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The dorsal nerve cord is an anatomical feature found in chordate animals, mainly in the subphyla Vertebrata and Cephalochordata, as well as in some hemichordates.It is one of the five embryonic features unique to all chordates, the other four being a notochord, a post-anal tail, an endostyle, and pharyngeal slits.
The dorsal nerve cord serves as a hollow-like backbone where signals are sent throughout the body due to nervous tissue being located in this region. [2] The notochord is also toward the tail of the chordate but closer toward the middle of the body than the dorsal nerve cord and is a water-filled structure that allows the chordate to move in ...
The spinal cord develops from the posterior neural tube. As the spinal cord develops, the cells making up the wall of the neural tube proliferate and differentiate into the neurons and glia of the spinal cord. The dorsal tissues will be associated with sensory functions, and the ventral tissues will be associated with motor functions. [2]
A hollow dorsal nerve cord, also known as the neural tube, which develops into the spinal cord, the main communications trunk of the nervous system. In vertebrates, the rostral end of the neural tube enlarges into several vesicles during embryonic development, which give rise to the brain. Pharyngeal slits.
Observations of amphioxus anatomy began in the middle of the 19th century. First, the adult then the embryonic anatomy were described. [35] Alexander Kowalevsky first described the key anatomical features of the adult amphioxus (hollow dorsal nerve tube, endostyle, segmented body, postanal tail). [35]
In secondary neurulation, the neural ectoderm and some cells from the endoderm form the medullary cord. The medullary cord condenses, separates and then forms cavities. [34] These cavities then merge to form a single tube. Secondary neurulation occurs in the posterior section of most animals but it is better expressed in birds.
The dorsal rami provide motor innervation to the deep (a.k.a. intrinsic or true) muscles of the back, and sensory innervation to the skin of the posterior portion of the head, neck and back. [1] A spinal nerve splits within the intervertebral foramen to form a dorsal ramus and a ventral ramus. The dorsal ramus then turns to course posterior ...
Sectional organization of spinal cord. The spinal cord is the main pathway for information connecting the brain and peripheral nervous system. [3] [4] Much shorter than its protecting spinal column, the human spinal cord originates in the brainstem, passes through the foramen magnum, and continues through to the conus medullaris near the second lumbar vertebra before terminating in a fibrous ...