Question

Where do lower motor neurons originate?

A) brainstem
B) ventral horn of the spinal cord
C) primary somatosensory cortex
D) cerebellum
E) primary motor cortex"

Answer 1

Lower motor neurons are found in the ventral horn of the spinal cord and are responsible for the activation of skeletal muscles. They are connected to the primary motor cortex through descending tracts like the corticospinal and corticobulbar tracts.

Step-by-step explanation:

Lower motor neurons originate in the ventral horn of the spinal cord. They are crucial components of the somatic nervous system, responsible for the contraction of skeletal muscles. These neurons are large, multipolar, and possess a corona of dendrites around the cell body. Their axons extend from the ventral horn and travel through the ventral nerve root, ultimately joining with the emerging spinal nerves to reach the periphery of the body, including muscles such as those in the feet.

Descending pathways from the primary motor cortex, like the corticobulbar and corticospinal tracts, are comprised of axons from Betz cells which synapse with these lower motor neurons located in either the brain stem or the ventral horn of the spinal cord. This connection demonstrates the direct link between cortical motor commands and the activation of skeletal muscles through the lower motor neurons.