Respiratory physiology: compliance: 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: compliance

Sample item

Pulmonary surfactant increases lung compliance chiefly by doing what?

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

The answer and the reasoning

C. Lowering alveolar surface tension

Surfactant reduces surface tension at the air-liquid interface, particularly in small alveoli, reducing work of breathing and preventing collapse at low volume.

Option by option

  • A. Increasing elastic recoil of collagen

    Greater collagen recoil would reduce compliance.

  • B. Increasing airway smooth-muscle tone

    Bronchoconstriction increases airway resistance.

  • C. Lowering alveolar surface tension (correct)

    Correct. Surface-tension reduction makes alveoli easier to inflate.

  • D. Raising alveolar fluid volume

    Alveolar fluid impairs gas exchange rather than increasing compliance.

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 C, Lowering alveolar surface tension. Surfactant reduces surface tension at the air-liquid interface, particularly in small alveoli, reducing work of breathing and preventing collapse at low volume.

Why is "Increasing elastic recoil of collagen" not the answer?

Greater collagen recoil would reduce compliance.

Why is "Increasing airway smooth-muscle tone" not the answer?

Bronchoconstriction increases airway resistance.

Why is "Raising alveolar fluid volume" not the answer?

Alveolar fluid impairs gas exchange rather than increasing compliance.

What concept does this question test?

It tests Respiratory physiology: compliance in Physiology. The correct option holds because: Correct. Surface-tension reduction makes alveoli easier to inflate.

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: compliance?

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.