A first-order neuron of the posterior column-medial lemniscus pathway from the arm joins other axons to form the posterior column in the spinal column.It would synapse with second-order neuron cell bodies located in the _____.
A)gracile fasciculus
B)cuneate fasciculus
C)dorsal gray horn
D)cuneate nucleus
E)gracile nucleus

Question

Quizplus · Accepted Answer

The second-order neuron cell bodies for the arm fibers of the posterior column-medial lemniscus pathway are located in the cuneate nucleus, which is specific to the upper extremity. The gracile nucleus is responsible for lower extremity sensations. The dorsal gray horn contains interneurons and motor neurons for spinal reflexes, and the gracile and cuneate fasciculi are tracts within the posterior columns. Therefore, the best choice is D, the cuneate nucleus.

A First-Order Neuron of the Posterior Column-Medial Lemniscus Pathway from the Arm