dioxide with exhaled air.
The primary respiration organ in some species of tadpoles, whose function is the extraction of oxygen from water and the excretion of carbon dioxide. The microscopic structure of a gill is such that it presents a very large surface area to the external environment. Gills usually consist of thin filaments of tissue, branches, or slender tufted processes which have a highly folded surface to increase surface area. A high surface area is crucial for effective gas exchange.
A passage of airway in the respiratory tract that conducts air into the lungs.
Anatomical system that consists of the blood and blood forming tissues.
Flexible tissue found in the hollow interior of bones. In adults, marrow in large bones produces new blood cells.
The fluid that circulates in the heart, arteries, capillaries, and veins carrying nourishment and oxygen to and bringing away waste products from all parts of the animal.
Anatomical system that has as its parts the organs devoted to the ingestion, digestion, and assimilation of food and the discharge of residual wastes.
The cavity of the mouth, bounded by the jaw bones and associated structures.
Tube that connects the pharynx to the stomach. At NF stage 57 it is a straight tube, round in cross section, and starting from the pharynx runs backward along the dorsal side of the abdominal cavity. Its lining consists of a columnar glandular epithelium with mucus secreting cells. It is thrown into longitudinal folds.
Internal organ that is the dilated portion of the alimentary tract situated between the esophagus and the beginning of the duodenum. It produces gastric juices involved in the breakdown of food.
Portion of the alimentary canal bounded anteriorly by the pyloric sphincter and posteriorly by the cloacal sphincter.
A part of the alimentary system and principal organ of digestion, comprising the duodenum and ileum and characterized by longitudinal folds. In the tadpole it is a long simple tube with a single layer of cuboidal epithelial cells.
A short, wide tube that is part of the alimentary system and comprises the colon and rectum and empties into the cloaca. It lacks longitudinal folds characteristic of the small intestine. It absorbs water and salts from the gut lumen.
Anatomical system comprising the liver, gall bladder, and associated ducts.
Organ that secretes bile and participates in formation of certain blood proteins. The liver is the largest internal organ, primarily consisting of hepatocytes, and has a wider variety of functions than any other organs in the body. The hepatocyte is a polarized epithelial cell that exhibits both endocrine and exocrine properties. The biliary epithelial cells (cholangiocytes), sinusoidal endothelial cells, hepatic stellate cells (Ito cells), Kupffer cells, and pit cells (liver-specific natural killer cells) represent the majority of non-hepatocyte cell types in the liver. During embryogenesis, the liver is generated in the ventral foregut endoderm.
Duct that carries bile from the liver to the small intestine.
A small organ of the alimentary system that aids mainly in fat digestion, and concentrates bile that is produced by the liver.
Internal gland organ with distinct tissues with different endocrine and exocrine functions. Its rudiment has three parts, one dorsal and two ventral primordia. The ventral can be first detected at NF stage 37/38. The dorsal is clearly segregated from the duodenal wall by NF stage 39. At NF stage 40 the right and left primordia have fused just above the gastro-duodenal vein. At NF stage 42 blood vessels penetrate into the crevices between the pancreatic acini making them more conspicuous.
Pancreatic tissue composed of acinar epithelial cells and ductal epithelium that manufacture the proteolytic enzymes and bicarbonate required for digestion.
A double layer of tissue composed of peritoneum that attaches the visceral organs to the body wall.
Serous membrane that forms the lining of the abdominal cavity or the coelom. It covers most of the intra-abdominal organs, supports the abdominal organs, and serves as a conduit for their blood and lymph vessels and nerves. It is composed of a layer of mesothelium.
Anatomical system that has as its parts the organs concerned with the production and excretion of urine and those concerned with reproduction.
Organ that is the definitive adult kidney. It replaces the earlier pronephros, which degenerates as the mesonephros becomes functional in feeding stage tadpoles.
Anatomical system that has as its parts the organs concerned with reproduction.
Anatomical system that has as its parts the organs concerned with the production and excretion of urine.
Anatomical structure consisting of a long narrow duct that carries urine from the kidney to the urinary bladder.
A tuft of capillaries found in a Bowman's capsule in which waste products are filtered from the blood and urine formation is initiated.
Any of the excretory units of the mesonephros, which connect to the mesonephric collecting duct.
Duct that connects to the mesonephric nephrons and collects filtrate.
Anatomical structure consisting of a tube carries urine from the urinary bladder to the outside of the body.
The organ that collects urine excreted by the kidneys before disposal by urination.
Anatomical system comprising the organs of the male reproductive system.
Anatomical system comprising the organs of the female reproductive system.
Reproductive organ that produces and releases sperm.
Anatomical system that consists of the glands and parts of glands that produce endocrine secretions and help to integrate and control bodily metabolic activity.
Structure that is made up of islet cells that produce insulin, glucagon, and somatostatin.
An unpaired glandular organ subdivision attached on the midline near the posterior and habenular commissures of the epithalamus.
A two-lobed endocrine gland, located next to the trachea, and producing various hormones, such as triiodothyronine and calcitonin.
Anatomical structure of largely lymphoid tissue that functions in cell-mediated immunity by being the site where T cells develop.
Either of a pair of complex endocrine organs near the anterior medial border of the kidney consisting of a mesodermal cortex that produces glucocorticoid, mineralocorticoid, and androgenic hormones and an ectodermal medulla that produces epinephrine and norepinephrine.
Situated along the perimeter of the adrenal gland, the adrenal cortex mediates the stress response through the production of mineralocorticoids and glucocorticoids, including aldosterone and cortisol respectively. It is also a secondary site of androgen synthesis. The perimeter region of the adrenal gland, the site of steroid synthesis.
Part of the adrenal gland, located at the center of the gland and surrounded by the adrenal cortex. It is the innermost part of the adrenal gland, consisting of cells that secrete epinephrine, norepinephrine, and a small amount of dopamine in response to stimulation by sympathetic preganglionic neurons. Composed mainly of hormone-producing chromaffin cells, it is the principal site of the conversion of the amino acid tyrosine into the catecholamines adrenaline (epinephrine), noradrenaline (norepinephrine), and dopamine.
An organ specialized for secretion of parathyroid hormone. It controls the amount of calcium in the blood and within the bones.
Anatomical system that provides locomotion and physical support to the organism.
The hard form of connective tissue that constitutes the majority of the skeleton.
A type of dense connective tissue that is composed of specialized cells, chondrocytes, that produce a large amount of extracellular matrix.
Anatomical cluster that consists of two or more adjacent bones or cartilages, which may be interconnected by various types of tissue.
A body tissue consisting of long cells that contract when stimulated and produce motion.
A fibrous, strong, connective tissue that connects muscle to bone.
A type of muscle used to create movement, by applying force to bones and joints. Usually attached to bones by tendons.
Involuntary muscle tissue consisting of uninucleate spindle-shaped fibers. Found within the walls of blood vessels, the alimentary tract, bladder, and reproductive tract.
Anatomical system that consists of the skin and its appendages.
Anatomical system that has as its parts the brain and spinal cord, nerves, ganglia, and parts of the receptor organs and that receives and interprets stimuli and transmits impulses to the effector organs.
One of the two major divisions of the nervous system. Its nerves connect the central nervous system with sensory organs, other organs, muscles, blood vessels and glands.
The organ of sight (visual apparatus), almost spherical in shape. At the end of development (NF stage 66) the eyes bulge out of their orbital capsules near the lateral edge of the dorsal side of the head.
The transparent front part of the eye that, together with the lens, refracts light.
A general term for the whole eye, or eye ball, of an organism.
A clear mucous membrane consisting of cells and underlying basement membrane that covers the sclera and lines the inside of the eyelids. It is made of epithelial tissue.
The opaque, fibrous, protective, outer layer of the eye containing collagen and elastic fiber.
A membrane in the eye, responsible for controlling the amount of light reaching the retina.
Circumferential tissue inside the eye composed of the ciliary muscle and ciliary processes.
Lateral neurogenic placode region positioned dorsally to the epibranchial placodes, and that includes the lateral line placodes, the otic placode and the trigeminal placode.
Cranial nerve that is continuous with the layer of nerve cells on the inner surface of the eye. It exits the neurocranium via the large optic foramen and is covered by a fibrous connective tissue sheath.
The combination of structures that form the ear and function to transmit vibrations and permit hearing.
A flattened, roughly circular cartilage derived from the extrastapes. This thin membrane or integument is stretched over the cartilaginous tympanic annulus in a drum-like manner, and forms the outer ear, receiving airborne vibrations and functioning in hearing.
The air-filled cavity within the skull that lies between the outer ear and the inner ear.
Labyrinthine anatomical cluster that comprises sensory endorgans specialized for vestibular, auditory, and acoustico-vestibular sensation.
Structure consisting of the vestibule, lagena, and semicircular canal, cavities that are hollowed out of the substance of the bone, and lined by periosteum. They contain a clear fluid, the perilymph, in which the membranous labyrinth is situated.
Inner ear structure into which the semicircular ducts find their outlet. Along with the saccule, it is part of the balancing apparatus (membranous labyrinth) located within the vestibule of the osseous labyrinth.
A major structure of the inner ear, ventral to the utriculus. Two small pouches extend from it: the papilla basilaris, and the papilla amphibiorum. The sacculus functions in the detection of sound.
A vestibular structure of the inner ear consisting of a ventral diverticulum off of the sacculus.
Any of the three fluid-filled ducts that loop from the utriculus in the inner ear, and help detect movement and maintain balance.
The small, oval, bony chamber of the labyrinth. The vestibule contains the utricle and saccule, organs which are part of the balancing apparatus of the ear.
Pigmented, smaller blastomere of the animal (upper) hemisphere of the cleaving embryo.
Anatomical region that is pigmented (dark brown) and tends to have the uppermost orientation, as it contains the blastocoel and cells that contain only small amounts of yolk. The Xenopus egg is divided into two roughly equal halves: the animal and vegetal hemispheres.
Any nerve outside the brain or spinal cord that connects with peripheral receptors or effectors.
A type of mesoderm that lies along the central axis, under the neural tube, and gives rise to the notochord.
The first appearance of the anatomical space that will become the blastocoel.
The dorsal surface of the blastocoel, the cavity of the blastula.
The opening of the archenteron to the exterior, marking the point of origin of the archenteron and the caudal end of the embryo.
Portion of tissue that contains cell bodies of neurons and is located outside the central nervous system.
Type of ganglion that is a condensation of sensory neurons on the dorsal root of each spinal nerve. There is one pair of spinal ganglia per myotome, with the spinal ganglia of the trunk region larger and more distinct from each other than those of the tail region.
Either of the pair of ganglionated longitudinal cords of the sympathetic nervous system of which one is situated on each side of the spinal column.
The narrow tube connecting the middle ear with the pharynx, through which air flows to equalize pressure on either side of the tympanic membrane.
Any of the three tiny bones of the inner ear (columella or stapes, the sacculus and the utriculus) suspended in the otic capsule.
The part of the nervous system that consists of the brain and spinal cord, to which sensory impulses are transmitted and from which motor impulses pass out, and that supervises and coordinates the activity of the entire nervous system.
A layer of skin between the epidermis (with which it makes up the skin) and subcutaneous tissues, composed of two layers, the papillary and reticular dermis.
An internal or external body part or prolongation that projects from, and is attached to, an organ or the main body of an organism.
Somitic compartment that is a precursor of dermis, the cells of which become arranged in a single layer that blankets the myotome, possibly continuously (unsegmented) across somites.
Invagination of thickened epithelium near the hindbrain that gives rise to a spherically shaped ear vesicle.
Vegetal portion of the marginal zone of the embryo that turns inside the embryo during involution.
The ectodermal precursor of the trigeminal ganglion. The profundal and the trigeminal ganglia are separate distally but fused at their proximal end as they condense around NF stage 24.
Equatorial zone of the zygote with which the plane of first cleavage aligns.
First trace of the future visual apparatus. The eye primordia forming antero-lateral evaginations of the closing neural tube are originally massive formations into which only a slit-shaped extension of the neural groove penetrates at NF stage 18. At NF stage 19 they clearly segregate from the anterior portion of the neural tube.
The evagination of neurectoderm, which has pinched off from the anterior neural keel, that precedes formation of the optic cup.
Randomly dispersed fibrils organized into criss-crossing fascicles or bundles in the coelomic envelope of oocytes.
Cell type that forms a layer within an ovarian follicle that surrounds the oocyte.
A monolayer of follicle cells surrounding the developing oocyte and forming adhesive contacts with the surrounding follicular epithelium.
The anterior part of the alimentary system, from the mouth and esophagus to the duodenum at the entrance of the bile duct. Structures of the foregut are: esophagus, stomach, duodenum, liver, gall bladder, and pancreas. The spleen is located in the foregut region, but is not a gut organ.
A zone found in the cytoplasm of the egg cells that contains determinants that will give rise to the germ cell lineage. As the zygote undergoes mitotic divisions the germ plasm is ultimately restricted to a few cells of the embryo. These germ cells then migrate to the gonads.
The nucleus of the oocyte, it is enclosed in a nuclear envelope and contains neucleoplasm, in which the chromosomes and extranucleoli are embedded. It breaks down as the oocyte matures, being no longer visible by the first meiotic metaphase.
Two migratory heart primordia that move ventrally during the course of neurulation, and whose fusion begins at the ventral midline at NF stage 16.
The first part of the small intestine. At the junction of the stomach and the duodenum the alimentary canal is inflected. The duodenum first goes anteriorly for a short distance, turns dorsally, and eventually caudally, thus it is a U-shaped structure with two horizontal sections (a ventral and a dorsal one).
The final section of the small intestine.
The terminal portion of the large intestine.
The pancreatic duct and common bile duct together, which enter the descending duodenum.
A thickened portion of ectoderm that serves as the precursor to the lens. It invaginates to form the lens vesicle, which gives rise to the crystallin-accumulating cells of the lens.
Vein that returns blood from the trunk and drains into the duct of Cuvier via the pronephric sinus.
Duct that drains the mesonephros and connects it to the ureter.
The last portion of the digestive system, it extracts water and salt from solid wastes before they are eliminated from the body.
The posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary tracts.
A prominent mass in the cytoplasm of previtellogenic oocytes. The cloud contains both mitochondria and electron-dense granulofibrillar material (GFM) and is the source of germinal granule material.
Space that separates the thicker inner sheet of splanchnic mesoderm from the thinner outer somatic mesoderm.
Second of the pharyngeal (endodermal) evaginations between the visceral arches from which the Eustachian tube is derived; pouches 2-4 open as gill slits.
The median dorsal longitudinal groove formed in the embryo by the neural plate after the appearance of the neural folds.
A region of embryonic ectodermal cells that lie directly above the notochord. During neurulation, they change shape and produce an infolding of the neural plate (the neural fold) that then seals to form the neural tube. At NF stage 11.5 is the first indication of neural plate within the sensorial layer of ectoderm. It extends to near the animal pole by NF stage 12.5 and the entire plate is faintly delimited by NF stage 13.
Posterior segment of the neural tube, which develops into the hindbrain and spinal cord.
Third of the pharyngeal (endodermal) evaginations between the visceral arches from which the Eustachian tube is derived; pouches 2-4 open as gill slits.
Spinal cord structure that is part of the ventricular system and is filled with cerebral-spinal fluid and runs the length of the spinal cord.
Animal portion of the marginal zone of the embryo that spreads in front of the animal cap but does not involute during gastrulation.
Fourth of the pharyngeal (endodermal) evaginations between the visceral arches from which the Eustachian tube is derived; pouches 2-4 open as gill slits.
Fifth of the pharyngeal (endodermal) evaginations between the visceral arches.
The developing female gamete, the differentiation of which is classified into six stages: I (pre-vitellogenic), II (early vitellogenic), III (mid-vitellogenic, formation of pigment), IV (polarization along animal-vegetal axis), V (late vitellogenic), and VI (post-vitellogenic, appearance of equatorial band).
An outpocketing of the foregut ventral to the infundibulum and the hypophysis. The walls surrounding this cavity are composed of endoderm.
Either of paired female reproductive organs involved in production of ova and female sex hormones.
Area of mesoderm at either side of the midline embryonic notochord that, on segmentation, forms the paired somites.
The space between the zona pellucida and the cell membrane of an oocyte or fertilized ovum.
Outer layer of the developing optic vesicle, which contains pigmented epithelium.
A small cell formed by the meiotic division of an oocyte.
A germ cell that is a primordial oocyte in a female and that develops into secondary oogonia by mitotic division.
Portion of tissue that consists of the mesenchymal precursor to the pronephric kidney and that begins to separate from the intermediate mesoderm at NF stage 21 and epithelializes by NF stage 30.
Sixth of the pharyngeal (endodermal) evaginations between the visceral arches.
Inner layer of the developing optic vesicle, which contains retinal nerve cells.
The hypophyseal layer that separates from the stomodeal layer of the stomodeal-hypophyseal primordium at NF stage 29 and 30.
A type of germ cell that results from the mitotic division of a primary oogonium.
Anterior part of the embryonic alimentary canal that is formed as an invagination of the ectoderm and is the future mouth.
Deep layer of the neural ectoderm, which undergoes early neuronal differentiation.
Layer of lateral plate mesoderm that forms the future body wall; it underlies the ectoderm.
An auxiliary olfactory sense organ involved in the detection of pheromones.
Organ comprising the specialized structures subserving the function of the sense of smell.
The point on the surface of the egg at which the sperm enters the egg.
A depression on the head of the embryo that becomes converted into a nasal passage.
splanchnic layer of lateral plate mesoderm
Layer of lateral plate mesoderm that forms the circulatory system and future gut wall; it overlies endoderm.
The internal nasal passages, aperture or cavity in the roof of the buccopharynx.
When the marginal zone mesoderm undergoes involution, where the marginal zone contacts the vegetal base.
Unpigmented, larger blastomere of the vegetal (lower) hemisphere of the cleaving embryo.
Anatomical region that is the lower, light-colored hemisphere of the egg, as its cells contain large amounts of dense yolk proteins. The Xenopus egg is divided into two roughly equal halves: the animal and vegetal hemispheres.
Cell mass in the vegetal region of the embryo that will contribute to endoderm.
Pharyngeal (endodermal) evaginations between the visceral arches from which the Eustachian tube is derived; pouches 2-4 open as gill slits.
A hole located in the center of the iris of the eye that allows light to enter the retina.
The three distinct placodal areas, which develop from the posterior placodal area, and lie ventral to the otic placode and dorsocaudal to the pharyngeal clefts, and contribute to the sensory ganglia and cranial nerves.
The structure that is the basic functional unit of the pronephros.
Portion of the pronephric tubule that is immediately posterior to the early proximal tubule and anterior to the early distal tubule.
Portion of the pronephric tubule that is immediately posterior to the late proximal tubule and anterior to the late distal segment.
Portion of the pronephric tubule that is immediately anterior to the late proximal tubule.
Pronephric segment immediately posterior to the early distal tubule and anterior to the pronephric duct.
The tissue made up of loosely connected mesenchymal cells in the mesonephros.
The structure that is the basic functional unit of the adult or mesonephric kidney, consisting of the vascular loop of the glomerulus, the capsule, the nephrocoel, the nephric duct, the nephrostome and the nephric tubule.
The cavity of the blastula, a closed space that is invaded by early mesenchyme and later obliterated by the enlarging archenteron. It forms during embryogenesis when a zygote (a fertilized ovum) divides into many cells through mitosis.
The portion of endoderm between dorsal and ventral blastopore lips, and extending towards to the blastocoel.
Anatomical direction relating to the vegetal pole or hemisphere.
Anatomical direction relating to the animal pole or hemisphere.
Spatial concept denoting the back or upper surface of the body.
Spatial concept denoting the underside or lower surface of the body.
Spatial concept denoting only the surface of the body.
Spatial concept denoting extension relatively far inward.
Spatial concept pertaining to the back of the body and to the side.
Spatial concept pertaining to the part of the body opposite the back and away from the midline.
Spatial concept pertaining to being situated at or extending to the side.
A localized ectodermal thickening that develops by apicobasal elongation of cuboidal cells in the inner layer of the ectoderm in the head of the embryos, and is involved in formation of sense organs.
Organizing center consisting of a small group of cells located at the ventral midline of the neural tube that influences the development of the nervous system, governing the specification of neuronal cell types and directing axonal trajectories.
Anterior segment of the neural tube, which develops into the forebrain and midbrain.
Region of the neural tube that will become the white matter of the nervous system.
The anterior U-shaped portion of the neural folds, the two longitudinal dorsal ridges, caused by a folding up of the ectoderm, that make their appearance on either side of the middle line of the early neural embryo.
Portion of the middle of the three primary germ layers of the embryo that resides on the periphery of the embryo, splits into two layers enclosing the intra-embryonic coelom, and gives rise to body wall structures.
Any of the transient, degenerating somites that form in the occipital region of the animal.
Any of the somites that are posterior to the head and anterior to the tail.
Somitic compartment that is a precursor of muscle.
The inner layer of the pericardium that is in contact with the surface of the heart. During cardiac development, it is the source of multipotent mesenchymal cells, which give rise to endothelial and smooth muscle cells in coronary vessels and also, possibly, to cardiomyocytes.
Multi-tissue structure that is the filtration unit of the pronephric kidney. A glomus is a glomerulus that spans more than one body segment. It is the vascularized filter of the pronephric kidney. Blood is filtered through the glomus and the filtrate deposited into the coelom early in development, or the nephrocoel later in development. The glomus contains podocytes with well developed foot processes that are anatomically indistinguishable from the podocytes of adult glomeruli. The two glomera are linked via a narrow bridge called the glomeral nexus.
Properly called a glomus as it extends over multiple body segments.
