as part of embryonic development the neural tube will become the
central nervous system
1669418
Neural tube In the developing chordate (including vertebrates), the neural tube is the embryonic precursor to the central nervous system, which is made up of the brain and spinal cord. The neural groove gradually deepens as the neural folds become elevated, and ultimately the folds meet and coalesce in the middle line and convert the groove into the closed neural tube. In humans, neural tube closure usually occurs by the fourth week of pregnancy (28th day after conception). The ectodermal wall of the tube forms the rudiment of the nervous system. The centre of the tube is the "neural canal".
Neural tube
3863079
during embryonic development. This is where the neural plate folds in on itself, forming the neural crest. Neural crest cells will eventually become portions of the peripheral nervous system. During development, the neural tube will considered the precursore to the spinal cord and the rest of the nervous system, eventually becoming the Central Nervous System. The central nervous system can be divided into three classes of neuromeres: prosomeres, mesomeres, and rhombomeres. The forebrain forms the six prosomers, p1 to p6, which are then divided into two more categories, dorsal and ventral. The telencephalon forms from the dorsal parts of p6
Neuromere
1669418
Neural tube In the developing chordate (including vertebrates), the neural tube is the embryonic precursor to the central nervous system, which is made up of the brain and spinal cord. The neural groove gradually deepens as the neural folds become elevated, and ultimately the folds meet and coalesce in the middle line and convert the groove into the closed neural tube. In humans, neural tube closure usually occurs by the fourth week of pregnancy (28th day after conception). The ectodermal wall of the tube forms the rudiment of the nervous system. The centre of the tube is the "neural canal".
Neural tube
11151526
of Sox2 results in neural malformities and eventually fetal death, further underlining Sox2’s vital role in embryonic development. In neurogenesis, Sox2 is expressed throughout developing cells in the neural tube as well as in proliferating central nervous system progenitors. However, Sox2 is downregulated during progenitors' final cell cycle during differentiation when they become post mitotic. Cells expressing Sox2 are capable of both producing cells identical to themselves and differentiated neural cell types, two necessary hallmarks of stem cells. Proliferation of Sox2+ neural stem cells can generate neural precursors as well as Sox2+ neural stem cell population. Induced pluripotency is possible
SOX2
1669425
Shh in the ventral end. This was shown using zebrafish mutants that had varying amounts of BMP signaling activity. Researchers observed changes in dorsal-ventral patterning, for example zebrafish deficient in certain BMPs showed a loss of dorsal sensory neurons and an expansion of interneurons. Neural tube In the developing chordate (including vertebrates), the neural tube is the embryonic precursor to the central nervous system, which is made up of the brain and spinal cord. The neural groove gradually deepens as the neural folds become elevated, and ultimately the folds meet and coalesce in the middle line and convert the groove
Neural tube
7457380
Neuroepithelial cell Neuroepithelial cells are the "stem cells" of the nervous system, deriving from pluripotent stem cells in several different stages of neural development. These neural Stem cells differentiate further into multiple types of cells, like neurons, astrocytes and other glial cells. They appear during embryonic development of the neural tube as well as in adult neurogenesis in specific areas of the central nervous system. They are also associated with several neurodegenerative diseases. These cells have often been called neuroblasts in an effort to delineate them as precursors to neurons and glial cells. During the third week of embryonic growth
Neuroepithelial cell
19183164
mitosis), and many will live the lifetime of the animal. During embryonic development, the mammalian central nervous system (CNS; brain and spinal cord) is derived from the neural tube, which contains NSCs that will later generate neurons. However, neurogenesis doesn't begin until a sufficient population of NSCs has been achieved. These early stem cells are called neuroepithelial cells (NEC)s, but soon take on a highly elongated radial morphology and are then known as radial glial cells (RGC)s. RGCs are the primary stem cells of the mammalian CNS, and reside in the embryonic ventricular zone, which lies adjacent to the central
Neurogenesis
376607
the embryo specializes as 'neurectoderm', which will become the future central nervous system. Later in development, neurulation causes the neurectoderm to form the neural tube. At the neural tube stage, the anterior portion undergoes encephalization to generate or 'pattern' the basic form of the brain. At this stage of development, the principal cell type of the CNS is considered a neural stem cell. These neural stem cells are pluripotent, as they can generate a large diversity of many different neuron types, each with unique gene expression, morphological, and functional characteristics. The process of generating neurons from stem cells is called
Stem cell
19336733
the proper pharyngeal segmental identities. Furthermore, "Brpf1" may not only has significant role for maintaining the anterior-posterior axis of the craniofacial skeleton, but also the dorsal-ventral axis of the caudal skeleton. Recent studies have shown that ablation of the mouse "Brpf1" gene causes embryonic lethality at embryonic day 9.5. Specifically, "Brpf1" regulates placenta vascular formation, neural tube closure, primitive hematopoiesis and embryonic fibroblast proliferation. For the central nervous system, "Brpf1" has high expression and is essential for the development of several important structures, including neocortex and dentate gyrus in the hippocampus. "Brpf1" is dynamically expressed during forebrain development, especially the
Brpf1
2099265
each give rise to a particular set of cells. The neural tube cells will become the central nervous system, neural crest cells will become the peripheral and enteric nervous system, along with melanocytes, facial cartilage and the dentin of teeth, and the epidermal cell region will give rise to epidermis, hair, nails, sebaceous glands, olfactory and mouth epithelium, as well as eyes. Neurulation proceeds by primary and secondary neurulation, both positioning neural crest cells between a superficial epidermal layer and a deep neural tube. During primary neurulation, the notochord cells of the mesoderm signal the adjacent, superficial ectoderm cells to
Ectoderm
4109344
neural tube. Splits or pockets may form in the germinal sheet of cells forming vesicles or elongations. The lungs and glands of the organism may develop this way. A primary step in organogenesis for chordates is the development of the notochord, which induces the formation of the neural plate, and ultimately the neural tube In vertebrate development, the development of the neural tube will give rise to the brain and spinal cord. Vertebrates develop a neural crest that differentiates into many structures, including bones, muscles, and components of the central nervous system. Differentiation of the ectoderm into the neural crest,
Organogenesis
11303246
Neuraxis The neuraxis or sometimes neuroaxis is the axis of the central nervous system. It denotes the direction in which the central nervous system lies. During embryological development, the neuraxis is bent by various flexures, contributing to the mature structure of the brain and spinal cord. Embryonic development can help in understanding the structure of the adult brain because it establishes a framework on which more complex structures can be built. First, the neural tube establishes the anterior–posterior dimension of the nervous system, which is called the neuraxis. The embryonic nervous system in mammals can be said to have a
Neuraxis
14440107
24. giving rise to the lamina terminalis of the brain. Rostral neuropore The rostral neuropore or anterior neuropore is a region corresponding to the opening of the embryonic neural tube in the anterior portion of the developing prosencephalon. The central nervous system develops from the neural tube, which initially starts as a plate of cells in the ectoderm and this is called the neural plate, the neural plate then undergoes folding and starts closing from the center of the developing fetus, this leads to two open ends, one situated cranially/rostrally and the other caudally. Bending of the neural plate begins
Rostral neuropore
14440106
Rostral neuropore The rostral neuropore or anterior neuropore is a region corresponding to the opening of the embryonic neural tube in the anterior portion of the developing prosencephalon. The central nervous system develops from the neural tube, which initially starts as a plate of cells in the ectoderm and this is called the neural plate, the neural plate then undergoes folding and starts closing from the center of the developing fetus, this leads to two open ends, one situated cranially/rostrally and the other caudally. Bending of the neural plate begins on day 22, and the cranial neuropore closes on day
