Question

Which of the following sequences of steps is CORRECT for motor axon growth?

A. Axons leave spinal cord, rearrange in plexus, divide muscle nerves, run through large nerves, synapse on individual muscle fibers.
B. Divide muscle nerves, axons leave spinal cord, run through large nerves, synapse on individual muscle fibers, rearrange in plexus.
C. Rearrange in plexus, divide muscle nerves, axons leave spinal cord, run through large nerves, synapse on individual muscle fibers.
D. Axons leave spinal cord, rearrange in plexus, run through large nerves, divide muscle nerves, synapse on individual muscle fibers.
E. None of the above.

Answer 1

The correct sequence for motor axon growth is that axons leave the spinal cord, rearrange in a plexus, run through large nerves, divide into muscle nerves, and finally synapse on individual muscle fibers.

Step-by-step explanation:

Correct motor axon growth follows a distinct pathway from the central nervous system to the muscle fibers they innervate. The correct sequence for motor axon growth is as follows: Axons leave the spinal cord, rearrange in plexus, run through large nerves, divide into muscle nerves, and finally synapse on individual muscle fibers. This sequence accounts for the origin of axons in the ventral horn of the spinal cord, their extension through the ventral nerve root into spinal nerves, the organization into nerve plexuses for the distribution of these axons to various parts of the body, and eventually their branching to connect to muscle fibers at neuromuscular junctions.