Neural crest cells that migrate along two major pathways: through the somites, to populate the skin where they give rise to pigment cells; cells migrating along the lateral pathway generate sensory and sympathetic ganglia and adrenal chromaffin cells, among others.
Type of ganglion that is separate distally from the trigeminal ganglia; they become fused at their proximal end as they condense.
A unique type of neurogenic placode, located ventral and caudal to the 2nd and 3rd pharyngeal pouches, which gives rise to small hypobranchial ganglia of yet unknown function.
Primordium of the spleen, which goes on to form the spleen proper, while the right splenic promordium degenerates.
Transient splenic primordia that degenerates by NF stage 40.
Internal lymphoid organ derived from left spleen primordia beginning at NF stage 48.
Transient developmental organ that gives rise to oviducts in females (and is documented to persist in some male frogs).
Structure that is equivalent to the convoluted proximal tubule of metanephric nephrons.
Structure that is the mesonephros nephron's equivalent to the straight proximal segment of a metanephric nephron.
The mesonephric equivalent of the ascending limb, or straight distal segment, of metanephric nephrons.
The site of bicarbonate resorption in the adult kidney. It is equivalent to the convoluted distal segment of metanephric nephrons.
The fused aspects of ventral mesoderm, which have migrated from either side of the prechordal plate, and fused ventrally, just behind the cement gland. They give rise to the endocardium at NF stage 27/28.
Region in the embryo that consists of precursor cells for the development of the embryonic heart.
The outlet of the embryonic heart; lies in the floor of the pharynx and conducts blood from the bulbus arteriosis to the aortic arches (1-6).
Of the paired ventral aortas in the tadpole, the one that branches into the left aortic arches.
Of the paired ventral aortas in the tadpole, the one that branches into the right aortic arches.
One of a series of six paired embryological vascular structures that give rise to several major arteries.
The anterior member of a series of six paired arterial connections between the dorsal and ventral aortae. Aortic arch that is part of mandibular arch.
The second in a series paired arterial connections between the dorsal and ventral aortae. Aortic arch that is part of hyoid arch.
The third in a series paired arterial connections between the dorsal and ventral aortae. Aortic arch 3 lies within the 3rd branchial arch and branches directly from the ventral aorta to the lateral dorsal aorta, and are retained as the branchial arteries providing circulation through the gills in the adult.
Artery that arises from the ventral aorta and delivers blood to the filter apparatus. It is visible as a bilateral pair of vessels on the ventral surface of the head, running between the heart and the tip of the jaw.
The aorta of a postembryonic, hatched or immature tadpole, prior to metamorphosis.
The fifth in a series paired arterial connections between the dorsal and ventral aortae. Aortic arch 5 artery is paired and has a common trunk with aortic arch 6 from the ventral aorta, and drains via a separate branch of the lateral dorsal aorta. Aortic arches 5 and 6 supply the trunk and tail with oxygenated blood.
The sixth in a series paired arterial connections between the dorsal and ventral aortae. Aortic arch 6 artery is paired and has a common trunk with aortic arch 5 from the ventral aorta, and drains via a separate branch of the lateral dorsal aorta. It forms part of the pulmonary arteries, and in the later embryo, the ductus arteriosis. Aortic arches 5 and 6 together supply the trunk and tail with oxygenated blood.
One of three branches of the internal carotid artery, the palatine artery supplies the mouth region.
The fourth in a series of paired arterial connections between the dorsal and ventral aortae, it lies within the 4th branchial arch. The paired aortic arch 4 arteries branch directly from the ventral aorta to the lateral dorsal aorta, and are retained as the branchial arteries providing circulation through the gills in the adult.
Simple squamous epithelium that lines blood and lymphatic vessels and the heart.
The thin layer of cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall.
Simple squamous epithelium that lines the veins.
The blood vessel that bifurcates from the aorta, and supplies the abdominal and pelvic regions.
Artery consisting of many branches which supply blood to various organs in the viscus. One of the major blood vessels, branching off the dorsal aorta and supplying the embryonic foregut organs: liver, stomach, intestine, spleen and pancreas.
One of paired arteries that extends dorsally from the systemic arch to supply the muscles of the jaw and back.
The posterior extension of the dorsal aorta to the tail region, which degenerates at metamorphosis.
Artery that branches from either side of the dorsal aorta and delivers blood to the musculature of the shoulder region.
One of the major arteries of the head, it is the cranial continuation of the aortic arches and the dorsal aorta. It curves ventrally before resuming a dorsal course as it enters the head proper, and it lies ventral to the internal jugular vein. The internal carotid artery gives off palatine, ophthalmic, and cerebral branches by NF stage 41.
The anterior continuation of the internal carotid artery, which gives off the nasociliary artery anterior to the eye.
A branch of the internal carotid artery that delivers blood to the eye. Together with the opthalmic vein, it forms a double ring encircling the eye and retina. It enters the eye obliquely by crossing over the ophthalmic vein and the internal jugular vein.
One of three branches of the internal carotid artery, it supplies the mouth region.
The artery that supplies the network of blood vessels (the mesentry) to the large intestine.
The rightmost of the two bilaterally symmetrical lymph hearts that can be seen adjacent to somites 3 and 4 by NF stage 40, and can be seen beating by NF stage 43. Lymph hearts are pulsatile organs, present in lower vertebrates, that function to propel lymph into the venous system.
The leftmost of the two lymph hearts, pulsatile organs that are present in lower vertebrates and function to propel lymph into the venous system. Two bilaterally symmetrical lymph hearts can be seen adjacent to the somites 3 and 4 by NF stage 40, and can be seen beating by NF stage 43.
Bilaterally paired longitudinal vein; the anterior cardinal returns blood from the head, and the posterior cardinal returns it from the trunk; these two vessels join together on each side as the common cardinal vein, also known as the duct of Cuvier that leads to the heart's sinus venosus.
Large subdermal lymph-containing space located dorsally near the last vertebrae.
A vessel that contains or conveys lymph.
Any of the veins in the embryo that return blood from the yolk sac to the heart or later to the portal vein.
The smallest of the blood vessels, parts of the microcirculation, of the liver.
Ventrolateral component of the external jugular vein.
One of the bilateral pairs of vessels clearly seen on the ventral surface of the head, running between the heart and the tip of the jaw, and draining the filter apparatus. This vein is more developed by NF stage 45, when it crosses the head dorsolaterally to drain into the Duct of Cuvier and pronephric sinus.
Vein that first appears as disconnected portions lateral to the Wolffian ducts at NF stage 44, gradually becoming continuous. They come into communication with the medial postcardinals at the kidney sinus.
Sinus that surrounds the mesonephric tubules and puts lateral and medial postcardinal veins into communication with each other.
The main dorsal head vein, it drains into the Duct of Cuvier, and collects blood from the dorsal jaw region, cerebral veins, the ophthalmic vein and the short pharyngeal vein. It forms loop around the olfactory bulb by NF stage 43.
Vein that returns blood from the dorsal head and drains into the duct of Cuvier via the pronephric sinus.
Vein that gives rise to the interrenal vein and pronephric sinus.
A system of vessels that initially swell from where the anterior and posterior cardinal veins meet before draining into the heart via the duct of Cuvier at NF stage 33 and 34, and then continue to narrow and fold into a characteristic S-shape by NF stage 37 and 38. It continues to loop on itself, at first a loose, then a dense knot of many vessels by NF stage 45.
Vein formed from fusion of the posterior cardinal veins and that extends caudally.
Vein that carries blood away from the liver.
Vein that carries de-oxygenated blood from the posterior part of the body to the sinus venosus.
One of the veins of the alimentary system. The subintestinal vein is on the right side of the gut and drains the gastric vein on its right side by NF stage 43. The gastric veins carry blood low in oxygen from the surface of the stomach, draining into the left omphalomesenteric vein.
Vein in the tail returning blood from the trunk and tail to the heart, leading directly into the posterior cardinal vein in the posterior trunk.
Vein that carries away fluid in the interstitial spaces.
Vein that starts in capillaries of the alimentary canal and ends in capillaries of the liver.
Vein in the tail returning blood from the tail to the heart.
Any of the veins that collect blood from the lungs and some small vesicles received from the esophagus.
Vein in the posterior region that drains the ventral abdominal wall.
Transient occipital somite that exists from NF stages 17 to 26 only.
Somitic compartment that is a precursor of the axial skeleton.
An elongated fibroblast type cell, the cytoplasm of which is stretched between the collagen fibres of the tendon.
Transient occipital somite that exists from NF stages 18 to 29 only.
Transient occipital somite that exists from NF stages 18 to 29/30 only.
Transient occipital somite that exists from NF stages 19 to late 30's.
Trunk somite that is initially the fifth somite, first forming around NF stage 19 and becoming more anteriorly positioned as the head somites degenerate. It is the most anterior somite by NF stage 45 and is adjacent to the otic vesicle.
Trunk somite that is initially the sixth somite and later becomes the secondmost anterior somite.
The 1st somite located posterior to the head.
The 2nd somite located posterior to the head.
The 3rd somite located posterior to the head.
The 4th somite located posterior to the head.
The 5th somite located posterior to the head.
Mesenchymal cells that break from the sclerotome. Such cells migrate from the somite to surround the notochord.
Mesenchymal covering surrounding the notochord, derived from sclerotomal mesenchyme.
The 6th somite located posterior to the head.
The 7th somite located posterior to the head.
The 8th somite located posterior to the head.
The 9th somite located posterior to the head.
The 10th somite located posterior to the head.
The 11th somite located posterior to the head.
The 12th somite located posterior to the head. This somite is resorbed at metamorphosis.
The 13th somite located posterior to the head. This somite is resorbed at metamorphosis.
The 14th somite located posterior to the head. This somite forms at NF stage 28, by which time head somite 1 has degenerated, and it is resorbed at metamorphosis.
The 15th somite located posterior to the head. This somite is resorbed at metamorphosis.
Cranial nerve that supplies the nasal organ. It leaves the olfactory lobe, passes through the fenestra olfactoria into the nasal capsule, and there divides into the ramus profundus and ramus dorsalis.
Sensory ganglion of the trigeminal nerve.
A prominent collection of touch-sensory neurons of the trigeminal or fifth cranial nerve, positioned beside the brain between the eye and the ear.
Any of the major paired nerves of the head or cephalic region. Twelve pairs of cranial nerves exit/enter the cranium through openings in the skull. The nerves contain efferent axons with motor and glandular functions, as well as afferent axons from cranial ganglia with sensory functions. They are numbered in a rostral to caudal sequence, with the exception of the lateral line nerves.
A depression in the roof of the developing mouth in front of the buccopharyngeal membrane. It gives rise to the anterior pituitary (adenohypophysis), a part of the endocrine system.
Each of a set of hard, bony enamel-coated structures in the jaws, used for biting.
Xenopus developmental stage that corresponds to the end of the animal's life.
The structure that enables tadpoles, which are suspension feeders, to trap food particles. The palatoquadrate, ceratohyal and the connecting muscles are responsible for the irrigation and ventilation of the filter apparatus.
Thickened placodal areas located anterior and posterior to the otic vesicle. There are 5 distinct lateral line placodes, each giving rise to a single lateral line nerve that will innervate lateral line hair cells and convey information on motion to the adjacent hindbrain.
Lateral line primordium that migrates ventrad along the posterior and ventral margin of the eye.
Lateral line situated along the dorsal margin of the eye.
A lateral line that is present on the trunk of the organism.
The initial thyroid precursor, which arises from the ventral aspect of the second pharyngeal pouch.
The movable, muscular organ on the floor of the mouth.
The most anterior, or first, pharygeal/branchial arch, composed of the mandibular process, forming the posterior border of the stomodeum, and the maxillary process anterior to the stomodeum, containing the first aortic arch.
A swelling from the 3rd visceral arch at NF stage 35 and 36, which co-occurs with a depression between the 3rd and 6th, forming the external gills by NF stage 39.
The second pharyngeal/branchial arch; it arises as a thickening of the pharygeal wall between the first and second branchial clefts; contains the second aortic arch; forms part of the hyoid bone, tongue and facial musculature.
The third in a series of paired bars in the wall of the pharynx, within which are formed the third aortic arch and the cartilage bar of the visceral skeleton, and forms and supports the gills.
Anatomical structure that includes small, calcitonin producing glands originating as epithelial growths from the sixth pharyngeal pouch.
The fourth in a series of paired bars in the wall of the pharynx, within which are formed the fourth aortic arch and the cartilage bar of the visceral skeleton; forms and supports the gills.
The functional units of the liver including the lobules.
Hollow tree organ, the organ parts of which consist of the bile ducts.
Sphincter muscle that is part of the pyloric region of the stomach.
A short lateral line that extends from the ear in a posterior-dorsal direction.
Lateral line situated along the posterior and ventral margin of the eye.
Lateral line complex that radiates on the ventral side of the head from a point between the eye and the base of the larval tentacle.
Thickened plate of ectoderm that contributes to the formation of the dorsal, middle, or ventral lateral line.
The dorsal-most part of the sensory system on the surface of the tadpole consisting of small sensory patches (neuromasts) distributed in discrete lines over the body surface. The lateral line system is stimulated by local water displacements and vibrations, and detects propulsion of the tadpole through the water, as well as facilitating schooling, prey capture, and predator and obstacle avoidance.
A lateral line that extends from the ear in a posterior direction between the upper and lower lateral lines.
Ventrally located lateral line that runs over the abdomen.
Cranial nerve of the caudal lateral line that enters the brain between cranial nerves VIII and IX; contains afferents and sensory efferents to the posterior lateral line ganglion and middle ganglion. Fibers from the posterior lateral line ganglion innervate the occipital dorsal lateral line and trunk lateral lines.
The pancreatic bud that gives rise to the accessory pancreatic duct.
Any of the large number of glands of the larval skin, particularly common in the fins and adjacent skin of the trunk; also formed in the former frontal gland area on the upper jaw.
A type of colored melanophore (mobile pigment cells of the dermis and epidermis) that contain fat-soluble carotenoids (obtained from the diet) and pteridines (synthesized from the cell) which are stored in pterinosomes. Their color depends on the pattern of carotenoids and pteridines. They are rarely found in pre-metamorphic larvae.
A pigment cell derived from the neural crest. The cell contains flat light-reflecting platelets, probably of guanine, in stacks called reflecting platets or iridisomes. The color-generating components produce a silver, gold, or iridescent color.
A break in the continuity of the optic cup where the two sides of the cup meet.
Neural tissue comprising the proximal part of either of the optic vesicles as they project towards the sides of the head; it remains narrow and constitutes the optic stalk (the peripheral part of each expands to form a hollow bulb).
The most anterior of 5 distinct and partially overlapping functional domains of the premigratory neural crest, which are intially part of the neural epithelium. CNC cells migrate through the extracelluar matrix in 4 highly conserved streams: the mandibular crest, hyoid crest, anterior branchial crest and the posterior branchial crest.
Anterior endoderm that develops into the lung buds, and in turn, the lungs. A pair of lateral diverticula just over the liver rudiment is formed by the floor of the foregut just anterior to the liver diverticulum.
Anatomical system that has as its parts the blood and lymph vessels.
Any of the vessels through which blood circulates in the body.
Structure that is part of the pineal system, is located in the skin on the dorsal surface of the head, and is exposed continuously to ambient illumination.
Muscle tissue forming the facial muscles, a group of striated muscles innervated by the facial nerves.
A pigment cell that contains melanin (a brownish-black pigment), is derived from the neural crest, and is patchily distributed in the epidermis of the tadpole.
General convention refers to "melanophores" in lower vertebrates and "melonocytes" in amniotes but there is little if any difference between cell types.
An outgrowth of the cloaca that links the pronephric kidney to the exterior of the organism.
The myoblast that forms the muscles of the anterior abdominal walls.
Portion of tissue that consists of mesodermally derived cells and intercellular matrix composed of protein fibers and carbohydrates, which supports, ensheathes and binds together other tissues.
The protrusion of mesenchymal tissue of the anterior cardinal vein which forms lymph sacs.
Inward fold on the surface of the embryonic ectoderm that develops into part of the anal passage. The most posterior section of the gut.
Notochordal membrane covering derived from notochordal epithelium. Its first indication is at NF stage 24, and it is a distinct membrane by NF stage 28.
Outer layer of cells of the differentiating notochord, which give rise to the elastica externa and interna.
One of two pancreatic primordia that give rise to a ventral pancreatic bud.
Second of two pancreatic primordia that give rise to a ventral pancreatic bud.
Either of the two ventral pancreas rudiments that join and fuse with the right end of the dorsal pancreatic rudiment.
Organ that serves as a transient kidney, providing osmoregulation during early developmental stages, and then degenerates during metamorphosis.
Material anatomical entity that has inherent 3D shape and is generated by coordinated expression of the organism's own genome.
Anatomical structure consisting of at least two non-overlapping organs, multi-tissue aggregates or portion of tissues or cells of different types that does not constitute an organism, organ, multi-tissue aggregate, or portion of tissue.
Anatomical group that has as its parts distinct anatomical structures interconnected by anatomical structures at a lower level of granularity.
Anatomical structure that is an individual member of Xenopus laevis.
Gonochoristic organism that can produce female gametes.
Gonochoristic organism that can produce male gametes.
An experimentally manipulated tissue or portion of the developing embryo, that can be culture alone (in vitro).
Ectoderm section that has been dissected from the embryo, and treated with activin, and maintained in vitro.
disaggregated/reaggregated ectoderm treated with activin
NF stage 8 ectoderm of Xenopus laevis embryos that have been cut and disaggregated. The cells have been treated with activin at a concentration to induce endodermal tissue. Afterwards the reaggregated cells have been cultured until control sibling embryos reach stage 12/13.
The main artery of the circulatory system which carries oxygenated blood from the heart to all the arteries of the body except those of the lungs.
A layer of cells produced during the process of gastrulation during the early development of the embryo, which is distinct from other such layers of cells, as an early step of cell differentiation. The types of germ layers are the endoderm, ectoderm, and mesoderm.
Anatomical structure that has as its parts a maximally connected cell compartment surrounded by a plasma membrane.
Anatomical structure that is a primary subdivision of the whole organism.
Cell type that contains a deposition of coloring matter, the first of which differentiate during late tailbud stage, and that by NF stage 56 has produced a fully differentiated larval pigmentation pattern.
Embryonic (precursor) cell of the myogenic lineage that develops from the mesoderm.
An undifferentiated cell produced by early cleavages of the fertilized egg (zygote).
A connective tissue cell that secretes an extracellular matrix rich in collagen and other macromolecules.
A germ cell that is a primordial spermatocyte in a male and that develops into secondary spermatogonia by mitotic division.
A type of germ cell that results from the mitotic division of a primary spermatogonium.
Type of neuron that is a primary mechanosensory cell, with peripheral neurites innervating the skin with free nerve endings. It first appears in trunk levels at NF stage 33/34, and at NF stage 35/36 has somas that are the largest in the spinal cord. It forms a nearly continuous double row of cells along the cord's medial dorsal surface and contributes ascending and descending axons to the dorsal tract. It appears well back in the tail by NF stage 39, begins to decline at NF stage 50 and is few in number, with pycnotic nuclei, at NF stage 55.
Cell that is the basic unit of nervous tissue, each consisting of a body, an axon, and dendrites, and the purpose of which is to receive, conduct, and transmit impulses in the nervous system.
Organism subdivision that is the part of the body consisting of the cranial and pharyngeal regions.
Organism subdivision that is the part of the body posterior to the head and anterior to the tail.
Organism subdivision that is the terminal, flexible posterior appendage of the larva. It is resorbed during metamorphosis beginning with degeneration of the notochord's distal tip at NF stage 61, followed by degeneration gradually extending to its more proximal regions and reaching its proximal end by NF stage 62. By NF stage 66 it exists only as a small dorsal swelling.
Organism subdivision that has as its parts the jointed appendages used for locomotion and manipulation.
Organism subdivision that is the collection of anatomical structures on the body surface.
Cavity in which food is initially ingested and generally contains teeth, tongue and glands.
One of the pair of limbs that are situated anteriorly, develop in sacs that separate them from the gill chamber, are well-defined buds by NF stage 48, are innervated by NF stage 51, and are ossified by NF stage 59.
One of the pair of limbs that are situated posteriorly, are evident as buds laterally by NF stage 47, and are innervated by NF stage 51.
One of several most distal parts of a limb.
Surface structure that provides one of the small external openings of the head that give passage to air for breathing.
An internal organ of the body; especially: one (as the heart, liver, or intestine) located in the great cavity of the trunk proper.
Any of the 5 digits that are the most distal parts of a hindlimb, each digit consisting of a single metatarsal, 2-4 phalanges, and a claw.
Any of the 4 digits that are the most distal part of a forelimb, each digit consisting of a single metatarsal and 2-3 phalanges. Xenopus forelimb digits are numbered 2-5, with no digit number 1.
Anatomical structure that has as its parts two or more portions of tissue of at least two different types and which through specific morphogenetic processes forms a single distinct structural unit demarcated by bona-fide boundaries from other distinct structural units of different types.
Multi-tissue structure that is not part of a compound organ.
Multi-tissue structure that is part of a compound organ.
Multicellular anatomical structure that consists of many cells of one or a few types, arranged in an extracellular matrix such that their long-range organization is at least partly a repetition of their short-range organization.
Anatomical structure that has as its parts two or more multi-tissue structures of at least two different types and which through specific morphogenetic processes forms a single distinct structural unit demarcated by bona fide boundaries from other distinct anatomical structures of different types.
An anatomical structure that exists only before the organism is fully formed.
An embryonic structure that is the rudiment or commencement of a part or organ.
Primary germ layer that can give rise to both mesoderm and endoderm.