Rostral neuropore
17625072
DNA lesions was necessary for the proper recruitment of the two canonical PRC1 complexes (cPRC1.2 and cPRC1.4), defined by their PCGF subunits, MEL18 and BMI1 respectively. Therefore, recruitment of the ncPRC1.1 complex represents an early and critical regulatory step in homologous recombination repair. Loss of KDM2B leads to severe developmental defects (growth defects in the brain, including failure of neural tube closure and craniofacial malformations, hematopoietic development) leading to embryonic lethality KDM2B The human KDM2B gene encodes the protein Lysine (K)-specific demethylase 2B. KDM2B is broadly and highly expressed in embryonic tissues (especially in the developing central nervous system of
KDM2B
94100
affect the transformation of the overlying ectoderm into nervous tissue. The neural tube, forming from the ectoderm, contains CSF prior to the development of the choroid plexuses. The open neuropores of the neural tube close after the first month of development, and CSF pressure gradually increases. As the brain develops, by the fourth week of embryological development three swellings have formed within the embryo around the canal, near where the head will develop. These swellings represent different components of the central nervous system: the prosencephalon, mesencephalon and rhombencephalon. Subarachnoid spaces are first evident around the 32nd day of development near
Cerebrospinal fluid
11303248
brain stem, and at the top of the neck, that animal would be looking straight up instead of straight in front. Neuraxis The neuraxis or sometimes neuroaxis is the axis of the central nervous system. It denotes the direction in which the central nervous system lies. During embryological development, the neuraxis is bent by various flexures, contributing to the mature structure of the brain and spinal cord. Embryonic development can help in understanding the structure of the adult brain because it establishes a framework on which more complex structures can be built. First, the neural tube establishes the anterior–posterior dimension
Neuraxis
3850823
Rhombomere In the vertebrate embryo, a rhombomere is a transiently divided segment of the developing neural tube, within the hindbrain region (a neuromere) in the area that will eventually become the rhombencephalon. The rhombomeres appear as a series of slightly constricted swellings in the neural tube, caudal to the cephalic flexure. In human embryonic development, the rhombomeres are present by day 29. In the early developmental stages of the neural tube, segmentation of the neuroepithelium occurs. This segmentation turns into a series of neuromeres. Each segment is called a rhombomere. Every rhombomere develops its own set of ganglia and nerves.
Rhombomere
3850843
from different species after the rhombomeres have been grafted on, which could lead to the contamination of one rhombomeric region with another, most likely from the neighboring rhombomeres. Rhombomere In the vertebrate embryo, a rhombomere is a transiently divided segment of the developing neural tube, within the hindbrain region (a neuromere) in the area that will eventually become the rhombencephalon. The rhombomeres appear as a series of slightly constricted swellings in the neural tube, caudal to the cephalic flexure. In human embryonic development, the rhombomeres are present by day 29. In the early developmental stages of the neural tube, segmentation
Rhombomere
6865903
that protein lead to opposite conditions such as cyclopia where facial features are insufficiently developed. Healthy brain development is also dependent on the signaling function of SHH. During embryonic development, SHH directs embryonic cells to organize in specific areas that later become specialized neural tissues, thus controlling the size and shape of brain structures. Diprosopus often occurs in combination with other congenital disorders, particularly anencephaly, neural tube defect and cardiac malformations. When present, the brain may show abnormalities ranging from partial to complete duplication of brain structures, and/or underdevelopment of brain tissues. Most human infants with diprosopus are stillborn. Known
Diprosopus
5043640
neurula stage embryo depending on the species. For example, in reptiles, extra-embryonic membrane tissues become distinct from the embryo. The neurula embryo has five regions of mesoderm that surround the neural tube. Anterior mesoderm develops into the head region, while posterior mesoderm develops into the trunk. Various molecules, including proteoglycans in the extracellular matrix, and genes, including Pax transcription factors, are essential for the development and closure of the neural tube in the neurula stage embryo. Neurulation is a process in vertebrate embryos at the neurula stage in which the neural tube is formed. There are two types of neurulation:
Neurula
20408922
become determined to be the inner cell mass. All the other activity, such as changes in gene expression, signalling proteins, release of morphogens, and epigenetic changes, are considered the result of differentiation after the response of the cytoskeleton to mechanical signals which then determines cell fate using purely mechanical signals. Failure of neural tube closure is explained as a failure of methylation of cytoskeleton of developing neural tissue for those neural tube defects which are folate sensitive and prevented by folic acid supplementation. Embryonic differentiation waves A mechanochemical based model for primary neural induction was first proposed in 1985 by
Embryonic differentiation waves
133098
certain features in embryonic development are conserved and palingenetic, while others are caenogenetic. Caenogenesis represents “the blurring of ancestral resemblances in development,” which are said to be the result of certain adaptations to embryonic life due to environmental changes. In his drawings, Haeckel cites the notochord, pharyngeal arches and clefts, pronephros and neural tube as palingenetic features. However, the yolk sac, extra-embryonic membranes, egg membranes and endocardial tube are considered caenogenetic features. The addition of terminal adult stages and the telescoping, or driving back, of such stages to descendant's embryonic stages are likewise representative of Haeckelian embryonic development. In addressing
Embryo drawing
9380278
Otic vesicle Otic vesicle, or auditory vesicle, consists of either of the two sac-like invaginations formed and subsequently closed off during embryonic development. It is part of the neural ectoderm, which will develop into the membranous labyrinth of the inner ear. This labyrinth is a continuous epithelium, giving rise to the vestibular system and auditory components of the inner ear. During the earlier stages of embryogenesis, the otic placode invaginates to produce the otic cup. Thereafter, the otic cup closes off, creating the otic vesicle. Once formed, the otic vesicle will reside next to the neural tube medially, and on
Otic vesicle
19797668
early vesicle stages, the walls of the neural tube contain neural stem cells in a region called the neuroepithelium or ventricular zone. These neural stem cells divide rapidly, driving growth of the early brain, but later, these stem cells begin to generate neurons through the process of neurogenesis. Brain vesicle Brain vesicles are the bulge-like features of the early development of the neural tube in vertebrates. Vesicle formation begins shortly after anterior neural tube closure at about embryonic day 9.0 in the mouse and the fourth and fifth gestational week in human development. In zebrafish and chicken embryos, brain vesicles
Brain vesicle
1773725
Anencephaly Anencephaly is the absence of a major portion of the brain, skull, and scalp that occurs during embryonic development. It is a cephalic disorder that results from a neural tube defect that occurs when the rostral (head) end of the neural tube fails to close, usually between the 23rd and 26th day following conception. Strictly speaking, the Greek term translates as "no in-head" (that is, totally lacking the inside part of the head, i.e. the brain), but it is accepted that children born with this disorder usually only lack a telencephalon, the largest part of the brain consisting mainly
Anencephaly
3095779
neurogenesis. Placodes are transient, focal aggregations of ectoderm located in the developmental region of future vertebrate head, and give rise to sensory organs. Early cranial sensory placodes are marked by expression of Six1, part of the Six family of transcription factors that regulate preplacodal ectoderm specification. The olfactory placode forms as two thickenings of non-neural region of embryonic ectoderm. In mice, the olfactory placode derives from an anterior portion of the neural tube, ~9-9.5 days into development and not long after the closure of the neural plate. Development of the olfactory placode requires the presence underlying neural crest-derived mesenchymal tissue.
