Inflammation and repair: Wallerian degeneration: practice question

A Pathology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pathology · Inflammation and repair: Wallerian degeneration

Sample item

A peripheral nerve is completely transected in an accident. Which sequence of events occurs in the segment distal to the cut?

AAxonal and myelin breakdown with Schwann cell proliferationBImmediate regrowth of axons along intact myelinCNeuronal cell body death with sparing of the axonDSegmental demyelination with preserved axons

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Axonal and myelin breakdown with Schwann cell proliferation

After transection the distal axon and myelin degenerate (Wallerian degeneration), macrophages clear debris and Schwann cells proliferate to form guiding bands. Regeneration proceeds from the proximal stump at roughly 1 mm per day if the ends are aligned. Neurons are permanent cells, but their axons can regenerate.

Option by option

A. Axonal and myelin breakdown with Schwann cell proliferation (correct)
Correct. The distal axon and myelin break down while Schwann cells prepare a path for regrowth.
B. Immediate regrowth of axons along intact myelin
Axons regrow from the proximal stump and not instantly from the distal segment.
C. Neuronal cell body death with sparing of the axon
The cell body usually survives and reacts with chromatolysis; the distal axon is lost.
D. Segmental demyelination with preserved axons
Segmental demyelination with preserved axons characterises some neuropathies, not transection.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is A, Axonal and myelin breakdown with Schwann cell proliferation. After transection the distal axon and myelin degenerate (Wallerian degeneration), macrophages clear debris and Schwann cells proliferate to form guiding bands.

Why is "Immediate regrowth of axons along intact myelin" not the answer?

Axons regrow from the proximal stump and not instantly from the distal segment.

Why is "Neuronal cell body death with sparing of the axon" not the answer?

The cell body usually survives and reacts with chromatolysis; the distal axon is lost.

Why is "Segmental demyelination with preserved axons" not the answer?

Segmental demyelination with preserved axons characterises some neuropathies, not transection.

What concept does this question test?

It tests Inflammation and repair: Wallerian degeneration in Pathology. Regeneration proceeds from the proximal stump at roughly 1 mm per day if the ends are aligned. Neurons are permanent cells, but their axons can regenerate.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Inflammation and repair: Wallerian degeneration?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.