Respiratory physiology: V/Q mismatch: 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 physiology: V/Q mismatch

Sample item

Which region of an upright normal lung has the highest ventilation-perfusion ratio?

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

The answer and the reasoning

B. Apex

Both ventilation and perfusion decrease from base to apex in an upright lung, but perfusion falls more steeply. The apex therefore has a higher V/Q ratio than the base.

Option by option

  • A. Pleural space

    Pleural space does not exchange gas.

  • B. Apex (correct)

    Correct. Relative underperfusion produces high apical V/Q.

  • C. Base

    The base has lower V/Q because perfusion is relatively greater.

  • D. Hilum only

    The hilum is not a physiologic V/Q zone category.

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.

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Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is B, Apex. Both ventilation and perfusion decrease from base to apex in an upright lung, but perfusion falls more steeply.

Why is "Pleural space" not the answer?

Pleural space does not exchange gas.

Why is "Base" not the answer?

The base has lower V/Q because perfusion is relatively greater.

Why is "Hilum only" not the answer?

The hilum is not a physiologic V/Q zone category.

What concept does this question test?

It tests Respiratory physiology: V/Q mismatch in Physiology. The apex therefore has a higher V/Q ratio than the base.

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 Respiratory physiology: V/Q mismatch?

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.