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The notochord is a long, rod-like midline structure that develops dorsal to the gut tube and ventral to the neural tube. The notochord is composed primarily of a glycoproteins core that is encased in a sheath of collagen fibers. This is wound into two opposing helices.
The notochord plays an integral role in the development of the neural tube. Prior to neurulation, during the migration of epiblastic endoderm cells towards the hypoblastic endoderm, the notochordal process opens into an arch termed the notochordal plate and attaches overlying neuroepithelium of the neural plate.
The neural tube develops in two ways: primary neurulation and secondary neurulation. Primary neurulation divides the ectoderm into three cell types: The internally located neural tube; The externally located epidermis; The neural crest cells, which develop in the region between the neural tube and epidermis but then migrate to new locations
[5] [6] The neural plate is the source of the majority of neurons and glial cells of the CNS. The neural groove forms along the long axis of the neural plate, and the neural plate folds to give rise to the neural tube. [7] This process is known as neurulation. [8] When the tube is closed at both ends it is filled with embryonic cerebrospinal ...
The neural tube itself is the initial groundwork of the vertebrate CNS, and the floor plate is a specialized structure, located at the ventral midpoint of the neural tube. Evidence supporting the notochord as the signaling center comes from studies in which a second notochord is implanted near a neural tube in vivo, leading to the formation of ...
The process by which neural tube is performed from the ectoderm is called neurulation. The evolutionary explanation to this adaptation from a solid cord to a hollow tube is unknown. In vertebrates, the dorsal nerve cord (and the subsequent neural tube) gives rise to the brain (via vesicular enlargements at the rostral end) and spinal cord ...
The communication between the neural plate and the notochord is important for the future induction and formation of the neural tube. Closure of the neural tube is completed when the neural folds are brought together, adhering to each other. While the cells that remain as the neural tube form the brain and spinal cord, the other cells that were ...
Neural differentiation occurs within the spinal cord portion of the tube. [13] As the neural tube begins to develop, the notochord begins to secrete a factor known as Sonic hedgehog (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 the ...