General anatomy and histology: Wallerian degeneration: practice question

A Anatomy 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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Anatomy · General anatomy and histology: Wallerian degeneration

Sample item

A transected peripheral nerve is repaired end to end. In the distal stump, which cells proliferate and line up in columns that guide the regrowing axon sprouts?

AEndoneurial mast cells depositing collagenBSatellite cells of the dorsal root ganglionCSchwann cells forming the bands of BungnerDPerineurial cells forming a new fascicular sheath

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

The answer and the reasoning

C. Schwann cells forming the bands of Bungner

After axonal transection the distal axon and myelin break down (Wallerian degeneration) and macrophages clear the debris. Schwann cells divide and form cellular columns, the bands of Bungner, which guide regenerating axons to their targets. Regeneration is far poorer in the CNS, where oligodendrocytes do not provide this support.

Option by option

A. Endoneurial mast cells depositing collagen
Mast cells may add to scarring but give no guidance channel for axons.
B. Satellite cells of the dorsal root ganglion
Satellite cells lie around ganglion cell bodies and do not line the distal nerve stump.
C. Schwann cells forming the bands of Bungner (correct)
Correct. Distal Schwann cells proliferate into columns that act as a guidance tube for sprouting axons.
D. Perineurial cells forming a new fascicular sheath
Perineurial cells form the blood-nerve barrier and do not guide axon sprouts.

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 Anatomy question

What is the answer to this Anatomy question?

The best answer is C, Schwann cells forming the bands of Bungner. After axonal transection the distal axon and myelin break down (Wallerian degeneration) and macrophages clear the debris.

Why is "Endoneurial mast cells depositing collagen" not the answer?

Mast cells may add to scarring but give no guidance channel for axons.

Why is "Satellite cells of the dorsal root ganglion" not the answer?

Satellite cells lie around ganglion cell bodies and do not line the distal nerve stump.

Why is "Perineurial cells forming a new fascicular sheath" not the answer?

Perineurial cells form the blood-nerve barrier and do not guide axon sprouts.

What concept does this question test?

It tests General anatomy and histology: Wallerian degeneration in Anatomy. Schwann cells divide and form cellular columns, the bands of Bungner, which guide regenerating axons to their targets. Regeneration is far poorer in the CNS, where oligodendrocytes do not provide this support.

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 General anatomy and histology: Wallerian degeneration?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy 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.