The neural groove is a shallow median groove of the

neural plate In embryology, the neural plate is a key Development of the human body, developmental structure that serves as the basis for the nervous system. Cranial to the primitive node of the embryonic primitive streak, Ectoderm, ectodermal tissue thickens ...

between the

neural folds 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 tis ...

of an

embryo An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sp ...

. The neural plate is a thick sheet of

ectoderm The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from the o ...

surrounded on either side by the neural folds, two longitudinal ridges in front of the primitive streak of the developing embryo.. 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 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, ...

or canal, the ectodermal wall of which forms the rudiment of the

nervous system In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. Th ...

. After the coalescence of the neural folds over the anterior end of the primitive streak, the blastopore no longer opens on the surface but into the closed canal of the neural tube, and thus a transitory communication, the neurenteric canal, is established between the neural tube and the primitive digestive tube. The coalescence of the neural folds occurs first in the region of the hind-brain, and from there extends forward and backward; toward the end of the third week the front opening (anterior neuropore) of the tube finally closes at the anterior end of the future brain, and forms a recess which is in contact, for a time, with the overlying ectoderm; the hinder part of the neural groove presents for a time a rhomboidal shape, and to this expanded portion the term sinus rhomboidalis has been applied. Before the neural groove is closed a ridge of ectodermal cells appears along the prominent margin of each neural fold; this is termed the neural crest or

ganglion A ganglion (: ganglia) is a group of neuron cell bodies in the peripheral nervous system. In the somatic nervous system, this includes dorsal root ganglia and trigeminal ganglia among a few others. In the autonomic nervous system, there are ...

ridge, and from it, the spinal and cranial nerve ganglia and the ganglia of the sympathetic nervous system are developed. By the upward growth of the

mesoderm The mesoderm is the middle layer of the three germ layers that develops during gastrulation in the very early development of the embryo of most animals. The outer layer is the ectoderm, and the inner layer is the endoderm.Langman's Medical ...

the neural tube is ultimately separated from the overlying ectoderm. The cephalic end of the neural groove exhibits several dilatations, which, when the tube is closed, assume the form of three vesicles; these constitute the three primary cerebral vesicles and correspond respectively to the future fore-brain (prosencephalon), midbrain (mesencephalon), and hind-brain (rhombencephalon). The walls of the vesicles are developed into the nervous tissue and neuroglia of the brain, and their cavities are modified to form their ventricles. The remainder of the tube forms the medulla spinalis or spinal cord; from its ectodermal wall, the nervous and neuroglial elements of the medulla spinalis are developed while the cavity persists as the central canal.

References

Additional images

2912 Neurulation-02.jpg,

Embryogenesis in vertebrates.jpg,

Embryogenesis An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male ...

and ontogenesis in vertebrates Gray31.png, Model of human embryo 1.3 mm. long.

External links

* *
Diagram at embryology.med.unsw.edu.au
{{Authority control Embryology of nervous system

See also

References

Additional images

External links