Question

chapters 10 and 11 nervous syst
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 cns lack myelin.
axons of the cns lack a neurilemma.
axons of the pns lack an endoneurium.
axons of the pns lack schwann cells.

Explanation:

1. Recall the difference in axon regeneration between CNS (Central Nervous System) and PNS (Peripheral Nervous System).
2. The neurilemma (outermost layer of Schwann cells in PNS) plays a role in regeneration. CNS axons lack a neurilemma, which limits their ability to regenerate.

• Option A: CNS axons can have myelin (from oligodendrocytes), so this is incorrect.
• Option B: PNS axons have endoneurium and Schwann cells (with neurilemma) that support regeneration, so this is incorrect.
• Option D: PNS axons have Schwann cells, so this is incorrect.

Answer:

C. Axons of the CNS lack a neurilemma.