Portion of tissue that consists of one or more layers of epithelial cells connected to each other by cell junctions and that is underlain by a basal lamina.
Portion of embryonic tissue consisting of loosely organized, undifferentiated mesodermal or neural crest derived cells, that have specific properties (they are migratory, have no polarity). Mesenchyme cells are incorporated into a wide variety of structures including connective tissue, blood, bone and cartilage as development continues.
Portion of tissue that consists of a fasciculated group of axons.
A mature female germ cell that is capable of initiating formation of a new individual by fusion with a male gamete.
Connective tissue in which fat is stored.
Anatomical structure associated with the gonads that vary in form among amphibians but are primarily composed of adipose tissue and are thought to be a source of nutrients for the gonads. A body of adipose tissue, in the form of finger-like projections, usually associated with the anterior end of the testis and ovaries. Fat bodies are suspended from the body wall by dorsal mesentry which is fused with the gonadal mesentry (the mesovarium or mesorchidium).
Region located near the pronephros and pronephric ducts that is a site of hematopoiesis in the embryo.
A simple ciliated tube through which the ovum travels from the ovaries to the cloaca and the external environment. It is lined with mucus-secreting glands that produce the jelly that surrounds the ovum.
A rectangle of dorsal mesendoderm and ectoderm from an early-gastrula-stage Xenopus laevis embryo. It is approximately 60 deg to 90 deg wide, extending from the bottle cells to the animal pole.
A relatively undifferentiated cell that retains the ability to divide and proliferate throughout life to provide progenitor cells that can differentiate into specialized cells.
A stem cell from which all cells of the lymphoid and myeloid lineages develop, including blood cells and cells of the immune system.
Spatial concept denoting the front surface of the body; often used to indicate the position of one structure relative to another.
Spatial concept denoting the back surface of the body.
Anatomical cluster consisting of a cartilaginous skull that begins to form during early tadpole stage.
Anatomical system that provides physical support to the organism.
Skeletal structure of the paired, anterior appendages.
Skeletal structure of the paired, posterior appendages.
Arched skeletal structure that supports the forelimbs, the rudiments of which can be distinguished in mesenchyme at NF stage 51, and is complete by NF stage 60.
Arched skeletal structure that supports the hindlimbs, begins to develop at NF stage 50, and is ossified by NF stage 66.
The anterior limb bud that develops into the fore limb; oval shaped in dorsal aspect by NF stage 50, and paddle shaped by NF stage 53; all four fingers and melanophores apparent by NF stage 54.
The posterior limb bud that develops into the hindlimb; a thickening of the ectoderm first noticeable at NF stage 47, innervated by NF stage 51. The hindlimb buds develop before the forelimb buds.
Skeletal structure that has as its parts the vertebral column, located in the dorsal part of the trunk, and is formed by a series of vertebrae. It provides suspension for the appendicular skeleton and protection for the spinal nerve cord.
Anatomical cluster that consists of all the vertebrae in the body.
Skeletal system that is part of the head, including the splanchnocranium, chondrocranium, and dermatocranium.
The first vertebra, which arises from the trunk somites 1 and 2.
The vertebra anterior to the sacral vetebra.
The 9th vertebra, which arises from the trunk somites 9 and 10. It joins the illia laterally at NF stage 60 and later coalesces with the urostyle in the midline of the pelvic girdle to form a single unit in the adult frog.
The bones that make up the tail region of the tadpole.
Skeletal element in the midline of the pelvic girdle that arises from somites 10-13. It is a rodlike caudal bony structure unique to anurans that lies within a compartment formed by the elongated, anteriorly oriented pelvic girdle. It is formed by the fusion of the neural arches of the 10th-13th vertebrae, and the posterior-most remnants of the hypochord. Timing of complete ossification varies between NF stages 62 and 66.
Anatomical structure consisting of a narrowly triangular chamber supported by a series of semicircular cartilages in which part of the sound-production system is located.
Skeleton encasing the brain and auditory apparatus.
Anatomical cluster consisting of the ventral portion of the first pharyngeal arch.
Paired cartilaginous component of the lower jaw that fuses together through a median inferior labial cartilage, resulting in a single curved bar of cartilage by metamorphic climax. During metamorphosis it is surrounded by the developing dentale and goniale.
Anatomical cluster consisting of the mandibular structures which connect the base of the lower jaw with the skull.
The dorsal portion of the first pharyngeal arch.
Any of the coiled tubules located in the testes in which spermatozoa are produced.
Cranial nerve that largely consists of somatic efferent fibers which innervate four eye muscles (m rectus superior, m obliquus inferior, and mm rectus inferior and anterior).
Somatic efferent nerve that runs to the superior oblique muscle of the eye.
Cranial nerve that branches into the ophthalmic (supplying the skin of the nose and upper jaw) and the mandibular (supplying the lower jaw). It originates from the lateral surface of the medulla and exits the cranium via the large prootic foramen.
A somatic motor nerve that runs to the eye muscles, arising from the ventral surface of the medulla and exiting the neurocranium via the optic foramen.
Cranial nerve that branches into the supraorbital (supplying the skin of the eye region and the lateral line organs here), the palatine (to the roof of the buccal cavity), and the hyomandibular (dividing into the jugular and mental branches).
Cranial nerve that runs to the ear. It has anterior and posterior rami which enter the auditory capsule via two foramina.
Cranial nerve that branches into the ramus communicans (to the skin), the pretrematic (to the walls of the pharynx and mouth, viscero-sensory fibers), and the larval post-trematic branch (lost in the adult).
Cranial nerve that branches into the lateral (to body sense organs) and the intestino-accessorial (to the skin, muscles of shoulder, hyoid, larynx, gut, lungs, and heart).
A dorsally projecting part of the brain concerned especially with the coordination of muscles and the maintenance of bodily equilibrium, situated between the brain stem and the back of the cerebrum.
Irregularly shaped cavity in the rhombencephalon, between the medulla oblongata, the pons, and the isthmus in front, and the cerebellum behind. It is continuous with the central canal of the cord below and with the cerebral aqueduct above, and through its lateral and median apertures it communicates with the subarachnoid space.
Posterior portion of the hindbrain that controls respiration, heartbeat, digestion, and swallowing as well as some locomotor responses.
A mixed nerve that carries motor, sensory, and autonomic signals between the spinal cord and the body.
Any of the projections on each side of the vertebra from the point where the neural arch lamina joins the pedicel for the articulation with the head of a single-headed rib or the upper head of a double-headed rib. Also called diapophyses. They provide surfaces for the attachment of muscles. In anurans, the term transverse process is used in reference to the processes associated with the presacral and postsacral vertebrae.
Anatomical structure consisting of a small, pointed keratinized appendage at the end of each of the three inner toes of the hindlimbs.
Compartment of head somite 1 that is a precursor of muscle.
Compartment of head somite 2 that is a precursor of muscle.
Compartment of head somite 3 that is a precursor of muscle.
Compartment of head somite 4 that is a precursor of muscle.
Compartment of trunk somite 1 that is a precursor of muscle.
Compartment of trunk somite 2 that is a precursor of muscle.
Compartment of trunk somite 3 that is a precursor of muscle.
Compartment of trunk somite 4 that is a precursor of muscle.
Compartment of head somite 4 that is a precursor of the axial skeleton.
Compartment of trunk somite 1 that is a precursor of the axial skeleton.
Compartment of trunk somite 2 that is a precursor of the axial skeleton.
Compartment of trunk somite 3 that is a precursor of the axial skeleton.
Compartment of trunk somite 4 that is a precursor of the axial skeleton.
Compartment of trunk somite 5 that is a precursor of muscle.
Compartment of trunk somite 6 that is a precursor of muscle.
Compartment of trunk somite 7 that is a precursor of muscle.
Compartment of trunk somite 8 that is a precursor of muscle.
Compartment of trunk somite 5 that is a precursor of the axial skeleton.
Compartment of trunk somite 6 that is a precursor of the axial skeleton.
Compartment of trunk somite 7 that is a precursor of the axial skeleton.
Compartment of trunk somite 8 that is a precursor of the axial skeleton.
Compartment of trunk somite 9 that is a precursor of muscle.
Compartment of trunk somite 9 that is a precursor of the axial skeleton.
Compartment of trunk somite 10 that is a precursor of the axial skeleton.
Compartment of trunk somite 10 that is a precursor of muscle.
Compartment of trunk somite 11 that is a precursor of the axial skeleton.
Compartment of trunk somite 11 that is a precursor of muscle.
Compartment of trunk somite 12 that is a precursor of the axial skeleton.
Compartment of trunk somite 12 that is a precursor of muscle.
Compartment of trunk somite 13 that is a precursor of the axial skeleton.
Compartment of trunk somite 13 that is a precursor of muscle.
Compartment of tail somite 14 that is a precursor of the axial skeleton.
Compartment of tail somite 14 that is a precursor of muscle.
Compartment of tail somite 15 that is a precursor of the axial skeleton.
Compartment of tail somite 15 that is a precursor of muscle.
Compartment of tail somite 16 that is a precursor of the axial skeleton.
Compartment of tail somite 16 that is a precursor of muscle.
Compartment of tail somite 17 that is a precursor of the axial skeleton.
Compartment of tail somite 17 that is a precursor of muscle.
Any of the somites that form posterior to the trunk and are resorbed at metamorphosis.
The principal auditory organ of the frog, which utilizes both mechanical and electrical (hair cell-based) frequency tuning mechanisms for hearing, located near the junction of the utricle and the saccule bones of the inner ear.
A sensory structure in the lagenar portion of an amphibian's membranous labyrinth between the oval and round windows.
Anatomical structure that produces gametes as well as certain sex hormones controlled by the pituitary gonadotropins. Reproductive organ that produces and releases eggs (ovary) or sperm (testis).
A mature male germ cell that develops from a spermatid.
A cell that is within the developmental lineage of gametes and is able to pass along its genetic material to offspring.
Primitive cell type that is involved in the reproduction of the organism beginning with the sexual differentiation of the gonads at NF stage 52. In males specifically, it migrates from the genital ridge cortical region into the medullary tissue, where it forms spermatogonia. In females it is embedded in the cortical region and multiplies as oogonia.
Male germ cell that is derived from spermatocytes and develops into spermatozoa.
Anatomical system that protects the body from foreign substances, cells, and tissues by producing the immune response and that includes especially the thymus, spleen, lymphoid tissue, lymphocytes including the B cells and T cells, and antibodies.
The immune system of a postembryonic, hatched or immature tadpole, prior to metamorphosis.
The complete system of biological structures and processes within the adult organism that protects against disease by identifying and killing pathogens and tumor cells.
A cell of the B cell, T cell, or natural killer cell lineage.
A lymphocyte that can spontaneously kill a variety of target cells without prior antigenic activation via germline encoded activation receptors and also regulate immune responses via cytokine release and direct contact with other cells.
A type of lymphocyte whose defining characteristic is the expression of a T cell receptor complex.
One of the two types of lymphocytes (the others being T cells). All lymphocytes begin their development in the bone marrow. B cells are involved in so-called humoral immunity.
An immature T cell located in the thymus.
Anatomical group that has its parts adjacent to one another.
Structure that is an early outgrowth of a presumptive limb.
Anatomical structure that consists of cell parts and cell substances and together does not constitute a cell or a tissue.
Acellular anatomical structure that consists of a thin sheet of fibrous proteins that underlie and support the cells of an epithelium. It separates the cells of an epithelium from any underlying tissue.
Compound organ that does not contain macroscopic anatomical spaces.
Compound organ that contains one or more macroscopic anatomical spaces.
Skeletal structure that has as its parts the pectoral and pelvic girdles, which articulate with the axial skeleton, together with their associated limbs, the forelimbs and hindlimbs.
Subdivision of skeleton that includes all dermal bones in the cranial skeleton.
Anatomical cluster that consists of the cartilages and bones that surround the brain.
An anatomical cluster that is part of the cranium and structurally supports the eye.
Anatomical cluster that is located in the anterior region of the neurocranium and provides structural support for the olfactory organs.
An anatomical cluster that is located in the posterior region of the neurocranium and forms the margin of the foramen margin and occipital condyles.
Anatomical cluster that forms the floor and side walls of the middle part of the cranium.
Anatomical cluster that is a posterolateral part of the neurocranium and structurally supports the vestibuloauditory system.
Regional skeletal system of the jaws, hyoid and branchial arches.
Skeletal subdivision comprising the skeletal elements of the hyoid arch.
Skeletal subdivision comprising the dorsal skeletal elements of the hyoid arch.
Skeletal subdivision comprising the ventral skeletal elements of the hyoid arch.
Skeletal and cartilaginous elements of the branchial arches; the last five of the set of seven pharyngeal arches; generally branchial arch no. 1 is the first branchial arch, or the third pharyngeal arch, but some authors do not follow this convention.
Skeletal and cartilaginous elements of the first branchial or pharyngeal arch.
Skeletal and cartilaginous elements of the second branchial or pharyngeal arch.
Skeletal and cartilaginous elements of the third branchial or pharyngeal arch.
Skeletal and cartilaginous elements of the fourth branchial or pharyngeal arch.
Any spatial descriptor that describes the orientation of the anatomical features of an embryo.
A region of the whole organism that contains a recognizable set of structures or anatomical entities.
Spatial concept pertaining to being toward the middle or inside.
Spatial concept denoting a part of the body that is closer to the center of the body than another part.
Spatial concept denoting a part of the body that is farther away from the center of the body than another part.
Non-material anatomical entity of three dimensions, that is generated by morphogenetic or other physiologic processes; is surrounded by one or more anatomical structures; contains one or more organism substances or anatomical structures.
The chamber of the heart that receives blood from the lungs.
The chamber of the heart that receives blood from the sinus venosus.
Cardiac chamber that consists of a wall that surrounds the cavity of a ventricle. The amphibian heart has a single ventricle and an outflow tract with an incomplete spiral septum.
Part of the nervous system responsible for processing sensory information.
The sensory system used for balance and hearing.
The sensory system used for olfaction (the sense of smell).
The sensory system used for the sense of taste.
Part of the circulatory system that consists of a series of vessels that collect blood (exclusive of erythrocytes) which seeps through capillary walls and return it to the veins. The lymphatic system of vasculature drains lymph fluid from the tissue spaces of most organs and returns it to the blood vasculature for recirculation. The lymphatic sytem functions in immune responses. Anurans generate a lot of lymphatic fluid, largely as a consequence of their very leaky vasculature and high interstitial compliance. Lymph is ultimately pumped into the venous system by paired, dorsally located lymph hearts. Hedrick et al (2007) showed that lung inflation and deflation assists lymph movement. Lymph is moved during lung deflation to the subvertebral sac from anterior and posterior lymph sacs. During lung inflation, increased lymph sac pressure moves lymph to axillary regions, where lymph hearts can return lymph to the vascular space.
Epithelium that lines the oral cavity, with many short microvilli as well as mucous cells, rodlet cells and taste buds.
Epithelium lining the pharynx, consisting largely of simple columnar epithelium.
Epithelium that is part of a developing tooth or dental organ.
Hollow epithelial tube on the dorsal side of the embryo that develops into the central nervous system.
Polymorphic cell type that forms cartilage.
Cell type that is a component of the glomus.
The cluster of bones in the wrist between the radius, ulna and metacarpus, they do not belong to individual fingers, but allow the wrist to move and rotate.
Each of the bones forming the part of the hand between the fingers and the wrist.
Either of the paired, long bones of endochondral origin formed by the fusion of the radius and ulna.
Either of the paired, elongate, cylindrical forelimb bones of endochondral origin that extend from the pectoral girdle (shoulders) to the elbows.
A bone of the wrist of the hindlimb, which remains cartilaginous until NF stage 66.
Each of the bones forming the part of the foot between the toes and the heel.
Bone of the lower hind leg, which undergoes ossification from NF stage 56 to stage 66.
Either of the paired, elongate, cylindrical bones of endochondral origin that form the thighs, extending from the pelvic girdles to the knees. Proximal bone of the hind leg, which begins to ossify at NF stage 55.
The layer within the retina where the photoreceptor cell receptor segments reside.
The monolayer of pigmented epithelium covering the neural retina.
The layer within the retina where the bipolar cells synapse with the photoreceptor cells.
The layer within the retina where the photoreceptor cell bodies reside.
Fiber layer adjacent the retinal ganglion cell layer that comprises its axons as they traverse to the optic nerve.
The layer of the retina composed of the cell bodies of bipolar cells, horizontal cells, and some of the cell bodies of amacrine cells.
Retinal layer composed of the basal lamina of Muller cells.
Innermost nuclear layer of the retina, consisting of retinal ganglion cells, containing neurons that project axons through the optic nerve to the brain.
A thin fenestrated layer of the pars nervosa retinae adjacent to the outer nuclear layer and through which extend the visual rods and cones.
The plexiform layer of the retina positioned between the inner nuclear layer and the ganglion cell layer and containing the dendrites of retinal ganglion cells and processes of bipolar and amacrine cells.
Structure that is the anterodorsal-most region of the midbrain and is responsible for auditory and visual reflexes.
Anatomical cavity bounded by the derivatives of the branchial arches.
Type of trunk muscle that lies ventral to the horizontal septum of the vertebrae and is innervated by the ventral ramus of the spinal nerves. The arise from migratory somitic cells along the lower margin of the trunk somites.
Trunk muscle that lies dorsal to the horizontal septum of the vertebrae.
Muscle that is located posterior to the head and anterior to the tail and consists of epaxial and hypaxial muscle.
A cell that takes up stuff and metabolizes it.
Any of the cell types of the digestive system that secrete amino acid peptides or polypeptides.
Exocrine functioning cells of the pancreas.
A cell that secretes alkaline substances.
A cell whose primary function is to prevent the transport of stuff across compartments.
A surface epithelial cell of stratified squamous epithelium of cornea, tongue, oral cavity, esophagus or cloaca.
A cell of ectomesenchymal origin concerned with the formation of the layer of cementum on the roots of teeth.
A cell that originates from a mesenchymal stem cell and forms chondrocytes (cartilage cells). Chondroblasts that become embedded in the matrix are called chondrocytes.
A cell that moves among different tissues of the body, via blood, lymph, or other medium.
A type of cell, found in the digestive tract, that secrete enzymes that break down polymeric macromolecules into their smaller building blocks, in order to facilitate their absorption by the body.
A cell found in the embryo before the formation of all the germ layers is complete.
A cell of the early embryo at the developmental stage in which the blastomeres, resulting from repeated mitotic divisions of the fertilized ovum (zygote), form a compact cell mass.
A cell of the embryo in the early stage following the blastula, characterized by morphogenetic cell movements, cell differentiation, and the formation of the three germ layers.
A cell of the outer of the three germ layers of the embryo.
A cell whose function is determined by the generation or the reception of an electric signal.
A cell of an endocrine gland, ductless glands that secrete substances which are released directly into the circulation and which influence metabolism and other body functions.
A cell of the inner of the three germ layers of the embryo.
A cell that is usually found in a two-dimensional sheet with a free surface.
A cell of an exocrine gland, i.e. a gland that discharges its secretion via a duct.
Individual secretory cells of the hatching gland that secrete an enzyme that dissolves or weakens the egg jelly and facilitates hatching.
A cell that is specialized to accumulate keratins, a family of fibrous structural proteins.
Type of cell that is capable of generating and maintaining the fibrous connective tissue of the ligament.
A modified epidermal cell located in the stratum basale. They are found mostly in areas where sensory perception is acute.
A cell of the middle germ layer of the embryo.
A type of epithelial cell, found in the epidermis and digestive system, whose function is to secrete mucin, which dissolves in water to form protective mucus.
A cell that is specialized to accumulate myelin.
A non-sensory cell type surrounding the neuromast support cells and neuromast hair cells, separating the neuromast from the epidermis, and secreting cupula in which the ciliary bundles of all the hair cells are embedded.
A non-sensory cell of the neuromast that extends between the sensory hair cells from the basement membrane to the apical surface; neuromast support cells are surrounded by neuromast mantle cells.
A non-ciliated columnar cell that extends from the epithelial free margin to the basement membrane of the olfactory epithelium.
A cell that is specialized to accumulate oxygen.
A secretory cell that secretes an agonist into intercellular spaces in which it diffuses to a target cell other than that which produced it.
A slender, contractile, mesenchymal-like cell found in close association with capillary walls. They are relatively undifferentiated and may become fibroblasts, macrophages, or smooth muscle cells.
A stem cell that can give rise to cell types of the body other than those of the germ-line.
Embryonic primordium consisting of an endodermal thickening that develops into the liver.
Either of the pair of structures lying on either side of the dorsal aorta in which fluid balance is regulated and waste is excreted out in the form of urine.
Type of presumptive precardiac cell that lie as paired primordia 30 to 45 degrees on either side of the dorsal midline of the embryo. As gastrulation proceeds, these migrate laterally, eventually fusing at the anterior ventral midline, where they differentiate into cardiac tissue. They give rise to the linear heart tube of the fused heart primordium and derive from the cardiac crescent.
Type of muscle that arises in the zygomatic arch and closes the jaw.
A tube shaped portion of tissue lined with epithelial cells that collects secretions and routes them to their destination.
Material anatomical entity in a gaseous, liquid, semisolid or solid state; produced by anatomical structures or derived from inhaled and ingested substances that have been modified by anatomical structures as they pass through the body.
Any of the sense organs that detect vibrations carried through water. They develop from a specialized series of dorsolateral ectodermal placodes named lateral line placodes.
Non-material anatomical entity of one dimension, which forms a boundary of an anatomical surface or is a modulation of an anatomical surface.
Epithelium that consists of epithelial cells not arranged in one ore more layers.
Anatomical structure that is contiguous with the embryo and comprises portions of tissue or cells that will not contribute to the embryo.