Olfactory epithelium
11317167
linking Drp1 to apoptosis and cancer. Several studies have indicated that Drp1 is essential for proper embryonic development. Drp1 knockout mice exhibit abnormal brain development and die around embryonic day 12. In neural specific Drp1 knockout mice, brain size is reduced and apoptosis is increased. Synapse formation and neurite growth are also impaired. A second group of researchers generated another neural specific knockout mouse line. They found that knocking out Drp1 resulted in the appearance of large mitochondria in Purkinje cells and prevented neural tube formation. In humans, loss of Drp1 function affects brain development and is also associated with
DNM1L
17672633
embryos they died due to impairment of neural tube development. DNMT3a silencing did not cause embryonic lethality, but did result in a severe detriment in postnatal neurogenesis. This is largely due to the timing in which these epigenetic mechanisms are active. DNMT3b is expressed in early neural progenitor cells and decrease as neural development proceeds and DNMT3a is barely detectable up until embryonic day 10 (E.10). However, at E.10, DNMT3a expression increases significantly from E13.5 and well into adulthood. In the postnatal forebrain, DNMT3a is expressed in the subventricular zone (SVZ) and the hippocampal dentate gyrus, the primary locations for
Epigenetic regulation of neurogenesis
12964548
the spinal cord enlarges: The spinal cord is made from part of the neural tube during development. There are four stages of the spinal cord that arises from the neural tube: The neural plate, neural fold, neural tube, and the spinal cord. Neural differentiation occurs within the spinal cord portion of the tube. As the neural tube begins to develop, the notochord begins to secrete a factor known as Sonic hedgehog or SHH. As a result, the floor plate then also begins to secrete SHH, and this will induce the basal plate to develop motor neurons. During the maturation of
Spinal cord
3849987
of the notochodral cells become incorporated into the center section neural plate to later form the floor plate of the neural tube. The notochord plate separates and forms the solid notochord. The folding of the neural tube to form an actual tube does not occur all at once. Instead, it begins approximately at the level of the fourth somite at Carnegie stage 9 (around Embryonic day 20 in humans). The lateral edges of the neural plate touch in the midline and join together. This continues both cranially (toward the head) and caudally (toward the tail). The openings that are formed
Neurulation
12314128
nervous system (brain and spinal cord). Throughout a period of a few short days, the neural tube becomes closed off and three chambers develop towards the anterior portion of the neural tube [2]. These chambers are known as the ventricles, and the tissue that surrounds them constitutes the three major sections of the brain: the forebrain, midbrain, and hindbrain. The telencephalon, the embryonic structure from which the mature cerebrum develops, resides in the forebrain. In development from the neural tube to the brain, which weighs approximately three pounds and contains billions of neurons, the cerebral cortex forms from the inside
Telencephalization
44905
mammals departs from it to some degree, in a way that reflects in part the complexity of their behavior. For example, primates have brains 5 to 10 times larger than the formula predicts. Predators tend to have larger brains than their prey, relative to body size. All vertebrate brains share a common underlying form, which appears most clearly during early stages of embryonic development. In its earliest form, the brain appears as three swellings at the front end of the neural tube; these swellings eventually become the forebrain, midbrain, and hindbrain (the prosencephalon, mesencephalon, and rhombencephalon, respectively). At the earliest
Brain
4551091
anterior end of the embryonic disk, where they are continuous with each other, and from there gradually extend backward, one on either side of the anterior end of the primitive streak. Between these folds is a shallow median groove, the neural groove. The groove gradually deepens as the neural folds become elevated, and ultimately the folds meet and coalesce in the middle line and convert the groove into a closed tube, the neural tube or canal, the ectodermal wall of which forms the rudiment of the nervous system. After the coalescence of the neural folds over the anterior end of
Embryogenesis
690280
develops from the most anterior part of the neural plate, a specialized part of the embryonic ectoderm. The neural plate folds and closes to form the neural tube. From the cavity inside the neural tube develops the ventricular system, and, from the epithelial cells of its walls, the neurons and glia of the nervous system. The most anterior (front, or cranial) part of the neural plate, the prosencephalon, which is evident before neurulation begins, gives rise to the cerebral hemispheres and its later cortex. Cortical neurons are generated within the ventricular zone, next to the ventricles. At first, this zone
Cerebral cortex
6981339
Dermoid sinus Dermoid sinus is a thought to be a genetic skin condition in dogs. It is also known as "pilonidal sinus". However, unlike pilonidal sinus in humans, the dermoid sinus in dogs is a neural tube defect. Dermoid sinus is sometimes also confused with dermoid cyst (a teratoma). A dermoid sinus is rare in dogs and cats. It can appear as single or multiple lumps on the dorsal midline. The sinus is caused in the embryonic stage of development. In normal development, the neural tube from which the spine develops separates from the skin. In the case of a
Dermoid sinus
7681382
Neural fold The neural fold is a structure that arises during neurulation in the embryonic development of both birds and mammals among other organisms. This structure is associated with primary neurulation, meaning that it forms by the coming together of tissue layers, rather than a clustering, and subsequent hollowing out, of individual cells (known as secondary neurulation). In humans, the neural folds are responsible for the formation of the anterior end of the neural tube. The neural folds are derived from the neural plate, a preliminary structure consisting of elongated ectoderm cells. The folds give rise to neural crest cells,
Neural fold
7824937
bilaminar embryonic disc becomes trilaminar. The notochord forms thereafter. Through the process of neurulation, the notochord induces the formation of the neural tube in the embryonic disc. Embryonic disc The floor of the amniotic cavity is formed by the embryonic disc (or embryonic disk) composed of a layer of prismatic cells, the embryonic ectoderm, derived from the inner cell-mass and lying in apposition with the endoderm. In humans, it is the stage of development that occurs after implantation and prior to the embryonic folding (e.g. seen between about day 14 to day 21 post fertilization). It is derived from the
Embryonic disc
3346683
Diencephalon The diencephalon is a division of the forebrain (embryonic "prosencephalon"), and is situated between the telencephalon and the midbrain (embryonic "mesencephalon"). It consists of structures that are on either side of the third ventricle, including the thalamus, the hypothalamus, the epithalamus and the subthalamus. The diencephalon is one of the main vesicles of the brain formed during embryogenesis. During the third week of development a neural tube is created from the ectoderm, one of the three primary germ layers. The tube forms three main vesicles during the third week of development: the prosencephalon, the mesencephalon and the rhombencephalon. The
Diencephalon
8457410
