Wallerian degeneration is best described as what process?

• A. Degeneration of the distal portion of the axon and its myelin sheath.
• B. Degeneration of neuronal cell bodies in the CNS.
• C. Demyelination of striated muscle fibers.
• D. Regeneration of axons after injury.

Answer: (A)

When an axon is injured, the part farthest from the cell body cannot be maintained and undergoes breakdown. This is Wallerian degeneration: the distal portion of the axon and its myelin sheath degenerate and are cleared by supportive glial and immune cells. In the peripheral nervous system, Schwann cells help set up a path that can guide potential regrowth from the proximal stump. This process specifically describes distal axon and myelin destruction, not degeneration of the neuron’s cell body, not demyelination of muscle fibers, and not regeneration.