Epithelium that consists of more than one layer of epithelial cells.
Epithelium that consists of a single layer of epithelial cells.
Unilaminar epithelium that consists of a single layer of columnar cells.
Unilaminar epithelium that consists of a single layer of cuboidal cells.
Unilaminar epithelium that consists of a single layer of squamous cells.
Anatomical cluster of the central body axis including the cranium, vertebrae, notochord, ribs, and sternum.
Organ entity that is typically involved in mechanical support and may have different skeletal tissue compositions at different stages.
Skeletal element that is composed of cartilage tissue and may be permanent or transient.
Bone element that arises as a result of intramembranous ossification.
Skeletal element that forms superficially in the organism, usually in association with the ectoderm.
Skeletal element that forms as a replacement or substitution of another element or tissue.
A skeletal element that has the potential to participate in endochondral ossification, and may participate in intramembranous ossification.
Replacement bone that forms within cartilage.
Main component of the vertebral column. It consists of two essential parts, a dorsal neural arch and a ventral centrum.
Anatomical structure that is a natural outgrowth, projection, or appendage. A process can be part of a bone, cartilage, tissue, or fin.
Anatomical structure that is an aggregation of similar cells from which cartilages and bones form, and from which chondrogenesis and osteogenesis are initiated during repair and/or regeneration.
Cell condensation that is an aggregation of mesenchymal cells that are committed to differentiate into chondroblasts and chondrocytes.
Cranial skeleton derived from neural crest cells.
Anatomical cluster that encompasses the cranium and facial structures.
Skeletal subdivision that undergoes direct development and includes elements that either develop in association with the basement membrane of the ectoderm or are homologous with such elements; includes dermatocranium, components of the appendicular skeleton, teeth and tooth-like elements of the oropharynx, and integumentary elements.
Skeletal system that undergoes indirect development and includes elements that develop as a replacement or substitution of other elements or tissues.
Anatomical structure composed of a combination of protein fibers, ground substance and tissue fluid; typically has embedded cells.
Cartilage tissue intermediate between hyaline cartilage and dense connective tissue; contains of abundant collagen fibers; chondrocytes often arranged in columns.
Cartilage tissue primarily composed of type II collagen (thin fibrils) and a glassy appearance.
Connective tissue that is dominated by collagen fibers organized into a definitive pattern (e.g., parallel to one another), with comparatively fewer cells (mostly fibroblasts).
dense regular collagenous connective tissue
Dense regular connective tissue connecting two or more adjacent skeletal elements or supporting an organ.
A layer consisting mainly of proteins (especially collagen) and glycosaminoglycans (mostly as proteoglycans) that forms a sheet underlying or overlying cells such as endothelial and epithelial cells. The proteins are secreted by cells in the vicinity.
Proteinaceous extracellular matrix that is avascular and consists primarily of glycosaminoglycans.
Extracellular matrix that is mineralized.
Bone tissue that is an unmineralized bone matrix deposited by osteoblasts prior to the mineralization of bone tissue.
Avascular GAG-rich matrix that is mineralized.
non-mineralized avascular GAG-rich matrix
Avascular GAG-rich matrix that is not mineralized.
A specialized form of connective tissue in which the extracellular matrix is firm, providing the tissue with resilience, and/or mineralized and that functions in mechanical and structural support.
Bone tissue mineralized with hydroxyapatite.
Hyaline cartilage tissue that is mineralized.
Anatomical system comprising the sum of all muscles in the body.
Cartilage tissue that is not mineralized.
non-mineralized hyaline cartilage tissue
Hyaline cartilage tissue that is not mineralized.
Cell condensation that is a well-defined population of densely organized mesenchymal cells that aggregates adjacent to an epithelium.
Skeletal tissue that is part of the exoskeleton and derived from an odontogenic papilla.
Odontogenic papilla located along the jaws or pharyngeal skeleton.
Anatomical cluster that comprises the oral part of the pharynx.
A layer of dense irregular connective tissue that surrounds the cartilage of developing bone, consisting of two separate layers: an outer fibrous layer and inner chondrogenic layer. The fibrous layer contains fibroblasts, which produce collagenous fibers. The chondrogenic layer remains undifferentiated and can form chondroblasts or chondrocytes. Perichondrium is a type of connective tissue, and also functions in the growth and repair of cartilage. Once vascularized, the perichondrium becomes the periosteum.
Fibrous connective tissue that surrounds the notochord; includes a layer of elastin.
Collagen-rich odontogenic tissue characteristic of teeth and tooth-like skeletal elements (e.g., odontodes); mature dentine is mineralized and develops from predentine tissue; often (but not always) tubular and acellular.
Odontogenic tissue that is collagen-rich and characteristic of vertebrate teeth and tooth-like structures (e.g., odontodes) deposited by preodontoblasts and odontoblasts that are typically excluded from the matrix.
Anatomical cluster that consists of all the skeletal elements (eg, bone, cartilage, and teeth) of the body.
Connective tissue that is matrix-poor with large number of vacuolated cells.
Mesenchyme cells that proliferate in the progress zone of developing limb buds.
Portion of tissue comprising the posterior end of the tail fin.
Nerve that is a branch of cranial nerve VIII and innervates the cristae ampullaris.
A portion of tissue that is re-growing after damage or amputation.
A regenerating tissue composed of a proliferative mass of undifferentiated progenitor cells from which new differentiated structures arise.
The edge, and the area immediately adjacent to it, of the dorsal fin.
The fin at the posterior part of the body of the tadpole.
The unsupported flaps of epidermis-covered, loose connective tissue extending the length of the dorsal tail muscle, originating at or near the tail-body junction, and extending posteriorly to slightly beyond the tip of the notochord and tail musculature.
The edge, and the area immediately adjacent to it, of the ventral fin.
Portion of the cleavage-stage embryo below the equator and consisting of prospective endodermal cells.
During gastrulation, the ring of endodermal cells that overlie the larger sub-blastoral endoderm cells.
During gastrulation, the vegetal endodermal cells that lie just below the ring of smaller suprablastoral endoderm cells.
Neural crest that lose their connections to other neuroepithelial cells during the delamination process and begin to migrate. This involves either partial or complete epithelial-to-mesenchymal transition. Numerous molecules have been demonstrated to guide a neural crest cell's migration to its target tissue.
Multi-tissue structure that is part of the diencephalon ventral to the thalamus consisting of connecting fibers and is a center for control of the autonomous nervous system.
Decussation of cranial nerve II axons whereby some cross the midline and some remain ipsilateral.
The ventral region of the alar hypothalamus. It is a diencephalic nucleus that is part of the preoptic area and is ventrolateral to the caudal parvocellular preoptic nucleus.
Primary blood vessel sprouts that originate from the aorta and grow dorsally between the somites.
A tendon located in the intersomitic region.
Epithelium located in the intersomitic region.
Neuron located in the intersomitic region.
Any of the transient sequential subdivisions of the developing hindbrain, all posterior to the midbrain-hindbrain boundary.
The 2nd most anterior segment of the developing hindbrain, which along with r3 is dorsal to brancial arch 1.
The 3rd segment of the developing hindbrain, between rhombomeres r2 and r4, which along with r2 is dorsal to branchial arch 1.
The 4th segment of the developing hindbrain, between rhombomeres r3 and r5 and dorsal to branchial arch 2.
The 5th segment of the developing hindbrain, between rhombomeres r4 and r6, and dorsal to branchial arch 3.
The 6th segment of the developing hindbrain, directly bordering the midbrain-hindbrain boundary, and dorsal to branchial arch 4.
Specialized epithelial cells involved in the maintenance of osmotic homeostasis. They are characterized by abundant mitochondria and ion transporters.
Part of the neural ectoderm that will become the embryonic midbrain-hindbrain boundary.
One of the two edges of the neural groove.
The apical region of the animal hemisphere.
Anatomical region that surrounds the eye but is within the orbit.
Portion of tissue that is part of the anterior neural plate and will form the optic vesicle.
The portion of the embryonic ectoderm, including the preplacodal ectoderm, that does not give rise to nervous tissue.
The field of naive ectoderm at the anterior of the neurula stage embryo. It is positioned at the border between the future epidermis and the anterior neural plate/neural crest forming regions and is subdivided into 2 distinct domains: the anterior placodal region which is anterior to the neural plate, and the posterior placodal area which is lateral to the neural crest.
An embryonic structure positioned halfway between the prospective eye and ear, adjacent to the future midbrain-hindbrain boundary. The profundal and the trigeminal ganglia are separate distally but fused at their proximal end as they condense around NF stage 24.
Epithelium that borders the anterior and equitorial region of the lens. Lens growth occurs via the differentiation of additional fibre cells from lens epithelial cells.
The region of the lens of the eye where cells from the anterior epithelial capsule become transformed into the fibers that compose the lens substance.
Portion of tissue comprising fibers that form the bulk of the lens. They are long, thin, transparent cells.
A neuron that laterally connects other neurons in the inner nuclear layer of the retina.
A type of interneuron that has two neurites, usually an axon and a dendrite, extending from opposite poles of an ovoid cell body.
Interneuron of the retina. They integrate, modulate, and interpose a temporal domain in the visual message presented to the retinal ganglion cells, with which they synapse in the inner plexiform layer. They lack large axons.
Type of neuron that receives neural inputs via bipolar, horizontal and amacrine cells. The axons of these cells make up the optic nerve.
Diencephalic white matter (tract) that is composed of retinal ganglion cell axons after which they have passed through the optic chiasm.
The portion of the neural plate border that is anterior to the mid-hindbrain junction.
The portion of the neural plate border that is posterior to the mid-hindbrain junction.
The boundary between non-neural ectoderm and the neural plate of neurula stage embryos, giving rise to the neural crest and cranial placodes.
Any of bilaterally paired tubes that perform the resorptive and excretory functions of the pronephros, and which connect the pronephric glomeruli to the pronephric ducts.
A portion of forelimb tissue that is re-growing after damage or amputation.
A portion of hind limb tissue that is re-growing after damage or amputation.
A portion of tail tissue that is re-growing after damage or amputation.
A portion of eye tissue that is re-growing after damage or amputation.
A cell found in the retina of the eye that is specialized to detect and transduce light.
One of the two photoreceptor cell types in the retina. In cones the photopigment is in invaginations of the cell membrane of the outer segment. Cones are less sensitive to light than rods, but they provide vision with higher spatial and temporal acuity, and the combination of signals from cones with different pigments allows color vision.
One of the two photoreceptor cell types of the retina. In rods the photopigment is in stacks of membranous disks separate from the outer cell membrane. Rods are more sensitive to light than cones, but rod mediated vision has less spatial and temporal resolution than cone vision.
The apical region of the vegetal hemisphere.
A developing female gamete that is at the pre-vitellogenic stage.
A developing female gamete that is at the early vitellogenic stage.
A developing female gamete that is at the mid-vitellogenic stage.
A developing female gamete that is at the stage in which polarization along the animal-vegetal axis is established.
A developing female gamete that is at the late vitellogenic stage.
A female gamete that is at the fully grown stage.
A sheet of extracellular matrix that separates the outer myocardial cell layer from the inner endocardial tube in the early embryonic heart. As the heart is going through the looping stages, this extracellular matrix/cardiac jelly starts to thicken in two regions, the atrioventricular canal region and the ventricular outflow tract region. These two discrete swellings of cardiac jelly are known as cardiac cushions. The cardiac jelly plays a central role in the septation of the heart and comprises most of the thickness of the heart wall at early stages, but disappears as the heart differentiates.
A thickened layer of ectodermal cells at the distal tip of a developing limb bud. Along with the zone of polarizing activity, it is a crucial organizing region during limb development.
Anatomical cluster that consists of rapidly dividing cells.
The part of the heart connecting the atrium to the cardiac ventricle.
Endocardium that is part of the atrioventricular canal.
A portion of tissue forming a cusp guarding the opening of the atrioventricular valve.
Portion of tissue that prevents regurgitation of blood from the ventricles to the atria or from the pulmonary arteries or aorta to the ventricles.
Muscle that pulls the hyoid apparatus forward and depresses the lower jaw.
Muscle of the abdomen that continues anteriorly as the m. rectus cervicis.
Muscle that retracts the hyoid and, therefore, the tongue.
A mechanoreceptor cell located in the inner ear that is sensitive to auditory stimuli. The accessory sensory structures are arranged so that appropriate stimuli cause movement of the hair-like projections (stereocilia and kinocilia) which relay the information centrally in the nervous system.
Horizontal (lateral) patch of cristae/sensory epithelia cells of the inner ear.
Presumptive structure at the animal pole of the blastula that will develop into ectoderm.
Posterior patch of cristae/sensory epithelia cells of the inner ear.
Presumptive structure that will develop into paraxial mesoderm.
The interface between the dorsal neuroepithelium and the roof plate of the fourth ventricle. The source of a number of migratory neuron populations of the hindbrain.
Portion of tissue that is a patch of thickened, pseudostratified epithelium in the inner ear, consisting of regular arrays of sensory hair cells interspersed with supporting cells. The macula saccule senses linear acceleration and gravity.
Anterior patch of cristae/sensory epithelia cells of the inner ear.
A specialized epithelial cell involved in sensory perception. Restricted to special sense organs of the olfactory, gustatory, and vestibuloauditory systems; they contain sensory cells surrounded by supportive, non-receptive cells.
The portion of the heart through which blood flows into the pulmocutaneous and systemic arteries. It is derived from cardiac precusor cells of the secondary heart field, and septation is incomplete.
A portion of either the left ventricle or right ventricle of the heart through which blood passes in order to enter the great arteries. The right ventricular outflow tract (RVOT) is an infundibular extension of the ventricular cavity which connects to the pulmonary artery. The left ventricular outflow tract (LVOT), which connects to the aorta, is nearly indistinguishable from the rest of the ventricle.
The thin, spiral-shaped membranous structure within the ventricular outflow tract of the heart.
Ganglion that provides afferent innervation for hair cells associated with both the auditory and vestibular components of the inner ear. As the otic placode invaginates into a cup neuroblasts delaminate from the anterior ventral aspect of the otic epithelium to give rise to neurons of the vestibulocochlear (statoacoustic) ganglion of cranial nerve VIII.
Any network of intercommunicating blood vessels.
Region that is overlapping, anterior, and dorsal to the main body of the ventral blood island.
A small, oval, bony chamber of the labyrinth. The vestibule contains the utricle and saccule, organs which are part of the balancing apparatus of the ear.
A pluripotent cell in the ventral blood island that can give rise to mesenchymal cells including erythrocytes and endothelial cells.
One of two veins that run upward at first in front, and subsequently on either side of the intestinal canal. They unite on the ventral aspect of the canal, and beyond this are connected to one another by two anastomotic branches, one on the dorsal, and the other on the ventral aspect of the duodenal portion of the intestine, which is thus encircled by two venous rings; into the middle or dorsal anastomosis the superior mesenteric vein opens. The portions of the veins above the upper ring become interrupted by the developing liver and broken up by it into a plexus of small capillary-like vessels termed sinusoids.
A cell of the monocyte, granulocyte, mast cell, megakaryocyte, or erythroid lineage.
Cell that comprises the outermost layer or lining of anatomical structures and can be squamous or cuboidal.
An immature or mature cell in the lineage leading to and including erythrocytes.
Posterior vascular precursor cells of the tail region.
Blood vessels of the retina. May be visible in periocular stainings.
Vessels that are associated with the posterior region of the lens.
The hyaloid artery is a branch of the ophthalmic artery, which is itself a branch of the internal carotid artery. It is contained within the optic stalk of the eye and extends from the optic disc through the vitreous humor to the lens. Its purpose is to supply nutrient to the developing lens.
Network of intersecting blood vessels associated with the posterior region of the lens.
Vein that crosses the head dorsally at NF stage 37/38 and drains into the vena capitis medialis.
Vein that drains the dorsal longitudinal vessel and the caudal portions of the venous capillary network of the medulla oblongata. The cerebral veins cross the head dorsally at NF stage 37-38. It drains into the vena capitis lateralis.
The cerebral veins are divisible into external and internal groups according to the outer surfaces or the inner parts of the hemispheres they drain into. The veins are the anterior cerebral veins, posterior cerebral veins, and middle cerebral vein which cross dorsally between the bilateral vena capitis lateralis.
Type of vein that crosses the head dorsally at NF stage 37/38 and drains into the vena capitis lateralis.
Type of artery that carries blood from the heart to the lungs. They are the only arteries that carry deoxygenated blood. Develops from aortic arch 6.
A mesenchymal stem cell capable of developing into blood vessel endothelium.
Type of vein that sprouts from the posterior cardinal vein, growing dorsally between the somites, and then joining, and draining the dorsal longitudinal anastomosing vessel.
The small branching sprouts of the dorsal aorta that grow across the medial surface of the somite, turn right angles to grow over that surface and then fuse with other sprouts and form the vertebral arteries adjacent to the neural tube; the intersomitic arteries supply the body wall and persist in the adult as the posterior intercostal, subcostal and the lumbar arteries.
In the trunk region, one of the veins into which the subintestinal vein drains, and which breaks up to merge with the vitelline network at NF stage 40.
The artery that crosses the brain dorsally, and meets the metencephalic vein.
The vein that crosses the brain dorsally, parallel with the mid-cerebral vein, and meets the metencephalic artery.
The dorsal branch/remnant of the vena capitis medialis, that drains blood from the eye. Together with the opthalmic artery, form a double ring encircling the eye and retina.
One of the major dorsal head veins that drains into the anterior cardinal vein, the other being the vena capitis lateralis.
One of the major dorsal head veins that drains into the anterior cardinal vein, the other being the vena capitis medialis.
Vein that is formed from and drains into the left omphalomesentric vein, and by NF stage 40, it is on the left side of the gut. It moves to the most ventral aspect of the gut during stage 41, and is on the right side of the gut by stage 43.
The major artery of the midbrain, which crosses the midbrain medially to meet its partner the mesencephalic vein.
The major vein of the midbrain, which crosses the midbrain medially to meet its partner the mesencephalic artery.
The main artery of the olfactory region which arises from the cerebral artery at NF stage 41.
A plexus of capillaries that is located anteromedial to the eye. It is a capillary layer in the choroid. It is in contact with the basal surface of the retinal pigmented epithelium and supplies the photoreceptors with oxygen and nutrients. The fused basement membrane of this capillary layer and the pigmented epithelium is called Bruch's membrane.
Vessel into which intersomitic vessels enter in a regular pattern at each intersomitic junction. Posterior to the gut, the DLAV drains into the fused posterior cardinal vein by a minor right branch and a major left branch. By NF stage 36 the DLAV extends fully to the tip of the tail.
dorsal longitudinal anastomosing vessel - left branch
The major (left) branch of the dorsal longitudinal anastomosing vessel (dlav); it remains as the sole branch after the right branch breaks up at NF stage 44.
dorsal longitudinal anastomosing vessel - right branch
The minor (right) branch of the dorsal longitudinal anastomosing vessel (dlav); the right branch disappears during NF stage 44.
Part of the telencephalon, comprising paired anterior outgrowths of either of the cerebral hemispheres in which the olfactory nerve exits. The olfactory bulbs begin to fuse at NF stage 50, and fusion is complete around NF stage 58. The cerebral vein loops around the olfactory bulb by NF stage 43.
Type of myocyte that is responsible for heart contraction.
The outer membrane/wall of the developing heart, surrounding the myocardium. Peritoneum that surrounds the heart.
Muscle that is paired and runs anterio-posteriorly along the heart and is covered with epicardium.
The field of cardiac progenitor cells that form the heart tube in the embryonic heart.
The population of cells located in the splanchnic mesoderm that contribute to the formation of the spiral septum of the outflow tract of the embryonic heart; it is located anterior to the primary heart field.
Branchial crest that is the 3rd neural crest stream and lays between hyoid crest and posterior branchial crest.
Branchial crest that is the most posterior of the five neural crest streams.
The discrete swellings of cardiac jelly in the outflow tract and ventricular walls of the developing embryonic heart.
Neural crest that develops from the dorsal neural tube. It overlaps the vagal neural crest and migrates to contribute to the pharyngeal arches 3, 4 and 6 (producing structures in the head) and to the heart where it contributes to connective tissue (septa) that separates the vessels of the heart. Cardiac neural crest develops into melanocytes, cartilage, connective tissue and neurons of some pharyngeal arches.
One of the 5 distinct and partially overlapping functional domains of the premigratory neural crest. Together with the sacral neural crest cells, they develop into the ganglia of the enteric nervous system, also known as the parasympathetic ganglia. These cells, between the head and trunk, contribute post-cranially to the heart and gut, the chromatophores (pigment cells) of the epidermis, and the majority of the neurons and glial cells of the enteric nervous system. Both vagal and sacral neural crest cells contribute to the enteric nervous system in the hindgut.
One of the 5 distinct and partially overlapping functional domains of the premigratory neural crest. Together with the vagal neural crest cells, they develop into the ganglia of the enteric nervous system, also known as the parasympathetic ganglia. Sacral crest cells are associated with extrinsic nerve fibers of the hindgut and colon.
Skeletal element that is often isolated, small, and variable in composition.
Ossicle that is part of the appendicular skeleton.
Mineralized bone tissue that always includes non-terminally differentiated osteoblasts and osteocytes.
Odontoid tissue that is deposited by cementoblasts onto dentine tissue and functions to attach teeth, odontodes and other odontogenic derivatives to bone tissue and the integument.
Cartilage tissue that is flexible and contains abundant elastic fibers.
Skeletal tissue that consists of an avascular, noncollagenous, hypermineralized matrix that is deposited by ameloblasts that are excluded from the matrix. It develops from organic pre-enamel tissue that is replaced by a largely inorganic matrix.
