GENERAL HISTOLOGY

Detailed explanation-1: -In the spinal cord, this pathway travels in the dorsal column, and in the brainstem, it is transmitted through the medial lemniscus hence the name dorsal column-medial lemniscus pathway. Phylogenetically, this is a relatively new pathway and serves as a highly localizable and discriminative sensation.

Detailed explanation-2: -The white matter of the spinal cord is subdivided into dorsal (or posterior), lateral, and ventral (or anterior) columns, each of which contains axon tracts related to specific functions. The dorsal columns carry ascending sensory information from somatic mechanoreceptors (Figure 1.11B).

Detailed explanation-3: -The dorsal root is sensory and the ventral root motor; the first cervical nerve may lack the dorsal root. Oval swellings, the spinal ganglia, characterize the dorsal roots. They are formed of nerve cells that give rise to the sensory nerve fibres.

Detailed explanation-4: -Sensory neurons have their cell bodies in the spinal (dorsal root) ganglion. Their axons travel through the dorsal root into the gray matter of the cord.

Detailed explanation-5: -Sensory spinal nerves enter the spinal cord on the back (dorsal) side, whereas motor spinal nerves exit the spinal cord on the front (ventral) side.