with the extraembryonic layer, forming the chorion (contributing to the blood supply). At the same time during embryonic development, the ectoderm begins to thicken and fold upward, forming the neural folds, which eventually meet to form the neural tube and neural crest. Because these two events occur at roughly the same time in embryological development, abnormalities found in this syndrome can involve not only the ectodermal cells, but also disruption to development in the mesectodermal layer constituted by the neural crest. "What these structures have in common is that their development and morphogenesis depends on the signaling between specialized ectodermal
Ectrodactyly–ectodermal dysplasia–cleft syndrome
8893847
during the early tailbud stage (see image), via a poorly defined mechanism of induction. During normal development, after neural tube closure, the pigment precursors align dorsally along the anterior-posterior axis of the neural tube. Whichever cell aligns anteriorly will become the otolith, while the posterior cell will form the ocellus. In the absence of cell-cell interactions both cells develop into ocelli, which is the default fate. To elucidate whether the fates of the otolith and ocellus are determined in the early embryo or after the precursors align during neural tube closure, ablation and drug treatment techniques were used in the
Equivalence group
19797667
Brain vesicle Brain vesicles are the bulge-like features of the early development of the neural tube in vertebrates. Vesicle formation begins shortly after anterior neural tube closure at about embryonic day 9.0 in the mouse and the fourth and fifth gestational week in human development. In zebrafish and chicken embryos, brain vesicles form by about 24 hours and 48 hours post-conception, respectively. Initially there are three primary brain vesicles: prosencephalon, mesencephalon, and rhombencephalon. These develop into five secondary brain vesicles – the prosencephalon is subdivided into the telencephalon and diencephalon, and the rhombencephalon into the metencephalon and myelencephalon. During these
Brain vesicle
3429471
from bone, dermatome which will form skin of the back and myotome which will form muscle. The somites that remain close to the neural tube at the back of the body have epaxial myotome, whilst the somites that migrate to the midline have hypaxial myotome. The hypaxial myotome forms the abdominal muscles. The myotome cells will give rise to myoblasts (embryonic progenitor cells) which will align to form myotubules and then muscle fibres. Consequently, the myotome will become three muscle sheets that form the layers of abdominal wall muscles. The muscle of concern for exomphalos is the rectus abdominis. In
Omphalocele
15541319
midline to form the primitive heart tube, which will eventually develop into the histologically definitive endocardium. The myocardium forms from mesoderm cells surrounding the heart tube, while the epicardium develops from other cells, most likely from neural crest cells. Endocardial tubes The endocardial tubes are paired regions in the embryo that appear in its ventral pole by the middle of the third week of gestation and consist of precursor cells for the development of the embryonic heart. The endocardial heart tubes derive from the visceral mesoderm and initially are formed by a confluence of angioblastic blood vessels on either side
Endocardial tubes
7457381
the brain begins to develop in the early fetus in a process called induction. Neuroepithelial cells of the ectoderm begin multiplying rapidly and fold in forming the neural plate, which invaginates during the fourth week of embryonic growth and forms the neural tube. The formation of the neural tube polarizes the neuroepithelial cells by orienting the apical side of the cell to face inward, which later becomes the ventricular zone, and the basal side is oriented outward, which contacts the pial, or outer surface of the developing brain. As part of this polarity, neuroepithelial cells express prominin-1 in the apical
Neuroepithelial cell
19378525
processes such as vesicle trafficking, cell movement and cytoskeletal assembly, a very few studies have been reported for their role in neuronal development. PIP5K is highly expressed kinase in the nervous system of several organisms and plays important role in neuronal development including embryogenesis and post-natal neural development. The disruption of PIP5KIγ leads to broad developmental and cellular defects in mice indicating PIP5KIγ plays critical role for embryogenesis and adulthood of mice and its disruption causes fatality for postnatal life []. The embryo without PIP5KIγ has extensive prenatal lethality during embryonic development. The disruption of PIP5KIγ also causes neural tube
Phosphatidylinositol-4-phosphate 5- kinases (PIP5K) in neuronal development
6255857
transition. Amphioxus forms an epithelial neural tube and dorsal notochord but does not have the EMT potential of the primitive streak. In higher chordates, the mesenchyme originates out of the primitive streak migrates anteriorly to form the somites and participate with neural crest mesenchyme in formation of the heart mesoderm. In vertebrates, epithelium and mesenchyme are the basic tissue phenotypes. During embryonic development, migratory neural crest cells are generated by EMT involving the epithelial cells of the neuroectoderm. As a result, these cells dissociate from neural folds, gain motility, and disseminate to various parts of the embryo, where they differentiate
Epithelial–mesenchymal transition
7681392
for the rest of his or her life. Depending on the severity and the affected area, individuals can experience a variety of symptoms, including a varying motor function and mobility, bladder control, and/or sexual function. If the failure is instead in the cranial neuropore, anencephaly occurs. In this condition, the brain tissue is directly exposed to the amniotic fluid, and is subsequently degraded. If the entire neural tube fails to close, the condition is referred to as craniorachischisis. Neural fold The neural fold is a structure that arises during neurulation in the embryonic development of both birds and mammals among
Neural fold
1957822
fluid The structures of the ventricular system are embryologically derived from the neural canal, the centre of the neural tube. As the part of the primitive neural tube that will develop into the brainstem, the neural canal expands dorsally and laterally, creating the fourth ventricle, whereas the neural canal that does not expand and remains the same at the level of the midbrain superior to the fourth ventricle forms the cerebral aqueduct. The fourth ventricle narrows at the obex (in the caudal medulla), to become the central canal of the spinal cord. In more detail, around the third week of
Ventricular system
4594496
create the neural tube. The figure demonstrates the development of the neural plate into the neural tube, which is where the neural crest cells are derived from as well. In primary neurulation, the layer of ectoderm divides into three sets of cells: the neural tube (future brain and spinal cord), epidermis (skin), and neural crest cells (connects epidermis and neural tube and will migrate to make neurons, glia, and skin cell pigmentation). During the stage of neural plate formation the embryo consists of three cell layers: the ectoderm that eventually forms the skin and neural tissues, the mesoderm that forms
Neural plate
6625885