Skeletal tissue that is hypermineralized and aprismatic and deposited by a combination of ameloblasts and odontoblasts that are excluded from the matrix. It develops from pre-enameloid tissue.
Chondroid tissue that is not mineralized.
Skeletal tissue that is avascular tubular mineralized matrix, primarily made of dentine that is deposited by odontoblasts that are excluded from the matrix; develops from pre-dentine tissue.
Odontogenic tissue that is avascular non-mineralized matrix that is deposited by preameloblast and ameloblasts that are excluded from the matrix.
Odontoid tissue that is avascular non-mineralized matrix that is deposited by odontoblasts and ameloblasts that are excluded from the matrix.
Replacement element; an ossicle; often an endochondral replacement element that has cartilage and bone states that develops in dense regular connective tissue (e.g., tendons and ligaments).
A sac-like cavity ventral to the liver, lying in the sub-mesodermal space and closed by a thin sheet of ectodermal cells, from which the future gall bladder develops.
One of the 2 subregions of the pre-placodal ectoderm, which lies abutting and anterior to the neural plate.
One of the 2 subregions of the pre-placodal ectoderm, which lies abutting and lateral to the neural crest.
The small pre-placodal ectoderm area that develops at the midline of the anterior neural ridge, abutting the anterior neural plate, and invaginates to form Rathke's pouch, which in turn forms the anterior lobe of the pituitary gland and gives rise to the endocrine secretory cells of the pituitary.
The region that delineates the rostral boundary of the neural plate in the neural stage embryo, and is devoid of neural crest cells. It gives rise to the pre-placodal region, some elements of the forebrain, and the anterior lobe of the pituitary gland.
The region of the diencephalon above Rathke's pouch, and forms the posterior lobe of the pituitary.
The most anterior of the epibranchial placodes, associated with the 1st pharyngeal cleft and contributing to the distal ganglia of cranial nerve VII (facial nerve).
The central of the three epibranchial placodes, associated with the 2nd pharyngeal cleft and contributing to the distal ganglia of cranial nerve IX (glossopharyngeal nerve).
The most posterior of the epibranchial placodes, in 3 distinct zones, associated with the 3rd to 6th pharyngeal clefts, and contributing to the facial, lateral line and glossopharyngeal ganglion.
Small motor nerve that emerges from the lateral wall of the medulla with the roots of the vagus nerve, and innervates a single pectoral suspensory muscle, the m. cucullaris.
Duellman and Trueb (pg. 395) note that although the primordia of this nerve are in the 1st and 2nd spinal nerves, this nerve contains fibers representing the hypoglossal nerve in amniotes and is thus considered one of the cranial nerves.
Nerve that leads to the muscles of the tongue (mm geniohyoideus, genioglossus, hyoglossus, and rectus cervicis) and has both sensory and motor functions.
The narrow bridge that links the two glomera of the pronephric kidney.
An efferent neuron that passes from the central nervous system or a ganglion toward or to a muscle and conducts an impulse that causes movement.
The dorsal component of the mandibular arch, the ventral one being Meckel's cartilage. Together with the ceratohyal and connecting musculature, it is responsible for the ventilation and irrigation of the filter apparatus.
Cartilaginous element that, together with the palatoquadrate and connecting musculature, is responsible for the ventilation and irrigation of the of the filter apparatus.
Lateral line placode that gives rise to the anteroventral lateral line nerve.
Lateral line placode that gives rise to the anterior lateral line nerve.
Lateral line placode that gives rise to the middle lateral line nerve.
Lateral line placode that gives rise to the posterior lateral line nerve.
Type of epithelium that facilitates the transcellular transport of solutes. This transport can either be absorption, transport from lumen (apical membrane surface) to blood; or secretion, transport from blood (basolateral membrane surface) to lumen.
Type of cell of the epidermis lacking cilia, which separate and space the ciliated epidermal cells.
Region of the mesencephalon that arises from a small area of the neural plate, spanning the midline immediately adjacent, and being slightly posterior to the dorsal tegmentum area.
Region of the mesencephalon that arises from a small area of the neural plate immediately adjacent and slightly anterior to the ventral tegmentum area.
Laterally located vein that drains the ventral abdominal wall.
The thin epidermis extension of the inner fin visible in the mid trunk region of the inner fin at NF stage 27, and extending posteriorly and then ventrally, ending just before the proctodeum. The fin is more homogeneous in NF stage 46 tadpoles, and the inner fin and fin crest are no longer discrete.
Anterior part of the hypothalamus, given rise by the midanterior neural ridge along with the chiasmatic ridge during forebrain morphogenesis.
A single long structure at each corner of the mouth that has muscle fibers attached to an internal cartilaginous support and that is mobile.
The exit for respiratory water in the tadpole.
A cranial continuation of the bulbis cordis that contains two lateral branches and divides into the carotid arch, systemic arch, and pulmocutaneous arch.
Multi-tissue structure through which the blood exits the heart. It is a chamber that functions as a capacitor, maintaining continuous blood flow into the gill arches.
Posterior part of the hypothalamus, given rise by the midanterior neural plate during forebrain morphogenesis.
A distinct elevation of a transient proliferating cell mass of the subventricular zone; this mass contributes most of its cells to the striatum; however, neocortex, thalamus, septum and olfactory bulb neurons are also partly derived from the LGE.
A cartilaginous element that is the primordium or commencement of a femur.
The most posterior of the hind digits, consisting of a single metatarsal, 2 phalanges, and a claw.
Type of vein that drains the gill region and which passes backwards lateral to the gill chambers and opens into the pronephric sinus.
A vein of the hind limb, first visible in the developing hind limb bud at c. NF stage 50 when it enters the ventral commissural vessel.
The accompanying artery of the ischiadic nerve.
Either of the primary veins in the hindlimbs that collect blood from the hindlimb region.
Part of the lateral pretrosal artery that supplies blood to the roof of the mouth.
A type of artery that supplies the deep structures of the facial region. It branches from the external carotid artery.
The 7th segment of the developing hindbrain.
A major artery of the neck that branches from the subclavian arteries and merge to form the single midline basilar artery.
Artery that supplies the anterior wall of the abdomen.
Artery that supplies blood via branches to the gonads, oviducts, and kidneys.
Vein that collects blood from muscles of the head and drains into the external jugular vein.
Vein that comes from the skin of the trunk.
Vein that comes from the subcutaneous tissue of the hindlimb stylopod.
One of three major veins that enter the sinus venosus.
Vein that collects blood from the forelimb via the branchial veins and from the muscles and skin of the trunk via the anterior epigastric and lateral veins.
Either of the veins that collect blood from the trunk and skin and drain into the subclavian vein.
A vein formed by the combination of veins in the pelvic region that collects blood from the liver, stomach, intestines, and gall bladder.
Structure that comprises the base region of the telencephalon.
A distinct elevation of a transient proliferating cell mass of the subventricular zone; this mass contributes most of its cells to the neocortex; however, hippocampal neurons, thalamus, septum and olfactory bulb neurons are also partly derived from the MGE.
Any of the outpocketings of pharyngeal endoderm that interdigitate with the neural crest derived pharyngeal arches. The pouches later fuse with the surface ectoderm to form the gill slits.
Region encompassing the oral end of the alimentary canal.
Lymphatic vessel located in the posterior ventral region of the trunk, ventral to the posterior cardinal vein.
Limb segment that is the proximal part of the limb (i.e. the humerus of the forelimb, and the femur of the hindlimb, and surrounding tissues).
Limb segment that is the middle part of the limb (i.e. the radio-ulna of the forelimb, and the tarsus and tibia-fibula of the hindlimb, and surrounding tissues).
Limb segment that is the terminal part of the limb (i.e. the metacarpels and phalanges of the forelimb, and the metatarsals and phalanges of the hindlimb, and surrounding tissues).
The 8th and most posterior segment of the developing hindbrain.
A multipolar neuron that connects afferent neurons and efferent neurons in neural pathways. They are found within the central nervous system and enteric nervous system.
A lateral line that extends from the ear in a posterior-ventral direction.
Lateral line placode that gives rise to the anterodorsal lateral line nerve.
Any of a field of cells in the posterior section of the foregut that will give rise to the liver bud and dorsal and ventral pancreatic buds.
Multi-tissue structure that is the ventral part of the midbrain.
Any of the neuronal precursor cells that are isolated and scattered throughout the anterior ventro-lateral region of the embryo, generally in a punctate pattern, immediately below the ectoderm.
Anatomical system that consists of all the joints of the body.
Ossicle that is part of the axial skeleton.
Skeletal element that is composed of bone tissue.
Median fin skeleton supporting the caudal fin.
Paired bone that is part of the shoulder assembly, joining the scapula to the front end of the sternum.
Skeletal subdivision of the head that includes the skull (cranium plus mandible), pharyngeal and/or hyoid apparatus.
Median fin skeleton located on the dorsal surface of the organism.
Fin that is an unpaired fin located in the sagittal plane of the organism.
Postcranial axial skeleton that is unpaired and located on the sagittal plane of the organism.
Appendage that is one of the anterior or posterior paired appendages (i.e. the forelimbs and hindlimbs).
Appendage that is one of the anterior paired appendages (i.e. the forelimbs).
Appendage that is one of the posterior paired appendages (i.e. the hindlimbs).
Bone that forms the posterior part of the pectoral (shoulder) girdle.
Skeletal element that surrounds the notochord.
Skeletal element that forms around the notochord and is part of the vertebral column.
Anatomical cluster consisting of the skeletal elements that are part of the skeleton.
Anatomical structure that is part of a cell and that has a granularity level equal to that of a protein complex or higher.
A solution obtained by rupturing cells (especially unfertilized oocytes) and removing all particulate matter.
Region of the oocyte vegetal cortex that contains a subdomain of ER organized on top of the mitochondrial cloud and where localization of Vg1 mRNA takes place.
Contractile ring formed at the division plane of the oocyte during first cleavage.
Stylopod (the limb segment closest to the body) that is part of a forelimb.
Stylopod (the limb segment closet to the body) that is part of a hindlimb.
Limb segment that is the middle part of the forelimb (i.e. the radio-ulna and surrounding tissues).
Limb segment that is the middle part of the hindlimb (i.e. the tarsus and tibia-fibula and surrounding tissues).
Terminal portion of a hindlimb that bears weight and allows locomotion.
Part of the diencephalon that is located between the prethalamus, hypothalamus, and the telencephalon.
Structure that comprises the roof region of the telencephalon.
Multi-tissue structure that is the dorsal part of the diencephalon and the major sensory input to which is visual.
Multi-tissue structure forming the anterior part of the diencephalon and lying between the thalamus, hypothalamus, and eminentia thalami.
A narrow stripe of cells that lies between the prospective dorsal and ventral thalami. This boundary contains signals that pattern the prethalamic and thalamic territories of the future mid-diencephalon.
A midline paired symmetrical structure within the brain; the main product of the embryonic diencephalon.
Mesoderm that will give rise, along with cranial neural crest cells, to connective tissue, bone and musculature in the head.
Any of the non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons in the brain, and for neurons in other parts of the nervous system such as in the autonomic nervous system. Neural crest derived.
Any of the cells that are of neural crest origin, now in place in their postmigratory target tissues, such as the sciatic nerve, dorsal root ganglia, gut or skin. They can be visualised or detected by specific molecular markers.
Bone of the ear that is connected to the tympanic membrane via the extrastapes. This structure is the amphibian ear ossicle, also known as the columella. It extends between extrastapes cartilage and the oval window. The extrastapes forms a cartilaginous tympanic disk.
A portion of limb tissue that is re-growing after damage or amputation.
A portion of fin tissue that is re-growing after damage or amputation.
Anatomical region at which two or more bones make contact and that includes some of the surrounding tissues of various types.
A joint region within a digit, one of several most distal parts of a limb.
A cell of the perichondrium, the fibrous membrane of connective tissue covering the surface of cartilage.
Anatomical region between digits, the most distal parts of a limb.
A portion of tissue that has been removed from the body.
A portion of fin tissue that has been removed from the body.
A portion of limb tissue that has been removed from the body.
Multipotent stromal cell that can differentiate into a variety of cell types, including: osteoblasts (bone cells), chondrocytes (cartilage cells), and adipocytes (fat cells).
Lymphatic vessel located in the posterior dorsal region of the trunk.
Any of the muscle that is part of the head.
Any of the paired mandibular arch muscles.
Any of the bilateral hyoid arch muscles innervated by cranial nerve VII.
Any of the muscles that support the filigreed structure of the gill basket necessary for filter feeding, through the stabilisation, extension and compression of the gill basket.
Straplike muscle that arises from elements of the pectoral girdle and passes to the hyoid bone and laryngeal cartilages.
A muscle that is part of the eye region and controls the movement of the eye.
Muscle that is part a complex that arises from the skull roof and acts to elevate or close the lower jaw. It separates medially from levator mandibulae longus supeficialis, with which it shares a common origin.
Muscle that is part a complex that arises from the skull roof and acts to elevate or close the lower jaw. After separating from levator mandibulae longus superficialis, it parallels it and inserts in the connective tissue. Only at later stages, its rostral third is slightly curved laterally and inserts in the region of the anlage of the tentacular cartilage.
m. levator mandibulae longus superficialis
Muscle that is part a complex that arises from the skull roof and acts to elevate or close the lower jaw. The first mandibular arch muscle to appear, it originates ventral to the center of the eye, and extends rostroventrally to end lateral to the buccal cavity.
Muscle that is part a complex that arises from the skull roof and acts to elevate or close the lower jaw. It originates from the ventral bend of the anlage of processus muscularis palatoquadrati. It runs ventrally near the levator mandibulae longus supeficialis and inserts anterior of it at Meckel's cartilage.
Muscle that is part a complex that arises from the skull roof and acts to elevate or close the lower jaw. The last jaw levator to develop, it originates rostral to the palatoquadrate.
Ventral muscle of the larval head that is a broad transverse sheet lying between the Meckel's cartilages and joining its opposite mid-ventrally in an median raphe.
Hyoid arch muscle that connects Meckel's cartilage with the palatoquadrate and supports the opening of the mouth by depressing Meckel's cartilage.
Large, tapering muscle that originates on the muscular process and inserts on the ceratohyal.
A thin curved muscle located between the ceratohyal cartilages.
Deep, visceral muscle associated with tongue movement.
Muscle situated between the planum hypobranchiale and the basihyobranchial, presumably to stabilize the connection between these elements.
Muscle that springs from the second branchial arch, meeting its opposite in a mid-ventral raphe.
The 1st branchial levator muscle, which contributes to raising the branchial apparatus.
The 2nd branchial levator muscle, which contributes to raising the branchial apparatus.
The 3rd branchial levator muscle, which contributes to raising the branchial apparatus.
The 4th branchial levator muscle, which contributes to raising the branchial apparatus.
Muscle that arises on part of the chondrocranium and passes to the ventro-lateral region of the cerato-branchialia. It originates on the ventrolateral process of the palatoquadrate.
Muscle that arises on part of the chondrocranium and passes to the ventro-lateral region of the cerato-branchialia. It is located on the crista parotica and commissura branchio-cranialis.
Muscle that arises on part of the chondrocranium and passes to the ventro-lateral region of the cerato-branchialia. It is a small muscle situated at the posterior end of the branchial skeleton.
Muscle that consists of dorsal and ventral parts that arise from medial raphe and insert on the arytenoid cartilages.
Muscle that arises from the edge of levator arcus branchialis IV and inserts on the arytenoid cartilage and the cricoid ring.
Type of muscle that attaches to the larynx.
Muscle in the orbit that inserts on the anterior side of the eye and the function of which is adduction of the eyeball.
Muscle in the orbit that inserts on the posterior side of the eye and the function of which is adduction of the eyeball.
Muscle in the orbit that depresses, adducts, and helps extort (rotate laterally) the eye.
Muscle in the orbit, the primary function is of which is elevation.
Thin, narrow muscle placed near the anterior margin of the floor of the orbit.
Muscle in the upper, medial side of the orbit whose primary action is downward, lateral rotation of the eye.
Cartilaginous element that is median and is the anterior-most cartilage of the ventral hyoid arch.
The cartilaginous element below the epibranchial in branchial arch 1.
The cartilaginous element below the epibranchial in branchial arch 2.
The cartilaginous element below the epibranchial in branchial arch 3.
The cartilaginous element below the epibranchial in branchial arch 4.
Cartilaginous element comprising the rostral connection of the palatoquadrate cartilage to the neurocranium.
Cartilaginous element that supports the anterior end of the nasal organ.
The space where the trabeculae of the tadpole chondrocranium have not yet fused.
One of the cartilaginous surfaces of the tadpole jaw.
The wide gap that separates the palatoquadrate from the neurocranium.
Cartilaginous element comprising cartilages that articulate with Meckel's cartilage in the lower jaw and are fused medially.
Cartilaginous element comprising the anterior process of ceratohyal cartilage derived from the hyoid neural crest stream.
Cartilaginous element comprising the articular process that forms the jaw joint with the posterior end of Meckel's cartilage.
Cartilaginous element comprising the ascending process that helps anchor the larval palatoquadrate to the neurocranium.
Rod-shaped paired cartilages located on either side of the notochord and involved in the formation of the base of the chondrochranium.
Cartilaginous element comprising the lateral process of ceratohyal cartilage derived from the hyoid neural crest stream.
One of the cartilaginous elements that meet and articulate in the median plane posterior to the basibranchial.
Cartilaginous element that is posterior to the cornua trabeculae.
Cartilaginous element comprising the muscular process, a flattened triangular process that is the site of attachment for the orbitohyoideus and suspensoriohyoideus muscles.
Cartilaginous element comprising the posterior process of ceratohyal cartilage derived from the hyoid neural crest stream.
Cartilaginous element comprising the dorsal component of the mandibular arch.
processus retroarticularis of Meckel's cartilage
Cartilaginous element that forms at the posteroventral tip of Meckel's cartilage.
Cartilaginous element that comprises a crescent-shaped plate that supports the tentacular cartilage in the upper jaw.
Cartilaginous element comprising a pair of chondrification centers in the base of the embryonic cartilaginous neurocranium.
Peripherally located part of the vegetal cell mass of prospective endoderm.
Cartilaginous element that comprises the network-like cartilaginous skeleton of the gill region.
Region of the ciliary marginal zone, at the edge (most distal region) where retinal stem cells are located.
Region of the ciliary marginal zone where retinal progenitor cells are located.
ciliary marginal zone progenitor cell region
Ganglion in the midbrain that gives rise to the fibers of the oculomotor nerve.
Multi-tissue structure that is the dorsal part of the thalamus and emerges ventral to the caudal portion of the ventral habenular nucleus.
The nucleus of the trochlear nerve (cranial nerve IV).
A type of mucus surface cell in the tadpole.
Type of epithelium in the embryonic epidermis that is mucus-secreting and ciliated.
The presumptive cells of the hatching gland, present by the end of gastrulation.
Centrally located part of the vegetal cell mass of prospective endoderm.
Regenerating tissue consisting of mesenchyme cells at the tip of the regenerating limb.
A layer of epidermal cells that initially covers the surface of an amputation site. Fibroblasts from the surrounding connective tissue migrate across the amputation surface to meet at the center of the wound. These fibroblasts multiply to form a blastema, which are the progenitors for the new limb.
Regenerating tissue that forms the inner or basal layer of wound epidermis.
Regenerating tissue that forms the outer layer of wound epidermis.
Tissue consisting of a cartilaginous rod or rods of a regenerating zeugopod segment of a limb.
A layer of signaling cells at the apex of a regenerating blastema, which has a vital role in regeneration.
Following amputation in late prometamorphosis or in young froglets, tissue comprising fibroblast-like cells in a limb stump that aggregate beneath the wound epithelia.
Regenerative tissue that develops and covers cut bone in the tadpole.
The predominant cell type in the epidermis, the primary function of which is the formation of a barrier against environmental damage.
A type of special epithelial cell that secretes mucus into the subsurface extracellular compartments of the epidermis.
Presumptive structure that will develop into axial mesoderm.
Mesenchyme that occupies the proximal region of a limb bud.
Mesenchyme that occupies the anterior proximal region of a limb bud.
Mesenchyme that occupies the posterior proximal region of a limb bud.
Mesenchyme that occupies the interdigital region of a limb bud.
Portion of tissue that migrates and deposits immature neuromasts and interneuromasts.
The 2nd most posterior of the hind digits, consisting of a single metatarsal, 2 phalanges, and a claw.
The 3rd most posterior, or middle, of the hind digits, consisting of a single metatarsal, 3 phalanges, and a claw.
The 2nd most anterior of the hind digits, consisting of a single metatarsal, 3 phalanges, and a claw.
The most anterior and longest of the hind digits, consisting of a single metatarsal, 3 phalanges, and a claw.
Portion of tissue consisting of unkeratinized cells at the most distal end of a developing digit and which will become a claw.
Claw located at the end of the 1st hindlimb digit.
Claw located at the end of the 2nd hindlimb digit.
Claw located at the end of the 3rd hindlimb digit.
Claw located at the end of the 4th hindlimb digit.
Claw located at the end of the 5th hindlimb digit.
Ganglion that develops from a cranial ectodermal placode and contains sensory neurons that innervate the posterior lateral line system.
Anatomical region comprising the central part of the retina.
m. levator mandibulae longus internus primordium
The presumptive cells of the levator mandibulae longus internus muscle.
m. levator mandibulae longus profundus primordium
The presumptive cells of the levator mandibulae longus profundus muscle.
m. levator mandibulae longus superior primordium
The presumptive cells of the levator mandibulae longus superior muscle.
m. levator mandibulae articularis primordium
The presumptive cells of the levator mandibulae articularis muscle.
m. levator mandibulae externus primordium
The presumptive cells of the levator mandibulae externus muscle.
