Respiratory system: apneusis after pontine section: practice question

A Physiology 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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Physiology · Respiratory system: apneusis after pontine section

Sample item

In an experimental animal, the brainstem is sectioned between the upper and middle pons and both vagi are cut. What breathing pattern results?

ARegular breathing identical to normalBRapid shallow breathingCProlonged inspiratory gasps with brief expirationsDComplete and permanent apnoea

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

The answer and the reasoning

C. Prolonged inspiratory gasps with brief expirations

The pneumotaxic centre in the upper pons and vagal stretch afferents both help terminate inspiration. When both inputs are removed, the apneustic centre drives sustained inspiration, producing apneusis. The medullary groups still generate a basic rhythm, so breathing does not stop.

Option by option

A. Regular breathing identical to normal
The pattern is clearly abnormal because the off-switch for inspiration is lost.
B. Rapid shallow breathing
Rapid shallow breathing follows vagal stimulation, not its removal.
C. Prolonged inspiratory gasps with brief expirations (correct)
Correct. Without the pneumotaxic and vagal off-switches, inspiration is prolonged.
D. Complete and permanent apnoea
The medullary rhythm generator survives, so breathing continues.

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 Physiology question

What is the answer to this Physiology question?

The best answer is C, Prolonged inspiratory gasps with brief expirations. The pneumotaxic centre in the upper pons and vagal stretch afferents both help terminate inspiration.

Why is "Regular breathing identical to normal" not the answer?

The pattern is clearly abnormal because the off-switch for inspiration is lost.

Why is "Rapid shallow breathing" not the answer?

Rapid shallow breathing follows vagal stimulation, not its removal.

Why is "Complete and permanent apnoea" not the answer?

The medullary rhythm generator survives, so breathing continues.

What concept does this question test?

It tests Respiratory system: apneusis after pontine section in Physiology. When both inputs are removed, the apneustic centre drives sustained inspiration, producing apneusis. The medullary groups still generate a basic rhythm, so breathing does not stop.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Respiratory system: apneusis after pontine section?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.