Question

13 what is a reason that the axons in the cns and pns differ in their ability to regenerate after injury? multiple choice axons of the pns lack schwann cells. axons of the cns lack a neurilemma. axons of the cns lack myelin. axons of the pns lack an endoneurium.

Explanation:

The neurilemma (also known as the Schwann cell membrane) is crucial for axon regeneration. In the PNS (peripheral nervous system), Schwann cells form the neurilemma. When an axon in the PNS is damaged, the neurilemma remains intact and can guide the regenerating axon. In the CNS (central nervous system), oligodendrocytes myelinate axons, and there is no equivalent of the neurilemma. CNS axons lack a neurilemma, which is why their regenerative ability is different from PNS axons. Axons of the PNS have Schwann cells (so the first option is wrong), CNS axons have myelin (formed by oligodendrocytes, so the third option is wrong), and PNS axons have an endoneurium (a connective - tissue layer around individual axons, so the fourth option is wrong).

Answer:

Axons of the CNS lack a neurilemma.