The presumptive cells of the intermandibularis muscle.
The presumptive cells of the quadrato-hyoangularis muscle.
The presumptive cells of the orbitohyoideus muscle.
The presumptive cells of the interhyoideus muscle.
The presumptive cells of the subarcualis rectus I muscle.
The presumptive cells of the transversus anterior muscle.
The presumptive cells of the transversus ventralis II muscle.
mm. levator arcuum branchialium I primordium
The presumptive cells of the levator arcuum branchialium I muscles.
mm. levator arcuum branchialium II primordium
The presumptive cells of the levator arcuum branchialium II muscles.
mm. levator arcuum branchialium III primordium
The presumptive cells of the levator arcuum branchialium III muscles.
mm. levator arcuum branchialium IV primordium
The presumptive cells of the levator arcuum branchialium IV muscles.
mm. constrictores branchiales II primordium
The presumptive cells of the constrictores branchiales II muscles.
mm. constrictores branchiales III primordium
The presumptive cells of the constrictores branchiales III muscles.
mm. constrictores branchiales IV primordium
The presumptive cells of the constrictores branchiales IV muscles.
The presumptive cells of the geniohyoideus muscle.
The presumptive cells of the rectus cervicis muscle.
The presumptive cells of the constrictor laryngis muscle.
The presumptive cells of the dilatator laryngis muscle.
The presumptive cells of laryngeal muscle.
The presumptive cells of the rectus anterior muscle.
The presumptive cells of the rectus posterior muscle.
The presumptive cells of the rectus inferior muscle.
The presumptive cells of the rectus superior muscle.
The presumptive cells of the obliquus inferior muscle.
The presumptive cells of the obliquus superior muscle.
The presumptive cells of any of the cranial muscles.
A sharp boundary, running parallel to the outside of the embryo, between involuted mesoderm and external ectoderm. It runs from the blastopore to the upper limit of the involuted mesoderm.
Ganglion that develops from a cranial ectodermal placode and contains sensory neurons that innervate a lateral line.
Anatomical region comprising the peripheral part of the retina.
Cartilaginous element that is below the trabecula and parachordal.
Portion of tissue comprising the vascular layer of the eye, containing connective tissue and lying between the retina and the sclera. It provides oxygen and nourishment to the outer layers of the retina. Along with the ciliary body and iris, it forms the uveal tract.
Site above the branchial arch complex where vagal neural crest cells temporarily arrest their migration before entering the pharyngeal arches and heart.
Single cell layer of involuted endoderm lying beneath the prechordal plate.
Embryonic endoderm that evaginates to form the paired pharyngeal pouches.
The most anterior segment of the developing hindbrain.
Canal that connects the membranous labyrinth of the ear with the endolymphatic sac.
Multi-tissue structure that comprises a secretory epithelial layer and a connective tissue layer.
Cell component comprising the outer layers of the zygote.
Multi-tissue structure that is the outermost layer of an organ.
A small tissue element in the form of a beam, strut, or rod that generally has a mechanical function and is usually composed of dense cartilaginous tissue.
A type of trabecula that consists of a rounded or irregular column that projects from the inner surface of the ventricle of the heart.
Cardiac septum that separates the right atrium from the left atrium.
A large quadrangular cavity that precedes the atrium on the venous side of the heart.
Embryonic structure that is induced by the organizer to become lateral mesoderm.
Anatomical region that surrounds the otic vesicle.
A mature contractile cell, which has as part of its cytoplasm myofibrils organized in various patterns. Found in muscle tissue, myocytes are long, tubular cells that arise developmentally from myoblasts to form muscle. There are specialized forms: cardiac, skeletal, and smooth muscle myocytes, with various properties.
The most posterior digit of a forelimb, consisting of a single metatarsal, 3 phalanges, and a claw.
The second most posterior digit of a forelimb, consisting of a single metatarsal, 3 phalanges, and a claw.
The second most anterior digit of a forelimb, consisting of a single metatarsal, 3 phalanges, and a claw.
The most anterior digit of a forelimb, consisting of a single metatarsal, 2 phalanges, and a claw.
Neural crest-derived cell type that gives rise to the epicardium.
Cell that is present in the stem cell region of the retinal ciliary marginal zone.
Cell that is present in the progenitor cell region of the retinal ciliary marginal zone.
An endocrine cell that has the specialized function to produce and secrete hormones in response to neuronal signals.
Anatomical structure that has as its direct parts two or more types of tissue and is continuous with one or more anatomical structures likewise constituted by two or more portions of tissues distinct from those of their complement.
Organ part consisting of the rounded end of a long bone (at its joint with adjacent bone), which in Xenopus are the tibia-fibula and femur of the hindlimb, and the radio-ulna and humerus of the forelimb.
Organ part consisting of the main section or midsection of a long bone, which in Xenopus are the tibia-fibula and femur of the hindlimb, and the radio-ulna and humerus of the forelimb.
A cone-shaped hypomorphic structure consisting of a single continuous cartilage, typical of a regenerated forelimb or hindlimb when amputated after a specific developmental stage.
The apical region of a developing forelimb bud which will form the autopod segment of the forelimb.
The apical region of a developing hindlimb bud which will form the autopod segment of the hindlimb.
The physical groove that forms between cells at the first cell division. One-celled oocytes (NF stage 1) undergo cytoplasmic reorganization driven by sperm entry in the animal pole, where the cleavage furrow initiates, and it moves circumferentially along a line of longitude as well as progressing inwards through the cytoplasm, ultimately dividing the fertilized oocyte into two cells of equal size, defining NF stage 2.
The presumptive cells of the pelvic girdle.
A prominent, slender, rod-like projection of the iliac bone located close to the acetabiulum and directed posteriorly.
The presumptive cells of the iliac process.
Either of the paired bones that are the dorsal-most and largest bones of the pelvic girdle. They begin to connect to the sacral vertebra (9th vertebra) at NF stage 59.
Any of the posterior and smaller bones of the pelvic girdle. The ischia appear at NF stage 53, grow toward each other at NF stage 55, fusing and beginning to ossify by NF stage 58/59.
The ventral and anterior of the three principal bones composing the pelvic girdle. The pubes fuse with the ilia at NF stage 53, and touch each other at NF stage 62. Full contact of the medial surfaces occurs at NF stage 63 when ossification also begins. Ossification continues through metamorphosis.
Vertebra posterior to the sacral vertebra. The 4 postsacral vertebrae fuse and ossify (NF stage 66) to form the urostyle.
Any of the bony lateral projections from the presacral veterebrae of the anterior trunk region, enabling the lungs to expand and thus facilitate breathing by expanding the chest cavity. They serve to protect the lungs, heart, and other internal organs of the thorax.
A cell that is in the process of programmed cell death. The process is characterized by morphological changes (e.g. blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation) ending in cell death.
A cell that is in the process of replication, and is idenitifable by chromosomal replication.
A membrane that lines the outer surface of all bones, except at the joints of long bones. It consists of dense irregular connective tissue, and is divided into an outer fibrous layer and inner osteogenic layer. The fibrous layer contains fibroblasts, while the osteogenic layer contains progenitor cells that develop into osteoblasts, which are essential to the healing process.
The outer layer of the periosteum, containing acellular connective tissue and fibroblasts.
The inner layer of the periosteum, containing osteoblasts.
The tissue or tissues between the digits of the forelimb and the hindlimb.
Skeletogenic cell that secretes osteoid, is capable of producing mineralized matrix, is located adjacent to or within osteoid tissue, and arises from the transformation of a preosteoblast cell.
Mesenchyme that is part of a mandibular component.
Layer of lateral plate mesoderm that forms the body wall lining and dermis.
Type of precursor cell from which melanophores develop.
The endoderm cells that are fated to become the hindgut.
The endoderm cells that are fated to become the midgut.
The endoderm cells that are fated to become the foregut.
The upper surface of the vegetal yolk mass which forms the floor for the blastocoel (cavity) of the early gastrula embryo.
A ciliated cell that is not part of the epidermis.
The proximal segment of the pronephric tubule, closest to the glomus and functioning in solute resorption and waste excretion.
The distal segment of the pronephric tubule, functioning in water resorption, with urine passing through it into the pronephric duct.
A distal stem cell region of the proximal tubule. There are 3 branches, with anteriodorsal, anterioventral, and posterior positions. These are sometimes referred to as proximal tubule segment 1 or PT1.
A fluid-filled cavity formed within the mesoderm of the embryo.
Cell that is part of the neural crest region of the neuroepithelium, prior to migration.
Neuron that is part of the enteric nervous system.
The undifferentiated, loose connective tissue of the pharyngeal region, that is derived mostly from mesoderm, and also contains ectodermally derived neural crest cells.
Water-filled cavity in the adult frog that is apposed to an olfactory epithelium for detection of aqueous odorants.
Air-filled cavity in the adult frog apposed to an olfactory epithelium for detection of airborne odorants.
Sensory neuron responsible for detection of odorants.
The 16th somite located posterior to the head. This somite is resorbed at metamorphosis.
Portion of tissue in an eye consisting of the iris, ciliary body, and choroid.
The forebrain region that coordinates sensory signaling arising from the vomeronasal organ; it is located on the dorsal-posterior portion of the main olfactory bulb, and the axons that leave the accessory olfactory bulb project to targets in the amygdala and hypothalamus.
An almond-shaped set of neurons in the medial temporal lobe of the brain that is involved in the linkage of environmental information with social behavior and action selection.
A nucleus comprising the anterior aspect of the amygdala, adjacent to the basal forebrain, and involved in receiving olfactory information.
A forebrain white matter structure consisting of a large fiber bundle, connecting the two cerebral hemispheres across the middle line.
Nucleus situated in the pallidum that provides auditory input to the torus semicircularis.
Region of spinal cord white matter lying on either side between the ventral median fissure and the ventral roots of the spinal nerves.
Nucleus situated in the thalamus that is associated with the limbic system and is implicated in learning and episodic memory.
Nucleus located anterodorsally in the midbrain tegmentum.
Nucleus located anteroventrally in the midbrain tegmentum.
A group of structures that lie in the ventralmost parts of the forebrain and are formed by the derivatives of the subpallium.
Composite structure derived principally from the subpallium and containing numerous ganglia of the ventral telencephalon.
A brain structure in the forebrain wrapped around the stria terminalis. Its largest extent can be found around the crossing of the anterior commissure.
A nucleus comprising the central aspect of the amygdala, identified as a target for ascending auditory information from the central thalamic nucleus and as a major afferent to the vocal pattern generator of the hindbrain.
Nucleus that is located centrally in the thalamus.
A nucleus that is situated in the brainstem.
Cell mass in the caudal and dorsal aspect of the dorsal thalamus adjoining the pineal gland.
The predominant portion of the globus pallidus in the striatopallidal system, which is defined by connectivity and neurochemical staining. It is distinguished from the ventral pallidum by a boundary that is partially defined by the anterior commissure.
Subdivision of thepallium that is located dorsally.
A set of septal nuclei comprising the dorsal aspect of the forebrain septum.
external plexiform layer of the olfactory bulb
Cytoarchitectural part of the olfactory bulb, lying superior to the mitral cell layer and inferior to the glomerular layer. The EPL is mostly neuropil composed almost entirely of mitral and tulfted cell dendrites and granule cell dendrites and their synaptic inputs.
Superficial layer of the olfactory bulb, composed of spherical glomeruli, where input from olfactory receptor neurons is first organized and processed.
Type of neuron characterized by having very small cell bodies. These cells are found within the granular layers of the cerebellum and the olfactory bulb.
The innermost layer of the cerebellar cortex, containing densely packed small neurons, mostly granule cells.
granule cell layer of the olfactory bulb
A layer of the olfactory bulb interior to the mitral cell layer, consisting of inhibitory interneurons.
Region of the thalamus adjoining the pineal gland.
Nucleus that is a prominant part of the visual system, receiving input from the ipsilateral tectum and sending output to both tecta.
A nucleus comprising the lateral aspect of the amygdala, implicated in fear conditioning.
A fiber system that is formed by pallial and subpallial components that join in the caudal telencephalon. It proceeds caudally, piercing the optic tract, to the ventral part of the hypothalamus.
Region of spinal cord white matter that is both ventral to the dorsal root and dorsal to the ventral root.
Diencephalic nucleus that is the lateral part of the ventral hypothalamic zone.
Subdivision of the pallium that is located laterally.
A set of septal nuclei comprising the lateral aspect of the forebrain septum.
A nucleus situated in the brainstem, spanning the midbrain tegmentum and the pontine tegmentum.
Nucleus within the brainstem that is the principal site for brain synthesis of norepinephrine.
A nucleus situated in the preoptic area that contains large neurosecretory neurons.
A nucleus comprising the medial aspect of the amygdala, involved in receiving olfactory information.
Subdivision of the pallium that is located in the medial position.
A set of septal nuclei comprising the medial aspect of the forebrain septum.
Large glutaminergic nerve cell whose dendrites synapse with axons of the olfactory receptor neurons in the glomerular layer of the olfactory bulb, and whose axons pass centrally in the olfactory tract to the olfactory cortex.
Layer composed of pyramidal neurons whose cell bodies are located between the granule cell layer and the plexiform layer.
A region of the brain consisting of a collection of neurons located in the forebrain ventral to the caudate and putamen.
A brain structure that is part of the septal nuclear complex and is connected with the hippocampus, hypothalamus, and amygdala.
Major component of the basal ganglia that is part of the telencephalon and has close functional ties with the subthalamus.
Diencephalic tract that is located in the vicinity of the dorsal diencephalon and mesencephalon and connects the pretectal nuclei.
Region of spinal cord white matter that is dorsal and medial to the dorsal root.
Nucleus located posterodorsally in the midbrain tegmentum.
Nucleus located posteroventrally in the midbrain tegmentum.
Area of the forebrain anterior to the posterior tuberculum and the hypothalamus and ventral to the ventral thalamus.
A cluster of nuclei found in the brain stem, the main function of which is to release serotonin to the rest of the brain.
Gray matter structure located on the midline of the forebrain consisting of the septum pellucidum and the septal nuclei.
A compact fiber bundle that extends longitudinally through the posterolateral region of the medulla and is surrounded by the nucleus of the solitary tract, and descends to the upper cervical segments of the spinal cord.
A region of the forebrain consisting of the caudate nucleus, putamen and fundus striati.
A small ependymal gland of the circumventricular system, located in the dorsocaudal region of the third ventricle.
The lens-shaped nucleus located in the ventral part of the subthalamus on the inner aspect of the internal capsule that is concerned with the integration of somatic motor function.
Multi-tissue structure that is part of the midbrain and develops from the alar plate. It is located dorsal to the lateral tegmentum where it extends into the medial tectal ventricle and receives ascending sensory octavolateralis input.
Cell mass in the caudal and ventral aspect of the dorsal thalamus adjoining the pineal gland.
Nucleus that is located ventrally in the hypothalamus.
Part of the globus pallidus consisting of the more medial of the two segments.
The pallial region located next to the pallium-subpallium boundary.
Nucleus situated in the thalamus that receives inputs from the basal nuclei and the function of which is to help coordinate and plan movement.
Nucleus situated in the thalamus to which somatosensory input is predominantly directed.
A metameric segment of the central nervous system.
A neuromere that is part of the presumptive forebrain.
The 4th segment of the developing forebrain.
The 5th segment of the developing forebrain.
The 6th segment of the developing forebrain.
One of the system of communicating cavities in the brain that are continuous with the central canal of the spinal cord, that are lined with an epithelial ependyma, and that contain cerebral-spinal fluid. The system comprises four ventricles, the right and left lateral ventricles (one for each hemisphere), third ventricle, and fourth ventricle.
A protrusion at the posterior end of the hypothalamus that contains hypothalamic nuclei.
Structure that lies rostral to the area of the tegmentum and that is a site of dopamine-containing cells.
Either of the two brain ventricles that are bilateral (left and right, one for each hemisphere).
Brain ventricle formed by a median cleft in the diencephalon between the two thalami.
A spatially aggregated collection of nerve cell bodies in the CNS, consisting of one or more subpopulations that share cell type, chemical phenotype, and connections, and including nearby cells that share the same cell type, chemical phenotype, and connections.
The lateral ventricle that is located in the left hemisphere of the brain.
The lateral ventricle that is located in the right hemisphere of the brain.
Type of epithelial cell that secretes a macromolecule or ion product. In many epithelia, occasional specialized secretory cells are scattered among other, non-secretory cells.
The bundle of microtubules and associated proteins that forms the core of cilia and is responsible for their movements.
A membrane-tethered, short cylindrical array of microtubules and associated proteins found at the base of a cilium that is similar in structure to a centriole and derives from it. The cilium basal body is the site of assembly and remodelling of the cilium and serves as a nucleation site for axoneme growth.
The ventrolateral regions of the neural tube, above to the floor plate region and encompassing structurally distinct interneurons (in lateral positions) and the more ventral motor neurons.
The dorsolateral regions of the neural tube, ventral to the roof plate region and encompassing structurally distinct sensory neurons (more dorsally) and interneurons (in lateral positions).
The region of presomitic mesoderm that lays immediately adjacent and posetrior to the last formed somite.
The most posterior region of presomitic mesoderm where somitomeres have yet to be fated.
Cranial placode with neurogenic potential.
An epithelial cell that is part of the epidermis.
Compartment of tail somite 18 that is a precursor of muscle.
Compartment of tail somite 18 that is a precursor of the axial skeleton.
Blood vessel that is part of the dorsal fin.
Blood vessel that is part of the ventral fin.
Blood vessel that is part of the ventral blood island.
The erythroid-forming compartment of the ventral blood island.
A tissue whose predominant feature is extracellular matrix that may or may not be highly hydrated or calcified.
Mineralized bone tissue that has terminally differentiated osteoblasts but lacks osteocytes.
An anatomical structure that has more than one cell as a part.
Epithelium that covers the small and large intestine in the larval frog.
Epithelium that covers the small and large intestine in the adult frog.
Spatial concept pertaining to being located on or directed toward the side of the body to the west when facing north.
Astrocyte-like radial glial cell that extends vertically throughout the retina, with the nucleus usually in the middle of the inner nuclear layer.
Specialized protrusion of a cell composed of microtubules and serving a role in intercellular signaling.
Array of microtubules and associated molecules that forms between opposite poles of a cell during mitosis or meiosis and serves to move the duplicated chromosomes apart.
Migrating motile tip of a growing nerve cell axon or dendrite.
A cellular organelle, found close to the nucleus in many cells, consisting of a small cylinder with microtubular walls, 300-500 nm long and 150-250 nm in diameter. It contains nine short, parallel, peripheral microtubular fibrils, each fibril consisting of one complete microtubule fused to two incomplete microtubules. Cells usually have two centrioles, lying at right angles to each other. At division, each pair of centrioles generates another pair and the twin pairs form the pole of the mitotic spindle.
A multisubunit complex that is located at the centromeric region of DNA and provides an attachment point for the spindle microtubules.
The region of a chromosome that is attached to the spindle during nuclear division. It is defined genetically as the region of the chromosome that always segregates at the first division of meiosis; the region of the chromosome in which no crossing over occurs. At the start of M phase, each chromosome consists of two sister chromatids with a constriction at a point which forms the centromere. During late prophase two kinetochores assemble on each centromere, one kinetochore on each sister chromatid.
A structure comprising a core structure and peripheral material from which a microtubule-based structure, such as a spindle apparatus, is organized. Centrosomes occur close to the nucleus during interphase in many cells, though it changes continually during the cell-division cycle.
The long process of a neuron that conducts nerve impulses, usually away from the cell body to the terminals and varicosities, which are sites of storage and release of neurotransmitter.
A neuron projection that has a short, tapering, often branched, morphology, receives and integrates signals from other neurons or from sensory stimuli, and conducts a nerve impulse towards the axon or the cell body. In most neurons, the impulse is conveyed from dendrites to axon via the cell body, but in some types of unipolar neuron, the impulse does not travel via the cell body.
A cell that has a filiform extrusion of the cell surface.
The embryonic right and left aortas that develop in parallel with the heart and gain access to it via the aortic arches. Later the paired dorsal aortic anlagen unite and finally form the unpaired descending aorta of the adult.
A cell that is located in the interstitial space between the seminiferous tubules and produces male androgens.
A type of cell comprising the main structural component of the liver.
A surface structure principally responsible for the production of noxious or toxic secretion with an effect on numerous species of vertebrates. The glands are almost uniformly distributed, on both ventral and dorsal skin.
A sensory epithelium inside the nasal cavity that is responsible for detecting odors.
A mononuclear phagocyte present in a variety of tissues, typically differentiated from monocytes, capable of phagocytosing a variety of extracellular particulate material, including immune complexes, microorganisms, and dead cells.
Embryonic structure that gives rise to a rhombomere.
The part of the brain that is the morphological boundary between the forebrain and midbrain.
Layer of the optic tectum that contains radial glial and other non-neuronal cells.
Layer of the optic tectum that mainly consists of ascending sensory axons and tectal dendrites.
Layer of the optic tectum that consists of tectal somata.
A cell present in the developing central nervous system. It functions as both a precursor cell and as a scaffold to support neuronal migration. Some have a multipotent ability, as they can differentiate into neurons and radial glial cells by asymmetric divisions during the period of embryonic neurogenesis. They occur mainly in the ventricular layer of the tectum and decrease in number as the brain matures.
A cell that, in the early stages of the brain, are generated from the ectoderm-derived neural epithelium and commit to differentiate into either neurons or radial glial cells. It is well known that radial glial cells have distinctive morphological characteristics and can act as neural progenitor cells (NPCs) or neural stem cells (NSCs), in addition to guiding the migration of differentiating neurons in the central nervous system.