occurs, suggesting that the Fpn1 protein encoded is necessary and essential for normal embryonic development. Fpn1 is expressed in the syncytiotrophoblast cells in the placenta and visceral endoderm of mice at E7.5. Further, several retrospective studies have noted an increased incidence of spina bifida occurring after low maternal intake of iron during embryonic and fetal development. A study examining the consequences of several different mutations of the "Slc40a1" mouse gene suggested that several serious neural tube and patterning defects were produced as a result, including spina bifida, exencephaly, and forebrain truncations, among others. Given the findings of studies to date,
Ferroportin
7118620
the fetus. The overall perinatal mortality after open surgery has been estimated to be approximately 6%, according to a study in the United States 2003. All future pregnancies for the mother require cesarean delivery because of the hysterotomy. However, there is no presented data suggesting decreased fertility for the mother. Neural tube defects(NTD), which begin to become observable at the 28th day of pregnancy, occur when the embryonic neural tube fails to close properly, the developing brain and spinal cord are openly exposed to amniotic fluid and with this, causes the nervous system tissue to break down. Prenatal repair of
Fetal surgery
17987620
of the Hox gene "labial (lab)". Like the Hox genes, "vnd" is required for specification along the dorsoventral axis. Mutant "vnd" produce the loss of tritocerebral neural lineages as well as neuromeres, therefore this gene is crucial for the development of these cell lineages. Without proper "vnd" expression throughout Drosophila embryonic development, the brain would not become functional. Ventral nervous system defective The ventral nervous system defective (vnd) gene present in fruit flies of the genus Drosophila functions during embryonic brain development and is necessary for the formation and specification of neural cell lineages. This transcription factor is expressed in
Ventral nervous system defective
1669420
during the fourth week in humans. Improper closure of the neuropores can result in neural tube defects such as anencephaly or spina bifida. The dorsal part of the neural tube contains the alar plate, which is associated primarily with . The ventral part of the neural tube contains the basal plate, which is primarily associated with motor (i.e., muscle) control. The neural tube patterns along the dorsal-ventral axis to establish defined compartments of neural progenitor cells that lead to distinct classes of neurons. According to the French flag model of morphogenesis, this patterning occurs early in development and results from
Neural tube
20030233
spreads into the "Gbx2" expressing hindbrain, it leads to serotonergic neuron differentiation. Later on in embryonic development, "Fgf8" expression localizes to the rostral most "Gbx2" expressing cells (caudal region of the MHB) in the neural tube. "Wnt1" is mainly expressed in the entire midbrain ("Otx2" expressing cells) at first. Once the midbrain/hindbrain boundary has formed, "Wnt1" expression localizes to the roof plate of the neural tube and to the posterior region of the midbrain. At the MHB, Wnt1 plays a role in cell proliferation and also maintains the "FGF8" expression. The transcription factor "En1" is expressed in the MHB. In
Isthmic organizer
1293022
critical step in wound healing. Fragmenting fibronectin further exposes its V-region, which contains the site for α4β1 integrin binding. These fragments of fibronectin are believed to enhance the binding of α4β1 integrin-expressing cells, allowing them to adhere to and forcefully contract the surrounding matrix. Fibronectin is necessary for embryogenesis, and inactivating the gene for fibronectin results in early embryonic lethality. Fibronectin is important for guiding cell attachment and migration during embryonic development. In mammalian development, the absence of fibronectin leads to defects in mesodermal, neural tube, and vascular development. Similarly, the absence of a normal fibronectin matrix in developing amphibians
Fibronectin
10345491
band of neural precursors that develops a slit like lumen to eventually become the neural tube. The neural tube begins as a solid cord formed from the ectoderm. This cord then sinks into the embryo and becomes hollow, forming the neural tube. This process contrasts with the process in other chordates, which occurs by an infolding of the ectoderm to form a hollow tube. Throughout the years advances in research have shown that neural formation relies on interactions between extrinsic signaling factors and intrinsic transcription factors. Extrinsic signals involved are BMP, Wnt, and FGF and intrinsic transcription factors like SoxB1
Fish development
11094029
folds of this groove close to create the neural tube (this form of neurulation is called primary neurulation). The ventral (front) part of the neural tube is called the basal plate; the dorsal (rear) part is called the alar plate. The hollow interior is called the neural canal. By the end of the fourth week of gestation, the open ends of the neural tube (the neuropores) close off. The spinal cord forms from the lower part of the neural tube. The wall of the neural tube consists of neuroepithelial cells, which differentiate into neuroblasts, forming the mantle layer (the gray
Development of the nervous system in humans
17680945
cells of which Perisynaptic Schwann cells are a subset. Neural crest cells are found in the dorsal neural tube from which nerves and glia alike grow and Neural crest cells are the precursors to many various tissue types including enteric neurons and glia. Schwann cell precursors (a first derivative of Neural crest cells) are present as the nerve axon grows from the dorsal neural tube, but it has been shown that these glial precursors are not essential to axonal growth. The transition from neural crest cells to Schwann cell precursors is characterized by Sox10 and generally occurs around embryonic day
Perisynaptic schwann cells
1576817
levels, and social cues, rather than to simply mimic their environment. During vertebrate embryonic development, chromatophores are one of a number of cell types generated in the neural crest, a paired strip of cells arising at the margins of the neural tube. These cells have the ability to migrate long distances, allowing chromatophores to populate many organs of the body, including the skin, eye, ear, and brain. Fish melanophores and iridophores have been found to contain the smooth muscle regulatory proteins [calponin] and caldesmon. Leaving the neural crest in waves, chromatophores take either a dorsolateral route through the dermis, entering
Chromatophore
3379947
sequential divisions. Neuroblast A neuroblast or primitive nerve cell is a postmitotic cell that does not divide further and which will develop into a neuron after a migration phase. Neuroblasts differentiate from neural stem cells and are committed to become neurons. Neuroblasts are mainly present as precursors of neurons during embryonic development; however, they also constitute one of the cell types involved in adult neurogenesis. Adult neurogenesis is characterized by neural stem cell differentiation and integration in the mature adult mammalian brain. This process occurs in the dentate gyrus of the hippocampus and in the subventricular zones of the adult
Neuroblast
3379941
Neuroblast A neuroblast or primitive nerve cell is a postmitotic cell that does not divide further and which will develop into a neuron after a migration phase. Neuroblasts differentiate from neural stem cells and are committed to become neurons. Neuroblasts are mainly present as precursors of neurons during embryonic development; however, they also constitute one of the cell types involved in adult neurogenesis. Adult neurogenesis is characterized by neural stem cell differentiation and integration in the mature adult mammalian brain. This process occurs in the dentate gyrus of the hippocampus and in the subventricular zones of the adult mammalian brain.
