Neural Tube - Embryonic Development & Stem Cells

Neural Tube Spina Bifida Neural Tube Defect Curly Tail Spinal Neurulation. Copp AJ (1985) Relationship between timing of posterior neuropore closure and development of spinal neural tube defects in mutant (curly tail) and normal mouse embryos in culture.The neural tube develops into the brain, brainstem, spinal cord, and preganglionic sympathetic By week 10, the basal plate (ventral) of the neural tube becomes motor neurons of the cranial nerve and Figure 1: Early Embryonic Development of Nervous System. Courtesy of Nancy Aguilar-Roca......that becomes the embryo and an outer layer termed the trophoblasts that forms the embryonic part of As the neural tube fuses cranially, closing off the anterior neuropore, a mesencephalic flexure Simultaneously, the eye continues its development as neural crest mesoectodermal cells at the...Neurulation is the process of forming the neural tube, which will become the brain and spinal cord. The open parts of the neural tube are named anterior and posterior neuropores, after The main stages of embryonic development have been previously categorized into two stages: embryonic...Embryology - is a study of formation, embryonic structure, early growth and development of living organisms. • Identified the blastoderm surrounding the embryo of chick • Discussed the role of amniotic fluid • Found islets of blood cells before heart development.

Embryology and Development Exam Review & Practice Questions

This Tube Will Later Develop Into All Of The Following Except A. The Hindbrain. Transcribed Image Text from this Question. 1. Early in the embryonic development of a vertebrate, the neural tube forms.Neurulation is the process of forming the neural tube, which will become the brain and spinal cord. In humans, it begins in the 3rd week after fertilization and requires that the top layers of the embryonic germ disc elevate as folds and fuse in the midline. The phenomenon is complex, involves numerous...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...It is a structure that is formed from the process of neurulation where it transforms the neural plate to a neural tube.And the end result of a neural tube is the brain and the spinal cord.

Head and Neck Embryology: Embryologic Development of Skeletal...

This article describes the development and embryology of the CNS, specifically of the.brain and the The nervous system develops from a section of the ectoderm called the neural plate, which The caudal part of the neural tube (i.e. the neural tube after the fourth pair of somites) becomes...The embryonic neural tube is composed by a pseudostratified layer of neuroepithelial cells with a clear apico-basal polarity. to the characteristic interkinetic nuclear movement (INM) [9]. This particular organization of the neural tube is important for the coordinated production of neurons and glia.Embryonic development, neural tube defects, development of the heart...The neural tube resembles a channel that is open at both ends. The end of the head is called the anterior neuropore. Small perforations also form in the cranial part of the septum. They join together to create the ostium...This lecture covers the period of Embryonic development, in Humans from week 3 to week 8 (GA week 5-10) and is divided into 23 Carnegie stages of embryonic development. There will also be a brief introduction to fetal development.(The neural tube is the primitive structure from which develops the central nervous system.) Females are more likely to be affected than males. Cross section of the embryonic disk, showing formation of the neural tube in prenatal development. Encyclopædia Britannica, Inc.

Jump to navigation Jump to look Neural tubeTransverse segment of half of a chick embryo of forty-five hours' incubation. The dorsal (back) surface of the embryo is towards the top of this web page, while the ventral (entrance) surface is towards the backside. (Neural tube is in green.)Chick embryo of thirty-three hours' incubation, considered from the dorsal side (30x magnification).DetailsCarnegie stage10PrecursorNeural grooveGives upward push toCentral fearful machine (brain and spinal wire)IdentifiersLatintubus neuralis, tuba neuralisMeSHD054259TEtube_by_E5.14.1.0.0.0.1 E5.14.1.0.0.0.1 Anatomical terminology

In the creating chordate (including vertebrates), the neural tube is the embryonic precursor to the central apprehensive system, which is made up of the brain and spinal twine. The neural groove step by step deepens as the neural folds become increased, and in the long run the folds meet and coalesce in the center line and convert the groove into the closed neural tube. In people, neural tube closure in most cases occurs by way of the fourth week of being pregnant (twenty eighth day after conception). The ectodermal wall of the tube forms the rudiment of the apprehensive system. The centre of the tube is the neural canal.

Stages of neural tube formation.

Development

Main article: Neurulation

The neural tube develops in two tactics: number one neurulation and secondary neurulation.

Primary neurulation divides the ectoderm into 3 cellular types:

The internally positioned neural tube The externally located epidermis The neural crest cells, which expand in the region between the neural tube and dermis but then migrate to new locationsPrimary neurulation begins after the neural plate forms. The edges of the neural plate begin to thicken and lift upward, forming the neural folds. The heart of the neural plate stays grounded, permitting a U-shaped neural groove to shape. This neural groove units the boundary between the appropriate and left sides of the embryo. The neural folds pinch in towards the midline of the embryo and fuse in combination to form the neural tube.[1] In secondary neurulation, the cells of the neural plate shape a cord-like structure that migrates inside the embryo and hollows to shape the tube.