A cell that, like a stem cell, has a tendency to differentiate into a specific type of cell, but is already more specific than a stem cell and is pushed to differentiate into its target cell.
A progenitor cell of the nervous system.
Any of a pair of large, easily identifiable, reticulospinal neurons at the level of the ear in the hindbrain. Importantly, they enable the escape reflex. Inner ear vestibular and auditory neurons form synapses on the lateral dendrite of the ipsilateral Mauthner cell, which in turn form synapses on contralateral spinal motor neurons to activate the C-start escape response.
A calcified dermal layer that is found between the stratum spongiosum and the stratum compactum of the skin.
Any of the hematopoietic stem cell derived phagocytic cells that are first observed in the ventral blood island at NF stages 17-18 and at stage 20 begin to migrate over the whole embryo between the epidermis and the mesoderm, completing their migration by stage 25.
A membrane-bounded organelle of in which chromosomes are housed and replicated. In most cells, it contains all of the cell's chromosomes except the organellar chromosomes, and is the site of RNA synthesis and processing. In some specialized cell types, RNA metabolism or DNA replication may be absent.
All of the contents of a cell excluding the plasma membrane and nucleus, but including other subcellular structures.
The anterior (superior) of the two vertically oriented semicircular canals, which are situated at right angles to each other.
The laterally, or horizontally, oriented of the three semicircular canals.
The posterior of the two vertically oriented semicircular canals, which are situated at right angles to each other.
An elongated, spindle-shaped cell that is located between the basal lamina and the plasmalemma of a muscle fiber. These cells are mostly quiescent, but upon activation they divide to produce cells that generate new muscle fibers.
A glial cell that ensheaths axons of neurons in the peripheral nervous system and is necessary for their maintainance and function. Multiple Schwann cells wrap each axon.
Dorsal endoderm that is adjacent to the notochord.
The caudal zone of the tuberal region of the hypothalamus.
The rostral zone of the tuberal region of the hypothalamus.
A series of nuclei forming a column of grey matter embedded in the medulla, through the center of which runs the solitary tract. The solitary tract and nucleus are structures that carry and receive visceral sensation and taste from the facial (VII), glossopharyngeal (IX) and vagus (X) cranial nerves.
The ventral half of the developing neural tube that is the prethalamus.
Cell area that receives signals from the solitary nucleus and transmits signals to the medulla oblongata, spinal cord, amygdala, and hypothalamus.
Hypothalamic region that with the mammillary nuclei forms the mammillary complex.
Medial nucleus of the reticular nucleus of the brain stem.
Superior nucleus of the reticular nucleus of the brain stem.
Inferior nucleus of the reticular nucleus of the brain stem.
A set of septal nuclei comprising the ventral aspect of the forebrain septum.
The dorsal region of the alar hypothalamus.
A structure in the brain consisting of a band of fibers running along the lateral margin of the ventricular surface of the thalamus. Serving as a major output pathway of the amygdala, it runs from its centromedial division to the ventral medial nucleus of the hypothalamus.
Dermal layer containing loose connective tissue and several types of glands.
Dermal layer composed of alternating sheets of parallel fibers.
A type of smooth muscle-like pericyte that abuts and surrounds the filtration capillaries within the glomerulus.
An epithelial cell that is part of the glomus.
An embryonic progenitor cell type that comprises a population that provides the epicardium, the majority of the cardiac interstitium, the coronary vasculature, and possibly some cardiomyocytes.
Part of the double coil of the small intestine, consisting of anti-clockwise loops of intestine proximal to the internal coil.
Part of the double coil of the small intestine, consisting of clockwise loops of intestine distal to the external coil.
Nerve that provides the connection to the nervous system for nearly the whole of the skin of the leg, the muscles of the back of the thigh, and those of the leg and foot.
The location where ganglion cell axons exit the eye to form the optic nerve.
A longitudinal fold of the wall projecting into the cavity of the intestine.
An axon that is part of a motor neuron and which projects outside the spinal cord to directly or indirectly control muscles.
A hindlimb muscle that is used in locomotion and which contains a population of slow or tonic fibers, as well as twitch fibers.
A shallow, longitudinal groove separating the developing gray matter into a basal and alar plates along the length of the neural tube.
A mucous gland that is part of the skin.
A gland in which the principal secretory cells are mucus secreting cells.
A gland of the skin in which some secretory cells are serous and some mucous.
Any of the branched tubuloalveolar glands situated in the mucous membrane of the olfactory region of the nasal cavity that produce mucus to moisten the olfactory epithelium and dissolve odor-containing gases.
A defined region within the ventral telencephalon that gives rise to GABAergic and cholinergic cortical interneurons and is also a source of early-born oligodendrocytes in the telencephalon.
Multinucleate cell formed by later myoblasts that cling by pseudopodia pushed into the surfaces of existing myotubes, and that instead of fusing with the myotube fuse with each other.
Muscle-forming part of each myotome that splits from the ventrolateral edge and gives rise to the epaxial musculature.
Muscle-forming part of each myotome that splits from the dorsomedial edge and gives rise to the hypaxial musculature.
The bilaminar epithelium formed from the myotome and dermatome.
A gelatinous layer that surrounds the oocyte and releases chemoattractants that activate and guide sperm to the oocyte.
A special form of chromosome found in growing oocytes, transforming into the lampbrush form because of an active transcription of many genes, and organized into a series of chromomeres with large chromatin loops extended laterally.
A cell-free extract obtained from oocytes.
Blastomere which lies adjacent to the prospective dorsal midline of the animal hemisphere at the eight-cell stage.
Blastomere which lies adjacent to the prospective dorsal midline of the vegetal hemisphere at the eight-cell stage.
Blastomere which lies adjacent to the prospective ventral midline of the animal hemisphere at the eight-cell stage.
Blastomere which lies adjacent to the prospective ventral midline of the vegetal hemisphere at the eight-cell stage.
Blastomere which lies adjacent to the prospective dorsal midline of the animal hemisphere at the 16-cell stage.
Blastomere which lies in the animal hemisphere lateral to blastomere D1.1 at the 16-cell stage.
Blastomere which lies adjacent to the prospective dorsal midline of the vegetal hemisphere at the 16-cell stage.
Blastomere which lies in the vegetal hemisphere lateral to blastomere D2.1 at the 16-cell stage.
Blastomere which lies adjacent to the prospective ventral midline of the animal hemisphere at the 16-cell stage.
Blastomere which lies in the animal hemisphere lateral to V1.1 at the 16-cell stage.
Blastomere which lies adjacent to the prospective ventral midline of the vegetal hemisphere at the 16-cell stage.
Blastomere which lies in the vegetal hemisphere lateral to V2.1 at the 16-cell stage.
Blastomere which lies adjacent to the prospective dorsal midline in the first tier of blastomeres. It contributes to a variety of tissues and organs, including the cement gland, brain, retina, lens, cranial ganglia, otic vesicle, neural crest, spinal cord, somites, liver, gut and pharynx.
Blastomere which lies adjacent to the prospective dorsal midline, posterior to its sister cell, blastomere D1.1.1, in the second tier of blastomeres. It contributes cells to a variety of tissues and organs, including the stomodeum, retina, epidermis, lens, cranial ganglia, epibranchial placodes, neural crest, brain, spinal cord, gut, liver, pharynx, somites, and archenteron roof.
Blastomere which lies lateral to blastomere D1.1.1 and is in the first tier of blastomeres. It contributes to a variety of tissues and organs, including the cement gland, head epidermis, olfactory epithelium, lens, cranial ganglia, otic vesicle, epidermis, tail fin, neural crest, retina, hindbrain, spinal cord, pharyngeal arches, caudal notochord and hindgut.
Blastomere which lies lateral to blastomere D1.1.2, posterior to its sister cell, blastomere D1.2.1, in the second tier of blastomeres. It contributes to a variety of tissues and organs including fin, epidermis, cement gland, olfactory epithelium, neural crest, lens, cranial ganglia, retina, brain, notochord, somites, pronephric kidney, lateral plate mesoderm, pharynx, foregut, hindgut and archenteron roof.
Blastomere which lies adjacent to the prospective dorsal midline in the fourth tier of blastomeres. It contributes largely to endodermal and mesodermal structures including the branchial and lateral plate mesoderm, foregut, liver, hindgut, some of the trunk, and a small number of cells contributing to neural crest of ectodermal origin.
Blastomere which lies adjacent to the prospective dorsal midline, anterior to its sister cell, blastomere D2.1.1, in the third tier of blastomeres. It contributes to mostly endodermal and mesodermal structures including the heart, head mesenchyme, notochord, somites, lateral plate mesoderm, foregut, hindgut, and a few cells of ectodermal origin (in cranial ganglia and neural crest).
Blastomere which lies lateral to blastomere D2.1.1 in the fourth tier of blastomeres. It contributes cells to the cranial ganglia, neural crest, spinal cord, fin epidermis, branchial mesoderm, heart, somites, pharynx, foregut, liver, and hindgut.
Blastomere which lies lateral to blastomere D2.1.2, anterior to its sister cell, blastomere D2.2.1, in the third tier of blastomeres. It contributes cells to the epidermis, neural crest, brain, spinal cord, head mesoderm, somites, pronephric kidney, lateral plate mesoderm, tail fin mesenchyme, foregut, hindgut, with occasional cells in the liver and proctodeum observed.
Blastomere which lies adjacent to the prospective ventral midline in the first tier of blastomeres. It contributes to epidermal and placodal derivatives including the epidermis, lens, cement gland, cranial ganglia, otic vesicle, neural crest, Rohon-Beard neurons, and spinal cord (but no other CNS structures). It also contributes to the pharyngeal mesoderm, heart, somites, pronephric kidney, lateral plate mesoderm and tail fin mesenchymes, and a few cells in the gut.
Blastomere which lies adjacent to the prospective ventral midline, posterior to its sister cell, blastomere V1.1.1, in the second tier of blastomeres. It contributes to trunk epidermis and neural crest cells, Rohon-Beard neurons, somites, the pronephric kidney, lateral plate mesoderm, tail fin mesenchyme, hindgut and proctodeum.
Blastomere which lies lateral to blastomere V1.1.1 and is in the first tier of blastomeres. It contributes to many ectodermal structures including the epidermis, lens, cranial ganglia, otic vesicle, neural crest, olfactory placode, cement gland, retina, brain, and spinal cord. It also contributes cells to the pharyngeal mesoderm, head mesenchyme, heart, somites, pronephric kidney, lateral plate mesoderm and tail fin mesenchyme, archenteron roof, with occasional cells in the foregut, liver, hindgut and proctodeum.
Blastomere which lies lateral to blastomere V1.1.2, posterior to its sister cell, blastomere V1.2.1, in the second tier of blastomeres. It contributes to the epidermis, fins, cranial ganglia, otic vesicle, central nervous system, neural crest, and somites, with occasional cells in the pharyngeal mesoderm, head mesenchyme, hindgut, and proctodeum.
Blastomere which lies adjacent to the prospective, ventral midline in the fourth tier of blastomeres. It contributes a few cells to the epidermis, neural crest and spinal cord, and a large number of cells to the somites, pronephric kidney, lateral plate mesoderm, tail fin mesenchyme, hindgut, and proctodeum.
Blastomere which lies adjacent to the prospective ventral midline, anterior to its sister cell, blastomere V2.1.1, in the third tier of blastomeres. It contributes cells to the epidermis, neural crest, spinal cord, somites, tail, hindgut and proctodeum.
Blastomere which lies lateral to blastomere V2.1.1, in the fourth tier of blastomeres. It contributes cells to the epidermis and neural crest, spinal cord, somites, foregut, hindgut, and fewer cells to the head, pharyngeal mesoderm and proctodeum.
Blastomere which lies lateral to blastomere V2.1.2, anterior to its sister cell, blastomere V2.2.1, in the third tier of blastomeres. It contributes cells to the epidermis, tail fin, cranial ganglia, neural crest, hindbrain, spinal cord, otic vesicle, pharyngeal mesoderm, somites, foregut, hindgut, archenteron roof, and proctodeum.
Blastomere that is any of blastomeres D2.1 and D2.2 and their children cells after division, D2.1.1, D2.1.2, D2.2.1 and D2.2.2, on the left and right sides of embryo.
Blastomere that is any of blastomeres D1.1 and D1.2 and their children cells after division, D1.1.1, D1.1.2, D1.2.1 and D1.2.2, on the left and right sides of embryo.
Blastomere that is any of blastomeres V2.1 and V2.2 and their children cells after division, V2.1.1, V2.1.2, V2.2.1 and V2.2.2, on the left and right sides of embryo.
Blastomere that is any of blastomeres V1.1 and V1.2 and their children cells after division, V1.1.1, V1.1.2, V1.2.1 and V1.2.2, on the left and right sides of embryo.
A cell in the pituitary gland (hypophysis) that generates melanocyte-stimulating hormone from its precursor polypeptide, pro-opiomelanocortin (POMC).
melanocyte stimulating hormone secreting cell
A characteristic, electrondense germ plasm organelle encapsulating the cytoplasmic face of the nuclear envelope of the cells destined to the germline fate.
Cell component comprising the outer layers of the oocyte.
The irregular network of unit membranes, visible only by electron microscopy, that occurs in the cytoplasm of many eukaryotic cells. The membranes form a complex meshwork of tubular channels, which are often expanded into slitlike cavities called cisternae. The ER takes two forms, rough (or granular), with ribosomes adhering to the outer surface, and smooth (with no ribosomes attached).
Embryonic region which is specified to form the head of the embryo.
Any of the long, generally straight, hollow tubes of internal diameter 12-15 nm and external diameter 24 nm found in a wide variety of eukaryotic cells; each consists (usually) of 13 protofilaments of polymeric tubulin, staggered in such a manner that the tubulin monomers are arranged in a helical pattern on the microtubular surface, and with the alpha/beta axes of the tubulin subunits parallel to the long axis of the tubule; exist in equilibrium with pool of tubulin monomers and can be rapidly assembled or disassembled in response to physiological stimuli; concerned with force generation, e.g. in the spindle.
Cell component comprising the outer layers of the vegetal region of the oocyte.
Embryonic structure that consists of the anterior part of the foregut and develops into the esophagus and trachea.
The section of the stomach comprising the cardia, fundus, and stomach body.
The section of the stomach comprising the antrum and pylorus.
A characteristically star-shaped type of glial cell found in the optic nerve, brain and spinal cord. They have many processes, giving them their star shape, which terminate in structures called end-feet. They are the most numerous glial cell in the central nervous system and can behave like phagocytes in the CNS during metamorphosis.
A class of large neuroglial (macroglial) cells in the central nervous system that form the insulating myelin sheath of axons.
The smallest glial cell type in the central nervous system, cells of this type actively detect inflammatory responses/infection. They transform to a phagocytotic form, actively removing infective agents, and thus can present antigens to immune system cells.
An endocrine cell that is located in the epithelium of the gastrointestinal tract or in the pancreas.
Tissue which during gastrulation involutes into the interior of the embryo, where its deep mesenchymal cells form the notochordal and somitic mesoderm and its superficial epithelial cells form the endodermal roof of the archenteron.
A ciliated cell that has a single cilium.
The cytoplasm beneath the outer layers of the oocyte.
A ciliated cell that has more than one cilium.
A structure derived from the foregut that becomes a lung.
A cartilaginous extension of the stapes that expands into a cartilaginous tympanic disk.
The bony part of the stapes which forms the shaft. It is shaped like a bent rod: its distal half is firmly embedded within the tympanic disk, extending from the disk center caudally and dorsally, turning inwards, until it reaches the oval window at a shallow angle.
A cartilaginous component of the stapes that is firmly attached to the proximal end of the pars media. It lies within the oval window and forms the stapes footplate.
That part of the stapes lying within the oval window, formed from the stapes pars interna.
The section of the stomach which lies between the cardia and the stomach body, and contains the fundic glands.
Entrance to the inner ear in the lateral wall of the otic capsule, which contains the footplate of the stapes.
Cartilaginous extension of the prootic bone which overlies the middle ear region.
A muscle acting to open the lower jaw, which runs from the caudal otic region downwards, passing over the stapes.
Superior aspect of the cranial muscle that passes between the otic capsule and the scapula. It originates on the otic capsule just caudal to the oval window.
Inferior aspect of the cranial muscle that passes between the otic capsule and the scapula. It originates on the otic capsule just caudal to the oval window.
A long, strap-like muscle that originates mainly from the parotic crest, passes over the stapes and ultimately inserts on the ventral surface of the larynx.
A muscle that originates on the otic capsule and adjacent tympanic annulus, and inserts on the pectoral girdle.
The oval shaped cartilaginous ring that supports the cartilaginous tympanic disk.
Anatomical line that divides the archenteron roof into right and left halves.
The section of the stomach which lies between the fundus and the pyloric antrum.
The section of the stomach which lies between the stomach body and pylorus, and that contains gastrin-producing G cells, which stimulate acid production, and the luminal pH-sensitive population of somatostatin-producing D cells.
The stomach tissue region which surrounds and controls the distal outlet of the stomach, which opens into the duodenum, and contains the pyloric glands.
The section of the stomach which is attached to the esophagus and contains the cardiac glands.
A tiny skeletal element adjacent to the anterior-most digit in the autopod in the developing forelimb, possibly representing a vestigal digit.
A tiny skeletal element adjacent to the anterior-most digit in the autopod in the developing hindlimb (i.e., hindlimb digit 5), possibly representing a vestigal 6th digit in Xenopus.
Skeletal subdivision comprising the skeletal elements of the mandibular arch.
A region of the embryo that is located broadly around the heart, but ventral to the pharyngeal region, posterior to the cement gland, and anterior to the endoderm or organs of endodermal origin (foregut, liver and lung primordia).
A type of endocrine cell in the pancreatic islets of the pancreas. They make up some of the islet cells synthesizing and secreting the peptide hormone glucagon, which elevates the glucose levels in the blood.
A type of cell that is found in the pancreatic islets of the pancreas and secretes insulin.
Somatostatin-producing cell that is found in the stomach, intestine and the pancreatic islets.
A type of endocrine cell that is found in the islets of Langerhans and produces the hormone ghrelin.
A type of cell that produces pancreatic polypeptides in the pancreatic islets (the islets of Langerhans) of the pancreas.
A temporal interval that defines Xenopus life from unfertilized egg to adult and death stages.
Nieuwkoop and Faber stage 1, corresponding to an embryo of age 0 hr and having the following external morphological criteria: One cell stage, shortly after fertilization. Pigmentation darker ventrally than dorsally. Length: 1.4 - 1.5 mm.
Tailbud stage that refers to the earlier events associated with this stage, comprising Nieuwkoop and Faber stages 22 to 28.
Embryonic stage during which the solid morula acquires an internal cavity, comprising Nieuwkoop and Faber stages 7 to 9.
Embryonic stage during which the zygote undergoes synchronous divisions into 2, 4, 8, 16, etc. blastomeres, comprising Nieuwkoop and Faber stages 2 to 6.5.
Embryonic stage during which gastrulation takes place, with a proportion of cells migrating below the surface of the embryo to form two inner layers (endoderm and mesoderm) and the cells which remain outside spreading over the whole surface of the embryo to form the ectoderm; comprising Nieuwkoop and Faber stages 10 to 12.5.
Embryonic stage during which the future nervous system appears as a thickened plate in dorsal ectoderm, the plate then rolling up at its sides to form a tube; comprising Nieuwkoop and Faber stages 13 to 21.
Embryonic stage during which neurulation is completed and tail formation begins, visible by an emerging tail primordium; comprising Nieuwkoop and Faber stages 22 to 44 (feeding), including the beginning of hatching (NF stage 35/36).
The post-embryonic Xenopus developmental stage from feeding to the end of metamorphosis, encompassing Weisz's first-form tadpole (equivalent to Nieuwkoop and Faber 45 to 49), second-form tadpole (NF 49 to 56) and third-form tadpole (NF 56 to 60-plus) stages.
Xenopus developmental stage that corresponds to a sexually immature post-tadpole animal.
Nieuwkoop and Faber stage 2, corresponding to an embryo of age 1 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Advanced two cell stage. First cleavage groove has reached vegetal pole. Ventral side of blastomeres darker than dorsal side. Length: 1.4 - 1.5 mm.
Xenopus developmental stage that starts with fertilization and ends with the formed feeding larva.