Neuroblast
3849994
limbs of the vertebrate ). Masses of tissue called the neural crest that are located at the very edges of the lateral plates of the folding neural tube separate from the neural tube and migrate to become a variety of different but important cells. Neural crest cells will migrate through the embryo and will give rise to several cell populations, including pigment cells and the cells of the peripheral nervous system. Failure of neurulation, especially failure of closure of the neural tube are among the most common and disabling birth defects in humans, occurring in roughly 1 in every 500
Neurulation
6225011
had been released up to that time) collectively as number 20 on their "Top 100 Games of All Time", calling them "the zeitgeist of the 16-bit era". In December 2006, IGN ranked "Sonic the Hedgehog" as the 19th greatest series of all time, claiming that "although recent 3D entries in the series have been somewhat lacking, there is no denying the power of this franchise." Neuroscientists studying the development of the embryonic neural system named a specific set of proteins, in charge of the differentiation of neural tube cells, after the main character of the game franchise. A common criticism
Sonic the Hedgehog
5752139
Myelencephalon The myelencephalon or afterbrain is the most posterior region of the embryonic hindbrain, from which the medulla oblongata develops. During fetal development, divisions of the neural tube that give rise to the hindbrain (rhombencephalon) and the other primary vesicles (forebrain and midbrain) occur at just 28 days after conception. With the exception of the midbrain, these primary vesicles undergo further differentiation at 5 weeks after conception to form the myelencephalon and the other secondary vesicles. Final shape differentiation of the myelencephalon into the medulla oblongata can be observed at 20 weeks gestation. The medulla oblongata is part of the
Myelencephalon
849209
and the thalamus (dorsal thalamus). The development of the thalamus can be subdivided into three steps. The thalamus is the largest structure deriving from the embryonic diencephalon, the posterior part of the forebrain situated between the midbrain and the cerebrum. After neurulation the anlage of the prethalamus and the thalamus is induced within the neural tube. Data from different vertebrate model organisms support a model in which the interaction between two transcription factors, Fez and Otx, are of decisive importance. Fez is expressed in the prethalamus, and functional experiments show that Fez is required for prethalamus formation. Posteriorly, Otx1 and
Thalamus
2698501
aren't (the pars reticulata), which serve a different role from one another within the basal ganglia system. The substantia nigra has extremely high production of melanin (hence the colour), dopamine, and noradrenalin; the loss of dopamine producing neurons in this region contributes to the progression of Parkinson's disease. During embryonic development, the midbrain (also known as the mesencephalon) arises from the second vesicle of the neural tube, while the interior of this portion of the tube becomes the cerebral aqueduct. Unlike the other two vesicles - the forebrain and hindbrain - the midbrain does not develop further subdivision for the
Midbrain
7602937
Alar plate The alar plate (or alar lamina) is a neural structure in the embryonic nervous system, part of the dorsal side of neural tube, that involves the communication of general somatic and general visceral sensory impulses. The caudal part later becomes sensory axon part of the spinal cord. The alar plate specifically later on becomes the dorsal gray of the spinal cord, and develops into the sensory nuclei of cranial nerves V, VII, VIII, IX, and X. The inferior olivary nucleus, mesencephalic nucleus of V, and main sensory nucleus of V are also developed from this plate. Also from
Alar plate
7602938
the rhombic lip of the alar plate develops the cerebellum, which is considered to be a big exception since alar plate gives rise to sensory derivatives only. Alar plate The alar plate (or alar lamina) is a neural structure in the embryonic nervous system, part of the dorsal side of neural tube, that involves the communication of general somatic and general visceral sensory impulses. The caudal part later becomes sensory axon part of the spinal cord. The alar plate specifically later on becomes the dorsal gray of the spinal cord, and develops into the sensory nuclei of cranial nerves V,
Alar plate
5319348
of a smaller cranium. The human brain undergoes gyrification during fetal and neonatal development. In embryonic development, all mammalian brains begin as smooth structures derived from the neural tube. A cerebral cortex without surface convolutions is lissencephalic, meaning 'smooth-brained'. As development continues, gyri and sulci begin to take shape on the fetal brain, with deepening indentations and ridges developing on the surface of the cortex. Changes in the structure of gyri in the cerebral cortex are associated with various diseases and disorders. Pachygyria, lissencephaly, and polymicrogyria are all the results of abnormal cell migration associated with a disorganized cellular architecture,
Gyrus
8074837
in the developing embryo. It is released from the notochord and regulates bone morphogenic protein (BMP4) during development. The absence of BMP4 will cause the patterning of the neural tube and somites from the neural plate in the developing embryo. It also causes formation of the head and other dorsal structures. Noggin function is required for correct nervous system, somite, and skeletal development. Experiments in mice have shown that noggin also plays a role in learning, cognition, bone development, and neural tube fusion. Heterozygous missense mutations in the noggin gene can cause deformities such as joint fusions and syndromes such
Noggin (protein)
11435744
2 (PRC2). Intracellular mechanisms underlying these interactions remain largely unknown. In search of developmentally important genes, Jarid2 has previously been identified by gene trap technology as an important factor necessary for organ development. During mouse organogenesis, Jarid2 is involved in the formation of the neural tube and development of the liver, spleen, thymus and cardiovascular system. Continuous Jarid2 expression in the tissues of the heart, highlight its presiding role in the development of both the embryonic and the adult heart. Mutant models of Jarid2 embryos show severe heart malformations, ventricular septal defects, noncompaction of the ventricular wall, and dilated atria.
