Respiratory system: emphysema mechanics: 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: emphysema mechanics

Sample item

A 62-year-old smoker has a barrel chest, prolonged expiration and a very low FEV1/FVC. Why do his small airways collapse during forced expiration?

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

The answer and the reasoning

D. Loss of elastic recoil reduces radial traction on the airways

Destruction of alveolar walls removes the radial traction that holds small airways open, so they collapse early in expiration and air trapping results. Compliance and total lung capacity are increased.

Option by option

  • A. Fibrosis of the alveolar septa

    Fibrosis stiffens the lung and is the pattern of restrictive disease.

  • B. Excessive surfactant raising surface tension

    Surfactant lowers surface tension, and excess would not collapse airways.

  • C. Hypertrophy of bronchial smooth muscle

    Smooth muscle hypertrophy is the feature of asthma, not emphysema.

  • D. Loss of elastic recoil reduces radial traction on the airways (correct)

    Correct. Loss of elastic tissue removes radial traction and airways collapse.

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 D, Loss of elastic recoil reduces radial traction on the airways. Destruction of alveolar walls removes the radial traction that holds small airways open, so they collapse early in expiration and air trapping results.

Why is "Fibrosis of the alveolar septa" not the answer?

Fibrosis stiffens the lung and is the pattern of restrictive disease.

Why is "Excessive surfactant raising surface tension" not the answer?

Surfactant lowers surface tension, and excess would not collapse airways.

Why is "Hypertrophy of bronchial smooth muscle" not the answer?

Smooth muscle hypertrophy is the feature of asthma, not emphysema.

What concept does this question test?

It tests Respiratory system: emphysema mechanics in Physiology. Compliance and total lung capacity are increased.

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 system: emphysema mechanics?

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.