Nieuwkoop and Faber stage 3, corresponding to an embryo of age 2 hr at 22-24 Celsius and having the following external morphological criteria: Advanced four-cell stage. Second cleavage groove has reached vegetal pole. In animal view dorsal blastomeres usually smaller than ventral ones; the latter darker than the former. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 4, corresponding to an embryo of age 2 hr 15 min at 22-24 Celsius and having the following external morphological criteria: Advanced eight cell stage. Dorsal micro- and macromeres usually smaller than ventral ones; dorsal micromeres less pigmented than ventral ones. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 5, corresponding to an embryo of age 2 hr 45 min at 22-24 Celsius and having the following external morphological criteria: Advanced sixteen cell stage. Dorsal micromeres distinctly smaller and less pigmented than ventral ones. Macromeres entirely separated by cleavage grooves. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 6, corresponding to an embryo of age 3 hr at 22-24 Celsius and having the following external morphological criteria: Advanced thirty-two cell stage. Distinction between dorsal and ventral micromeres as in preceding stage. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 7 (64-cell stage), corresponding to an embryo of age 4 hr at 22-24 Celsius and having the following external morphological criteria: Large-cell blastula stage. In animal view about 10 micromeres along meridian. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 8 (128-cell stage), corresponding to an embryo of age 5 hr at 22-24 Celsius and having the following external morphological criteria: Medium-cell blastula stage. Surface not yet entirely smooth. Border of animal pigment cap more diffuse at dorsal than at lateral and ventral sides. Gradual transition in cell size from animal to vegetative pole. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 9, corresponding to an embryo of age 7 hr at 22-24 Celsius and having the following external morphological criteria: Fine-cell blastula stage. Animal cells smaller at dorsal than at ventral side. Border between marginal zone and vegetative field distinct, particularly dorsally, owing to difference in cell size. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 10, corresponding to an embryo of age 9 hr at 22-24 Celsius and having the following external morphological criteria: Initial gastrula stage. First indication of blastopore only by pigment concentration. No formation of groove. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 11, corresponding to an embryo of age 11 hr 45 min at 22-24 Celsius and having the following external morphological criteria: Horse-shoe-shaped blastopore stage. Blastopore groove surrounding about half of future yolk plug and indicated at its ventral side; future yolk plug often rounded rectangular, slightly elongated in dorso-ventral direction, diameter more than two-fifths of diameter of egg (plus or minus 50 degrees of circumference). Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 12, corresponding to an embryo of age 13 hr 15 min at 22-24 Celsius and having the following external morphological criteria: Medium yolk plug stage. Yolk plug circular; diameter somewhat less than one fourth of diameter of egg (plus or minus 25 degrees). More and less pigmented fields radiating from yolk plug. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 13, corresponding to an embryo of age 14 hr 45 min at 22-24 Celsius and having the following external morphological criteria: Slit-blastopore stage. Neural plate faintly delimited; slight elevation of its rostral part and slight flattening of its caudal part. Caudal part of median groove formed. Length: 1.5 - 1.6 mm.
Nieuwkoop and Faber stage 14, corresponding to an embryo of age 16 hr 15 min at 22-24 Celsius and having the following external morphological criteria: Neural plate stage. Cerebral part of neural plate bent downwards, with median elevation at rostral end of median groove. Initial elevation of neural folds, most pronounced in future nucal region. Blastopore always slit-shaped. Length: 1.5 - 1.6 mm.
Nieuwkoop and Faber stage 15, corresponding to an embryo of age 17 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Early neural fold stage. Presumptive cement gland faintly circumscribed. Anterior part of neural plate roundish. Neural folds distinct, except medio-rostrally; initial formation of sharp inner ridges on neural folds in rhombencephalic region. Length: 1.5 - 1.6 mm.
Nieuwkoop and Faber stage 16, corresponding to an embryo of age 18 hr 15 min at 22-24 Celsius and having the following external morphological criteria: Mid neural fold stage. Anterior part of neural plate rectangular; darkly pigmented eye anlagen present; neural plate sharply constricted in the middle. Inner ridges on neural folds forming angle of about 90 degrees with neural plate in rhombencephalic region. Length: 1.5 - 1.6 mm.
Nieuwkoop and Faber stage 17, corresponding to an embryo of age 18 hr 45 min at 22-24 Celsius and having the following external morphological criteria: Late neural fold stage. Anterior part of neural plate oblong triangular, angles formed by eye anlagen. Neural folds approaching each other from blastopore up to anterior trunk region. Length: 1.5 - 1.6 mm.
Nieuwkoop and Faber stage 2-, corresponding to an embryo of age 1 hr 15 min at 22-24 Celsius and having the following external morphological criteria: Beginning of first cleavage. First cleavage groove has not yet reached vegetal pole. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 6.5, corresponding to an embryo of age 3 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Morula stage. About 48 blastomeres. In animal view about 6 micromeres along meridian. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 10.25, corresponding to an embryo of age 10 hr at 22-24 Celsius and having the following external morphological criteria: Early gastrula stage. First formation of dorsal blastopore groove; the groove is still straight. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 10.5, corresponding to an embryo of age 11 hr at 22-24 Celsius and having the following external morphological criteria: Crescent-shaped blastopore stage. Blastopore groove angular. Vegetal field slightly decreased in size, ventral border of future yolk plug indicated by pigment contraction. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 11.5, corresponding to an embryo of age 12 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Large yolk plug stage. Blastopore groove closed ventrally; yolk plug not yet quite circular. At ventral side concentrated superficial pigment still visible. Diameter of yolk plug about a third of diameter of egg (plus or minus 40 degrees). Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 12.5, corresponding to an embryo of age 14 hr 15 min at 22-24 Celsius and having the following external morphological criteria: Small yolk plug stage. Future position of neural plate and median groove indicated by darker pigment lines. Yolk plug usually ovoid, variable in size. Length: 1.4 - 1.5 mm.
Nieuwkoop and Faber stage 18, corresponding to an embryo of age 19 hr 45 min at 22-24 Celsius and having the following external morphological criteria: Neural groove stage. Anterior part of neural plate narrow, more or less club-shaped, often narrower towards rostral end. Parallel neural folds in trunk region very close to each other, not yet touching. Length: 1.5 - 1.6 mm.
Nieuwkoop and Faber stage 19, corresponding to an embryo of age 20 hr 45 min at 22-24 Celsius and having the following external morphological criteria: Initial neural tube stage. Neural folds touching each other, except for inconstant openings at anterior and posterior end and behind nucal region. Considerable lateral extension of brain. Lateral outline of embryo still convex. Length: 1.5 - 1.6 mm.
Nieuwkoop and Faber stage 20, corresponding to an embryo of age 21 hr 45 min at 22-24 Celsius and having the following external morphological criteria: Neural folds fused, suture still present. The two eye anlagen showing through dumb-bell-shaped, eyes hardly protruding. Beginning of stretching of embryos. Lateral outline flat. Length: 1.7 - 1.8 mm.
Nieuwkoop and Faber stage 21, corresponding to an embryo of age 22 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Suture of neural tube completely closed. Delimitation of frontal field by pigment lines. Primary eye vesicles showing through in the form of two separate, obliquely placed oval spots; beginning of protrusion of eyes. Lateral outline of embryo just becoming concave, ventral outline flat. Length: 1.9 - 2.0 mm.
Nieuwkoop and Faber stage 22, corresponding to an embryo of age 24 hr at 22-24 Celsius and having the following external morphological criteria: Distinct protrusion of eyes. Initial groove between jaw- and gill-areas only at latero-dorsal side. Lateral and ventral outlines of embryo slightly concave. Anal opening displaced to ventral side. Vitelline membrane becoming wider. Length: 2.0 - 2.2 mm.
Nieuwkoop and Faber stage 23, corresponding to an embryo of age 1 day, 45 min at 22-24 Celsius and having the following external morphological criteria: Jaw- and gill-areas completely separated by groove. Ventral outline of embryo more concave. Length: 2.2 - 2.4 mm.
Nieuwkoop and Faber stage 24, corresponding to an embryo of age 1 day, 2 hr 15 min at 22-24 Celsius and having the following external morphological criteria: Eyes protruding less far laterally than gill-area. Gill-area more prominent than jaw-area, gill-area not yet grooved. Ventral outline of embryo nicked. Tail bud discernible. Initial motor reactions to external stimulation. Length: 2.5 - 2.7 mm.
Nieuwkoop and Faber stage 25, corresponding to an embryo of age 1 day, 3 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Eyes protruding equally far or further laterally than gill-area. Gill-area grooved. Invagination of otic vesicle indicated by pigment spot. Beginning of fin formation. Length: 2.8 - 3.0 mm.
Nieuwkoop and Faber stage 26, corresponding to an embryo of age 1 day, 5 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Otic vesicle protruding. Pronephros distinctly visible. Myotomes showing through for the first time. Fin somewhat broadened at dorso-caudal end of body. Beginning of spontaneous movements. Length: 3.0 - 3.3 mm.
Nieuwkoop and Faber stage 27, corresponding to an embryo of age 1 day, 7 hr 15 min at 22-24 Celsius and having the following external morphological criteria: Lateral flattening of eyes. Fin transluscent, except for region behind anus. Tail bud formation accentuated in lateral outline. Length: 3.4 - 3.7 mm.
Nieuwkoop and Faber stage 28, corresponding to an embryo of age 1 day, 8 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Fin extending up to anus. Fin broadened and distinctly divided into outer transparent and inner translucent band. Length: 3.8 - 4.0 mm.
Nieuwkoop and Faber stage 29/30, corresponding to an embryo of age 1 day, 11 hr at 22-24 Celsius and having the following external morphological criteria: Gray eye cup showing through for the first time. Fin transparent up to the base over its whole length. Tail bud distinct. Length: 4.0 - 4.5 mm.
Nieuwkoop and Faber stage 31, corresponding to an embryo of age 1 day, 13 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Tail bud equally long as broad. Length: 4.2 - 4.8 mm.
Nieuwkoop and Faber stage 32, corresponding to an embryo of age 1 day, 16 hr at 22-24 Celsius and having the following external morphological criteria: Eye cup horse-shoe-shaped, standing out distinctly. Length of tail bud about 1.5 times its breadth. Length: 4.5 - 5.1 mm.
Nieuwkoop and Faber stage 33/34, corresponding to an embryo of age 1 day, 20 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Stomodeal invagination a shallow vertical groove. Dorsal part of eye more pigmented than ventral part; distinct melanophores in dorsal part. Melanophores appearing dorsally on the head and laterally in a row extending from just below the pronephros backwards. Length of tail bud about twice its breadth. Beginning of heart beat. Length: 4.7 - 5.3 mm.
Nieuwkoop and Faber stage 35/36, corresponding to an embryo of age 2 days, 2 hr at 22-24 Celsius and having the following external morphological criteria: Stomodeal invagination roundish. Eye entirely black, choroid fissure nearly closed. Formation of two gill rudiments, anterior one nipple-shaped. Melanophores appearing on back. Posterior outline of proctodeum still curved. Length of tail bud about three times its breadth. Beginning of hatching. Length: 5.3 - 6.0 mm.
Nieuwkoop and Faber stage 37/38, corresponding to an embryo of age 2 days, 5 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Stomodeal invagination much deeper, opening round. Both gill rudiments nipple-shaped, a branch of the anterior one indicated. Posterior outline of proctodeum straight, forming very obtuse angle with ventral border of tail myotomes. Melanophores spreading over tail. Length: 5.6 - 6.2 mm.
Nieuwkoop and Faber stage 39, corresponding to an embryo of age 2 days, 8 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Melanophores appearing around nasal pits. Opening of stomodeal invagination transversely elongated. Melanophores on back arranged in a superficial and a deeper layer. Outlines of proctodeum and tail myotomes forming angle of about 135 degrees. Melanophores appearing along ventral edge of tail musculature. Length: 5.9 - 6.5 mm.
Nieuwkoop and Faber stage 40, corresponding to an embryo of age 2 days, 18 hr at 22-24 Celsius and having the following external morphological criteria: Mouth broken through. Length of gills about twice their breadth, posterior one sometimes also showing a branch. Outlines of proctodeum and tail myotomes forming angles of 90 degrees. Beginning of blood circulation in gills. Length: 6.3 - 6.8 mm.
Nieuwkoop and Faber stage 41, corresponding to an embryo of age 3 days, 4 hr at 22-24 Celsius and having the following external morphological criteria: Gills broader and flatter, more laterally directed. Formation of a left-rostral and a right-caudal furrow in yolk mass; torsion of interjacent part about 45 degrees; formation of conical proctodeum, forming angle of about 60 degrees with tail myotomes. Formation of fin rostral to proctodeum; ventral outline of yolk mass and proctodeum a smooth concave line. Length: 6.7 - 7.5 mm.
Nieuwkoop and Faber stage 42, corresponding to an embryo of age 3 days, 8 hr at 22-24 Celsius and having the following external morphological criteria: Beginning of formation of opercular folds. Torsion of intestine about 90 degrees; proctodeum connected with yolk mass by short horizontal intestinal tube. Length: 7.0 - 7.7 mm.
Nieuwkoop and Faber stage 43, corresponding to an embryo of age 3 days, 15 hr at 22-24 Celsius and having the following external morphological criteria: Lateral line system becoming visible externally. Cement gland losing its pigment. Torsion of intestine about 180 degrees; proctodeum narrower, arched or S-shaped. Length: 7.5 - 8.3 mm.
Nieuwkoop and Faber stage 44, corresponding to an embryo of age 3 days, 20 hr at 22-24 Celsius and having the following external morphological criteria: Appearance of tentacle rudiments. Opercular folds protruding further. Coiling part of intestine showing S-shaped loop; torsion about 360 degrees. Blood-circulation in gills usually ceased (gills smaller). Length: 7.8 - 8.5 mm.
Nieuwkoop and Faber stage 45, corresponding to a tadpole of age 4 days, 2 hr at 22-24 Celsius and having the following external morphological criteria: Operculum partly covering gills, edge still straight. Intestine spiralized in ventral aspects, showing 1.5 revolutions. Beginning of feeding. Length: 8 - 10 mm.
Nieuwkoop and Faber stage 46, corresponding to a tadpole of age 4 days, 10 hr at 22-24 Celsius and having the following external morphological criteria: Edge of operculum becoming convex. Xantophores appearing on eye and abdomen. Intestine showing 2 to 2.5 revolutions. Hindlimb bud visible for the first time. Length: 9 - 12 mm.
Nieuwkoop and Faber stage 47, corresponding to a tadpole of age 5 days, 12 hr at 22-24 Celsius and having the following external morphological criteria: Tentacles larger. Edge of operculum forming quarter of a circle. Xantophores forming opaque layer on abdomen. Intestine showing 2.5 to 3.5 revolutions. Hindlimb bud more distinct. Length: 12 - 15 mm.
Nieuwkoop and Faber stage 48, corresponding to a tadpole of age 7.5 days at 22-24 Celsius and having the following external morphological criteria: Beginning of pigmentation around n. acusticus. Forelimb bud visible for the first time. Shining gold-coloured abdomen. Hindlimb bud semicircular in lateral aspect. Length: 14 - 17 mm.
Nieuwkoop and Faber stage 49, corresponding to a tadpole of age about 12 days at 22-24 Celsius and having the following external morphological criteria: Melanophores usually appearing around thymus gland and nerves and blood vessels of head; xantophores appearing on pericard. Forelimb bud distinct. Hindlimb bud somewhat longer, distal outline still circular, no constrictions at base. Melanophores appearing on dorsal and ventral fin. Length: 17 - 23 mm.
Nieuwkoop and Faber stage 50, corresponding to a tadpole of age about 15 days at 22-24 Celsius and having the following external morphological criteria: Forelimb bud somewhat oval-shaped in dorsal aspect. Hindlimb bud longer than broad, constricted at base, distal outline somewhat conical. Length: 20 - 27 mm.
Nieuwkoop and Faber stage 51, corresponding to a tadpole of age about 17 days at 22-24 Celsius and having the following external morphological criteria: Tentacles much longer. Forelimb bud oval-shaped in lateral aspect. Hindlimb bud conical in shape, its length about 1.5 times its breadth; melanophores appearing on it. Length: 28 - 36 mm.
Nieuwkoop and Faber stage 52, corresponding to a tadpole of age about 21 days at 22-24 Celsius and having the following external morphological criteria: Forelimb bud irregularly conical. Hindlimb bud showing first indication of ankle constriction and first sign of flattening of foot. Length: 42 - 56 mm.
Nieuwkoop and Faber stage 53, corresponding to a tadpole of age about 24 days at 22-24 Celsius and having the following external morphological criteria: Fore- and hindlimbs in paddle stage. Hindlimb whithout foot somewhat longer than broad; 4th and 5th toe indicated. Length: 50 - 60 mm.
Nieuwkoop and Faber stage 54, corresponding to a tadpole of age about 26 days at 22-24 Celsius and having the following external morphological criteria: All four fingers indicated; edge of hand slightly scalloped between fingers; melanophores appearing on forelimb. Length of hindlimb without foot nearly twice its breadth; all five toes indicated, the second only very slightly. Length: 58 - 65 mm.
Nieuwkoop and Faber stage 55, corresponding to a tadpole of age about 32 days at 22-24 Celsius and having the following external morphological criteria: Hand pronated about 90 degrees; free parts of fingers about equally long as broad. Length of hindlimb without foot about 3 times its breadth; length of cartilages of 4th and 5th toe about 4 times their breadth. Length: 70 - 80 mm.
Nieuwkoop and Faber stage 56, corresponding to a tadpole of age about 38 days at 22-24 Celsius and having the following external morphological criteria: Elbow and wrist clearly indicated; length of free parts of fingers 3 to 4 times their breadth. Length of cartilages of 4th and 5th toe about 6 times their breadth. Length: 70 - 100 mm.
Nieuwkoop and Faber stage 57, corresponding to a tadpole of age about 41 days at 22-24 Celsius and having the following external morphological criteria: Pigment-free spot appearing above "Stirnorgan". Angle of elbow more than 90 degrees; fingers stretched out in forelimb atrium, their length about 7 times their breadth. Length: 75 - 105 mm.
Nieuwkoop and Faber stage 58, corresponding to a tadpole of age about 44 days at 22-24 Celsius and having the following external morphological criteria: Forelimbs broken through. Guanophores appearing on abdomen and thighs (adult skin areas). All three claws present on hindlimbs. Length: 80 - 110 mm.
Nieuwkoop and Faber stage 59, corresponding to a tadpole of age about 45 days at 22-24 Celsius and having the following external morphological criteria: Tentacles beginning to shrivel up. Stretched forelimb reaching down to base of hindlimb. Guanophores appearing near base of forelimb (adult skin area); anterior border of adult skin area on abdomen not yet sharp; appearance of irregular dark spots on back.
Nieuwkoop and Faber stage 60, corresponding to a tadpole of age about 46 days at 22-24 Celsius and having the following external morphological criteria: N. olfactorius still longer than bulbus olfactorius. Guanophores appearing on lower jaw (adult skin area). Openings of gill chambers still wide. Distal half of fingers of stretched forelimb extending beyond base of hindlimb; forelimb still situated behind level of heart. Adult skin area of base of forelimb covered with guanophores; anterior border of adult skin area on abdomen sharper, reaching up to heart.
Nieuwkoop and Faber stage 61, corresponding to a tadpole of age about 48 days at 22-24 Celsius and having the following external morphological criteria: Head narrower. Tentacles considerably shortened, mostly curved backwards. Length of n. olfactorius equal to diameter of bulbus olfactorius. 4th arterial arch seen just in front of adult skin area of forelimb. Openings of gill chambers considerably narrowed. Forelimb at level of posterior half of heart. Adult skin area on abdomen covering posterior half of heart. Fins considerably reduced.
Nieuwkoop and Faber stage 62, corresponding to a tadpole of age about 49 days at 22-24 Celsius and having the following external morphological criteria: Head still somewhat broader than cranial part of trunk. Tentacles short, straight. N. olfactorius shorter than diameter of bulbus olfactorius. Corner of mouth still in front of eye. Thymus gland somewhat protruding. 3rd arterial arch ("larval aorta") seen at distance of its own diameter in front of adult skin area of forelimb. Opening of operculum reduced to curved slit. Forelimb at level of middle of heart. Anterior border of adult skin area on abdomen entirely sharp, mostly nicked medially. Ventral fin disappeared from abdomen.
Nieuwkoop and Faber stage 63, corresponding to a tadpole of age about 51 days at 22-24 Celsius and having the following external morphological criteria: Head narrower than trunk. Tentacles mostly disappeared. Corner of mouth at level of caudal border of eye. "Larval aorta" and thymus gland no longer externally visible. Operculum closed. Adult skin areas on abdomen and lower jaw separated by narrow band of larval skin. Forelimb at level of anterior half of heart. Fin mostly perforated near anus. Tail still slightly longer than body.
Nieuwkoop and Faber stage 64, corresponding to a tadpole of age about 53 days at 22-24 Celsius and having the following external morphological criteria: Corner of mouth well behind eye. Various adult skin areas joined almost everywhere, borderlines still clearly visible. Length of tail (from anus) is a third of body length.
Nieuwkoop and Faber stage 65, corresponding to a tadpole of age about 54 days at 22-24 Celsius and having the following external morphological criteria: Borderlines between adult skin areas partly disappeared. Tail oblong triangular in dorsal aspect, length abouth one tenth of body length.
Nieuwkoop and Faber stage 66, corresponding to a tadpole of age about 58 days at 22-24 Celsius and having the following external morphological criteria: Border lines between adult skin areas disappeared. Tail only a very small triangle, no longer visible from ventral side.
Tadpole stage during which toe differentiation and rapid hindlimb growth continue, followed by tail resorption; comprising Nieuwkoop and Faber stages 54 to 66.
Tailbud stage that refers to the later events associated with this stage, comprising Nieuwkoop and Faber stages 29/30 to 44.
Unspecified Xenopus developmental stage.
Any of the stages of the developing or mature Xenopus female gamete.
The pre-vitellogenic stage of the developing female gamete.
The early vitellogenic stage of the developing female gamete.
The mid-vitellogenic stage of the developing female gamete.
The stage of the developing female gamete that corresponds to the establishment of polarization along the animal-vegetal axis of the gamete.
The late-vitellogenic stage of the developing female gamete.
The developmental stage of the female gamete at which the gamete is fully grown.
Tadpole stage during which limb bud growth occurs, comprising Nieuwkoop and Faber stages 45 to 54.
Metamorphosing tadpole stage during which toe differentiation and rapid hindlimb growth continue, comprising Nieuwkoop and Faber stages 55 to 57.
Metamorphosing tadpole stage during which tail resorption occurs, comprising Nieuwkoop and Faber stages 58 to 66.
The developmental stage of the female gamete at which the gamete has reached maturity.
Xenopus developmental stage that corresponds to a fully formed, mature animal.
Xenopus developmental stage that is one of the 66 standard chronological embryonic and tadpole stages originally described by Nieuwkoop and Faber in the Normal Table of Xenopus laevis (Daudin).
Xenopus developmental stage that succeeds the embryonic stage.