JARID2
4551100
cephalic region. At some point after the different germ layers are defined, organogenesis begins. The first stage in vertebrates is called neurulation, where the neural plate folds forming the neural tube (see above). Other common organs or structures that arise at this time include the heart and somites (also above), but from now on embryogenesis follows no common pattern among the different taxa of the animal kingdom. In most animals organogenesis, along with morphogenesis, results in a larva. The hatching of the larva, which must then undergo metamorphosis, marks the end of embryonic development. Embryogenesis Embryogenesis is the process by
Embryogenesis
5270781
Neural crest Neural crest cells are a temporary group of cells unique to chordates of the group Cristozoa that arise from the embryonic ectoderm cell layer, and in turn give rise to a diverse cell lineage—including melanocytes, craniofacial cartilage and bone, smooth muscle, peripheral and enteric neurons and glia. After gastrulation, neural crest cells are specified at the border of the neural plate and the non-neural ectoderm. During neurulation, the borders of the neural plate, also known as the neural folds, converge at the dorsal midline to form the neural tube. Subsequently, neural crest cells from the roof plate of
Neural crest
4594494
cord development. This process as a whole is termed primary neurulation. Signaling proteins are also important in neural plate development, and aid in differentiating the tissue destined to become the neural plate. Examples of such proteins include bone morphogenetic proteins and cadherins. Expression of these proteins is essential to neural plate folding and subsequent neural tube formation. Generally divided into four steps, the process of primary neurulation involves the neural plate in the first three. The formation and folding of the neural plate is the first step in primary neurulation. This is followed by the refinement and growth of neural
Neural plate
1575121
and diffuse into the overlying ectoderm to inhibit the activity of BMP4. This inhibition of BMP4 causes the cells to differentiate into neural cells. Inhibition of TGF-β and BMP (bone morphogenetic protein) signaling can efficiently induce neural tissue from human pluripotent stem cells, a model of early human development. Late in the fourth week, the superior part of the neural tube flexes at the level of the future midbrain—the mesencephalon. Above the mesencephalon is the prosencephalon (future forebrain) and beneath it is the rhombencephalon (future hindbrain). The optical vesicle (which eventually become the optic nerve, retina and iris) forms at
Development of the nervous system
20867365
and rats. Glufosinate-ammonium has also been shown to cause birth defects in mice by interfering with early embryonic brain, and neural tube development. Exposure to Glufosinate in fetuses has been shown to impair the development of glutamate receptors in the brain. Ill effects of consuming DMH - 11 products are major concern. Protesters of DMH - 11 cite the adverse health implications of genetically modified crops, as the case with GM corn which came to light through the Seralini affair, as a reason not to approve DMH - 11 for widespread cultivation and consumption. A major reason for opposition against
DMH-11 Mustard
4594500
begin the shape changes in MHP cells. These cells will decrease in height and become wedge-shaped. Another type of hinge point occurs dorsal-laterally, referred to as dorsal-lateral hinge point (DLHP). These regions furrow and change shape in the same way as MHP cells do before connecting together to form the neural tube. It was seen in an experiment that without the notochord, the MHP characteristics did not develop correctly, so the neural plate and neural tube formation did not happen properly. The communication between the neural plate and the notochord is important for the future induction and formation of the
Neural plate
1575123
pathway to become neural tissue. Evidence for this comes from single, cultured cells of ectoderm, which go on to form neural tissue. This is postulated to be because of a lack of BMPs, which are blocked by the organiser. The organiser may produce molecules such as follistatin, noggin and chordin that inhibit BMPs. The ventral neural tube is patterned by sonic hedgehog (Shh) from the notochord, which acts as the inducing tissue. Notochord-derived Shh signals to the floor plate, and induces Shh expression in the floor plate. Floor plate-derived Shh subsequently signals to other cells in the neural tube, and
Development of the nervous system
1575111
anterior part of the neural tube forms a series of bulges called vesicles, which become the primary anatomical regions of the brain: the forebrain (prosencephalon), midbrain (mesencephalon), and hindbrain (rhombencephalon). These simple, early vesicles enlarge and further divide into the telencephalon (future cerebral cortex and basal ganglia), diencephalon (future thalamus and hypothalamus), mesencephalon (future colliculi), metencephalon (future pons and cerebellum), and myelencephalon (future medulla). The CSF-filled central chamber is continuous from the telencephalon to the spinal cord, and constitutes the developing ventricular system of the CNS. Because the neural tube gives rise to the brain and spinal cord any mutations
Development of the nervous system
1774612
to develop into the cervical vertebrae; the next twelve pairs will form the thoracic vertebrae; the next five pairs the lumbar vertebrae and by about day 29 the sacral somites will appear to develop into the sacral vertebrae; finally on day 30 the last three pairs will form the coccyx. The congenital disorder, spina bifida, occurs as a result of a defective embryonic neural tube, characterised by the incomplete closure of vertebral arch or of the incomplete closure of the surface of the vertebral canal. The most common sites for spina bifida malformations are the lumbar and sacral areas. Another
Sacrum
2900343
BMP7 is crucial for kidney development, sperm synthesis, and neural tube polarization. Both BMP4 and BMP7 regulate mature ligand stability and processing, including degrading ligands in lysosomes. BMPs act by diffusing from the cells that create them. Growth factor and clotting factors are paracrine signaling agents. The local action of growth factor signaling plays an especially important role in the development of tissues. Also, retinoic acid, the active form of vitamin A, functions in a paracrine fashion to regulate gene expression during embryonic development in higher animals. In insects, Allatostatin controls growth though paracrine action on the corpora allata. In
Paracrine signaling
1575119
neural tube is called the basal plate; the dorsal part is called the alar plate. The hollow interior is called the neural canal. By the end of the fourth week of gestation, the open ends of the neural tube, called the neuropores, close off. A transplanted blastopore lip can convert ectoderm into neural tissue and is said to have an inductive effect. Neural inducers are molecules that can induce the expression of neural genes in ectoderm explants without inducing mesodermal genes as well. Neural induction is often studied in xenopus embryos since they have a simple body pattern and there
Development of the nervous system
3346684
prosencephlon gradually divides into the telencephalon and the diencephalon. The diencephalon consists of the following structures: The optic nerve (CNII) attaches to the diencephalon. The optic nerve is a sensory (afferent) nerve responsible for vision; it runs from the eye through the optic canal in the skull and attaches to the diencephalon. The retina itself is derived from the optic cup, a part of the embryonic diencephalon. The diencephalon is the region of the embryonic vertebrate neural tube that gives rise to anterior forebrain structures including the thalamus, hypothalamus, posterior portion of the pituitary gland, and pineal gland. The diencephalon
Diencephalon
2708439
blood–brain barrier, but facilitates the transport of different substances into the brain due to the distinct structural characteristics between the two barrier systems. At the beginning of the third week of development, the embryonic ectoderm forms a thickened strip called the neural plate. By the fourth week of development the neural plate has widened to give a broad cephalic end, a less broad middle part and a narrow caudal end. These swellings represent the beginnings of the forebrain, midbrain and hindbrain. Neural crest cells (derived from the ectoderm) populate the lateral edges of the plate at the neural folds. In
Human brain
507174
between adjacent embryonic tissues, in particular the neural tube, notochord, surface ectoderm and the somitic compartments themselves. The correct specification of the deriving tissues, skeletal, cartilage, endothelia and connective tissue is achieved by a sequence of morphogenic changes of the paraxial mesoderm, leading to the three transitory somitic compartments: dermomyotome, myotome and sclerotome. These structures are specified from dorsal to ventral and from medial to lateral. each somite will form its own sclerotome that will differentiate into the tendon cartilage and bone component. Its myotome will form the muscle component and the dermatome that will form the dermis of the
Mesoderm
11441141
Repulsive guidance molecule A Repulsive guidance molecule A (RGMa) is a bone morphogenetic protein (BMP) co-receptor of the repulsive guidance molecule family. Together with BMPR1A and BMPR1B, as well as ACVR2A and BMPR2, it binds BMPs thereby activating the intracellular SMAD1/5/8 signalling pathway. In humans this protein is encoded by the "RGMA" gene. RGMa is a repulsive guidance molecule for retinal axons. Furthermore, neogenin functions as a receptor for RGM. Neogenin overexpression and RGM downexpression in the developing embryonic neural tube induces apoptosis. The apoptotic activity of neogenin in the neural tube is associated with cleavage of its cytoplasmic domain
Repulsive guidance molecule A
1575118
notochord. Ectodermal cells overlying the notochord develop into the neural plate in response to a diffusible signal produced by the notochord. The remainder of the ectoderm gives rise to the epidermis (skin). The ability of the mesoderm to convert the overlying ectoderm into neural tissue is called neural induction. The neural plate folds outwards during the third week of gestation to form the neural groove. Beginning in the future neck region, the neural folds of this groove close to create the neural tube. The formation of the neural tube from the ectoderm is called neurulation. The ventral part of the
Development of the nervous system
9211538
Mesoderm contributes to the following structures: According to Liem et al., the organogenesis of the eye is pointed out as an example of a developmental cascade of inductions. The eye is essentially a derivative of the ectoderm from the somatic ectoderm and neural tube, with a succession of inductions by the chordamesoderm. Chordamesoderm induces the anterior portion of the neural tube to form the precursors of the synapomorphic tripartite brain of vertebrates, and it will form a bulge called the diencephalon. Further induction by the chordamesoderm will form a protrusion: the optic vesicle. This vesicle will be subsequently invaginated by
Eye development
3863096
formation of connections between spinal neurons. Neuromere Neuromeres are morphologically or molecularly defined transient segments of the early developing brain. Rhombomeres are such segments that make up the rhombencephalon or hindbrain. More controversially, some argue that there exist early developmental segments that give rise to structures of the midbrain (mesomeres) and forebrain (prosomeres). Neuromeres are the segments of the neural tube that establish the embryonic brain during development. They can then be divided up so that each is carrying different and unique genetic traits, expressing different features in development. Neuromeres were first discovered in the beginning of the 20th century.