Each organism makes use of number one and secondary neurulation to various levels.

Neurulation in fish proceeds most effective by means of the secondary shape. In avian species the posterior areas of the tube expand the use of secondary neurulation and the anterior areas develop through primary neurulation. In mammals, secondary neurulation starts round the thirty fifth somite.

Mammalian neural tubes shut in the head in the opposite order that they close in the trunk.

In the head:Neural crest cells migrate Neural tube closes Overlying ectoderm closesIn the trunk:Overlying ectoderm closes Neural tube closes Neural crest cells migrate

Structure

Four neural tube subdivisions each ultimately turn out to be distinct regions of the central frightened system by the division of neuroepithelial cells: the forebrain (prosencephalon), the midbrain (mesencephalon), the hindbrain (rhombencephalon) and the spinal wire.

The prosencephalon further goes on to turn out to be the telencephalon (cerebrum) and the diencephalon (the optic vesicles and hypothalamus). The mesencephalon remains as the midbrain. The rhombencephalon develops into the metencephalon (the pons and cerebellum) and the myelencephalon (the medulla oblongata).

For a short while, the neural tube is open both cranially and caudally. These openings, known as neuropores, close during the fourth week in people. Improper closure of the neuropores can lead to neural tube defects such as anencephaly or spina bifida.

The dorsal part of the neural tube comprises the alar plate, which is related basically with sensation. The ventral part of the neural tube incorporates the basal plate, which is primarily associated with motor (i.e., muscle) keep watch over.

Dorsal-ventral patterning

The neural tube patterns along the dorsal-ventral axis to establish explained compartments of neural progenitor cells that result in distinct classes of neurons.[2] According to the French flag fashion of morphogenesis, this patterning happens early in construction and results from the activity of a number of secreted signaling molecules. Sonic hedgehog (Shh) is a key participant in patterning the ventral axis, whilst bone morphogenic proteins (BMPs) and Wnt members of the family play an important role in patterning the dorsal axis.[3] Other factors proven to offer positional knowledge to the neural progenitor cells include fibroblast enlargement components (FGFs) and retinoic acid. Retinoic acid is needed ventrally along with Shh to induce Pax6 and Olig2 right through differentiation of motor neurons.[4]

Three main ventral mobile types are established all through early neural tube development: the ground plate cells, which form at the ventral midline right through the neural fold degree; as well as the more dorsally positioned motor neurons and interneurons.[2] These cellular sorts are laid out in the secretion of the Shh from the notochord (positioned ventrally to the neural tube), and later from the flooring plate cells.[5] Shh acts as a morphogen, meaning that it acts in a concentration-dependent way to specify cellular sorts as it moves further from its source.[6]

The following is a proposed mechanism for how Shh patterns the ventral neural tube: A gradient of Shh that controls the expression of a bunch of homeodomain (HD) and basic Helix-Loop-Helix (bHLH) transcription elements is created. These transcription elements are grouped into two protein classes in keeping with how Shh impacts them. Class I is inhibited by way of Shh, while Class II is activated by Shh. These two categories of proteins then cross-regulate each other to create more-defined boundaries of expression. The different combinations of expression of those transcription components alongside the dorsal-ventral axis of the neural tube are answerable for growing the identity of the neuronal progenitor cells.[3] Five molecularly distinct groups of ventral neurons form from those neuronal progenitor cells in vitro. Also, the position at which these neuronal groups are generated in vivo can be predicted through the concentration of Shh required for his or her induction in vitro.[7] Studies have shown that neural progenitors can evoke other responses in line with the period of publicity to Shh, with a longer exposure time leading to extra ventral mobile varieties.[8][9]

At the dorsal finish of the neural tube, BMPs are answerable for neuronal patterning. BMP is to start with secreted from the overlying ectoderm. A secondary signaling center is then established in the roof plate, the dorsal most construction of the neural tube.[1] BMP from the dorsal finish of the neural tube turns out to behave in the similar concentration-dependent means as Shh in the ventral end.[10] This was proven using zebrafish mutants that had varying quantities of BMP signaling process. Researchers seen adjustments in dorsal-ventral patterning, for example zebrafish poor in sure BMPs confirmed a loss of dorsal sensory neurons and an expansion of interneurons.[11]

Shh secreted from the floor plate creates a gradient along the ventral neural tube. Shh functions in a concentration-dependent method to specify ventral neuronal fates. V0-V3 constitute four different categories of ventral interneurons, and MN indicates motor neurons.

