Which statement accurately describes Wallerian degeneration?

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Multiple Choice

Which statement accurately describes Wallerian degeneration?

Wallerian degeneration is the process by which the part of an axon distal to the injury breaks down after the axon has been disrupted. This degeneration happens downstream from the lesion because that distal segment is severed from the neuron's cell body and cannot be maintained. If the axon remains intact—as in neurapraxia—there is a conduction block but no Wallerian degeneration, since the distal segment is still connected to the cell body. Conversely, when the axon is disrupted as in axonotmesis or neurotmesis, the distal portion degenerates, so the degeneration clearly occurs distal to the injury, not proximal. Therefore, the statement that it occurs distal to the injury only when the axon is disrupted best describes Wallerian degeneration.

Wallerian degeneration is the process by which the part of an axon distal to the injury breaks down after the axon has been disrupted. This degeneration happens downstream from the lesion because that distal segment is severed from the neuron's cell body and cannot be maintained. If the axon remains intact—as in neurapraxia—there is a conduction block but no Wallerian degeneration, since the distal segment is still connected to the cell body. Conversely, when the axon is disrupted as in axonotmesis or neurotmesis, the distal portion degenerates, so the degeneration clearly occurs distal to the injury, not proximal. Therefore, the statement that it occurs distal to the injury only when the axon is disrupted best describes Wallerian degeneration.

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