Neuromere
3863075
Neuromere Neuromeres are morphologically or molecularly defined transient segments of the early developing brain. Rhombomeres are such segments that make up the rhombencephalon or hindbrain. More controversially, some argue that there exist early developmental segments that give rise to structures of the midbrain (mesomeres) and forebrain (prosomeres). Neuromeres are the segments of the neural tube that establish the embryonic brain during development. They can then be divided up so that each is carrying different and unique genetic traits, expressing different features in development. Neuromeres were first discovered in the beginning of the 20th century. Although researchers have long since recognized
Neuromere
1348498
The twitches thus superimpose on one another, leading to a force greater than that of a single twitch. A tetanic contraction is caused by constant, very high frequency stimulation - the action potentials come at such a rapid rate that individual twitches are indistinguishable, and tension rises smoothly eventually reaching a plateau. Motor neurons begin to develop early in embryonic development, and motor function continues to develop well into childhood. In the neural tube cells are specified to either the rostral-caudal axis or ventral-dorsal axis. The axons of motor neurons begin to appear in the fourth week of development from
Motor neuron
2909489
the dorsal root ganglia or the trigeminal ganglia. The trigeminal ganglia are specialized nerves for the face, whereas the dorsal root ganglia are associated with the rest of the body. The axons extend into the peripheral nervous system and terminate in branches to form receptive fields. Nociceptors develop from neural-crest stem cells. The neural crest is responsible for a large part of early development in vertebrates. It is specifically responsible for development of the peripheral nervous system (PNS). The neural-crest stem cells split from the neural tube as it closes, and nociceptors grow from the dorsal part of this neural-crest
Nociceptor
17280288
neural plate. The growth of the brain and the cephalic folds push the oropharyngeal membrane forward, while the heart and the pericardial cavity move first to the cervical region and then into the chest. The curved portion of the horseshoe-shaped area expands to form the future ventricular infundibulum and the ventricular regions, as the heart tube continues to expand. The tube starts receiving venous drainage in its caudal pole and will pump blood out of the first aortic arch and into the dorsal aorta through its polar head. Initially the tube remains attached to the dorsal part of the pericardial
Heart development
4594498
plate starts when dorsal mesoderm signals ectodermal cells above it to lengthen into columnar neural plate cells. This different shape distinguishes the cells of the presumptive neural plate from other pre-epidermal cells. If the neural plate is separated by itself, it will still develop to make a thinner plate but will not form a neural tube. If the region containing presumptive epidermis and neural plate tissue is isolated, small neural folds will form. Elongation that occurs throughout the formation of the neural plate and closure of the neural tube is vital; the closing areas of the neural tube are seen
Neural plate
3863094
neural tube during development. As the neural tube begins to develop, the notochord begins to secrete a factor known as Sonic hedgehog or SHH. As a result, the floor plate then also begins to secrete SHH, and this will induce the basal plate to develop motor neurons. Meanwhile, the overlying ectoderm secretes bone morphogenetic protein (BMP). This induces the roof plate to begin to secrete BMP, which will induce the alar plate to develop sensory neurons. The alar plate and the basal plate are separated by the sulcus limitans. Additionally, the floor plate also secretes netrins. The netrins act as
Neuromere
15192202
Neurocristopathy Neurocristopathy is a diverse class of pathologies that may arise from defects in the development of tissues containing cells commonly derived from the embryonic neural crest cell lineage. The term was coined by Robert P. Bolande in 1974. After the induction of the neural crest, the newly formed neural crest cells (NCC) delaminate from their tissue of origin and migrate from the entire neural axis of the vertebrate embryo to specific locations where they will give rise to different cell derivatives. The formation of this cell population therefore requires a timely and spatially controlled interplay of inter- and intra-cellular
Neurocristopathy
6981343
Phu Quoc Ridgeback, and Thai Ridgeback, in which it is hereditary, Kerry Blue Terriers, Shih Tzus and Boxers. Dermoid sinus Dermoid sinus is a thought to be a genetic skin condition in dogs. It is also known as "pilonidal sinus". However, unlike pilonidal sinus in humans, the dermoid sinus in dogs is a neural tube defect. Dermoid sinus is sometimes also confused with dermoid cyst (a teratoma). A dermoid sinus is rare in dogs and cats. It can appear as single or multiple lumps on the dorsal midline. The sinus is caused in the embryonic stage of development. In normal
Dermoid sinus
6914694
observed in individuals with DiGeorge syndrome. TBX1 is part of the T-box family of genes which have an important role in tissue and organ formation during embryonic development and it may have a role in the regulation of differentiation of post migration neural crest cells. The neural crest forms many of the structures affected in DiGeorge syndrome, including the skull bones, mesenchyme of the face and palate, the outflow tract of the heart, and the thymus and parathyroid stroma. When there is a loss of expression of FGF18 during the development of the pharyngeal arches, neural crest cell death is
DiGeorge syndrome
10583763
become progressively smaller until they close completely (by day 26) forming the neural tube. Organogenesis is the development of the organs that begins during the third to eighth week, and continues until birth. Sometimes full development, as in the lungs, continues after birth. Different organs take part in the development of the many organ systems of the body. Haematopoietic stem cells that give rise to all the blood cells develop from the mesoderm. The development of blood formation takes place in clusters of blood cells, known as blood islands, in the yolk sac. Blood islands develop outside the embryo, on
Human embryogenesis
1669153
lie at the roof of the nasal cavity and may be mistaken for a nasal polyp. They are treated surgically. Encephalomeningoceles are classified in the same way and also contain brain tissue. Myelomeningocele (MMC), also known as meningomyelocele, is the type of spina bifida that often results in the most severe complications and affects the meninges and nerves. In individuals with myelomeningocele, the unfused portion of the spinal column allows the spinal cord to protrude through an opening. Myelomeningocele occurs in the third week of embryonic development, during neural tube pore closure. MMC is a failure of this to occur
Spina bifida