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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 .
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.
The name dorsal-column medial lemniscus comes from the two structures that carry the sensory information: the dorsal columns of the spinal cord, and the medial lemniscus in the brainstem. There are three groupings of neurons that are involved in the pathway: first-order neurons, second-order neurons, and third-order neurons.
It occupies the medial part of the base of the posterior grey column and appears on the transverse section as a well-defined oval area. It begins caudally at the level of the second or third lumbar nerve, and reaches its maximum size opposite the twelfth thoracic nerve. Above the level of the eight thoracic nerve its size diminishes, and the ...
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]
The posterolateral tract contains centrally projecting axons from dorsal root ganglion cells carrying peripheral pain and temperature information (location, intensity and quality). These axons enter the spinal column and penetrate the grey matter of the dorsal horn, where they synapse on second-order neurons in either the substantia gelatinosa ...
Spinal nerve forming from grey column. The posterior grey column, also known as the posterior (or dorsal) horn of spinal cord, is subdivided into six layers known as Rexed laminae, based on the type of sensory information sent to each section. [8] Marginal nucleus of spinal cord (lamina I) Substantia gelatinosa of Rolando (lamina II)
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 ...