References

This article contains textual content in the public domain from page 50 of the 20th version of Gray's Anatomy (1918)

^ a b Gilbert, Scott F. Developmental Biology Eighth Edition. Sunderland, Massachusetts: Sinauer Associates, Inc., 2006. ^ a b .mw-parser-output cite.citationfont-style:inherit.mw-parser-output .citation qquotes:"\"""\"""'""'".mw-parser-output .id-lock-free a,.mw-parser-output .quotation .cs1-lock-free abackground:linear-gradient(clear,transparent),url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat.mw-parser-output .id-lock-limited a,.mw-parser-output .id-lock-registration a,.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration abackground:linear-gradient(clear,transparent),url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")correct 0.1em center/9px no-repeat.mw-parser-output .id-lock-subscription a,.mw-parser-output .quotation .cs1-lock-subscription abackground:linear-gradient(transparent,transparent),url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")correct 0.1em center/9px no-repeat.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registrationcolour:#555.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration spanborder-bottom:1px dotted;cursor:help.mw-parser-output .cs1-ws-icon abackground:linear-gradient(transparent,transparent),url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em middle/12px no-repeat.mw-parser-output code.cs1-codecolor:inherit;background:inherit;border:none;padding:inherit.mw-parser-output .cs1-hidden-errordisplay:none;font-size:100%.mw-parser-output .cs1-visible-errorfont-size:100%.mw-parser-output .cs1-maintdisplay:none;color:#33aa33;margin-left:0.3em.mw-parser-output .cs1-formatfont-size:95%.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-leftpadding-left:0.2em.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-rightpadding-right:0.2em.mw-parser-output .quotation .mw-selflinkfont-weight:inheritJessell TM (2000). "Neuronal specification in the spinal cord: inductive signals and transcriptional codes". Nat Rev Genet. 1 (1): 20–9. doi:10.1038/35049541. PMID 11262869. S2CID 205012382. ^ a b Ulloa F, Marti E (2010). "Wnt won the war: Antagonistic role of Wnt over Shh controls dorso-ventral patterning of the vertebrate neural tube". Developmental Dynamics. 239 (1): 69–76. doi:10.1002/dvdy.22058. PMID 19681160. S2CID 205766310. ^ Duester G (2008). "Retinoic acid synthesis and signaling during early organogenesis". Cell. 134 (6): 921–931. doi:10.1016/j.cellular.2008.09.002. PMC 2632951. PMID 18805086. ^ Patten I, Placzek M (2000). "The role of Sonic hedgehog in neural tube patterning". Cell Mol Life Sci. 57 (12): 1695–708. doi:10.1007/pl00000652. PMID 11130176. S2CID 20950575. ^ Dessaud E, McMahon AP, Briscoe J (2008). "Pattern formation in the vertebrate neural tube: a sonic hedgehog morphogen-regulated transcriptional network". Development. 135 (15): 2489–2503. doi:10.1242/dev.009324. PMID 18621990. ^ Ericson J, Briscoe J, Rashbass P, van Heyningen V, Jessell TM (1997). "Graded Sonic hedgehog signaling and the specification of cell fate in the ventral neural tube". Cold Spring Harb Symp Quant Biol. 62: 451–466. doi:10.1101/SQB.1997.062.01.053. PMID 9598380. ^ Stamataki D, Ulloa F, Tsoni SV, Mynett A, Briscoe J (2005). "A gradient of Gli activity mediates graded Sonic hedgehog signaling in the neural tube". Genes Dev. 19 (5): 626–641. doi:10.1101/gad.325905. PMC 551582. PMID 15741323. ^ Dessaud E, Yang LL, Hill K, et al. (November 2007). "Interpretation of the sonic hedgehog morphogen gradient by a temporal adaptation mechanism" (PDF). Nature. 450 (7170): 717–20. doi:10.1038/nature06347. hdl:2027.42/62511. PMID 18046410. S2CID 4419025. ^ Wilson L, Maden M (2005). "The mechanisms of dorsoventral patterning in the vertebrate neural tube". Developmental Biology. 282 (1): 1–13. doi:10.1016/j.ydbio.2005.02.027. PMID 15936325. ^ Nguyen VH, Trout J, Connors SA, Andermann P, Weinberg E, Mullins MC (2000). "Dorsal and intermediate neuronal cell types of the spinal cord are established by a BMP signaling pathway". Development. 127 (6): 1209–1220. PMID 10683174.

External links

Swiss embryology (from UL, UB, and UF) iperiodembry/carnegie03 Embryology at UNSW Notes/week3_5 Diagram at embryology.med.unsw.edu.au Diagram at brainviews.comvteDevelopment of the anxious systemNeurogenesisGeneral Neural development Neurulation Neurula Notochord Neuroectoderm Neural plate Neural fold Neural groove Neuropoiesis Adult neurogenesisNeural crest Cranial neural crest Cardiac neural crest complex Truncal neural crestNeural tube Rostral neuropore Neuromere / Rhombomere Cephalic flexure Cervical flexure Pontine flexure Alar plate Basal plate Glioblast Neuroblast Germinal matrixEye Neural tube Optic vesicle Optic stalk Optic cup Surface ectoderm Lens placodeEar Otic placode Otic pit Otic vesicle Authority keep watch over GND: 4202155-8 LCCN: sh85091098 MA: 2780594696 TE: E5.14.1.0.0.0.1 Retrieved from "https://en.wikipedia.org/w/index.php?title=Neural_tube&oldid=997444978"