Respiratory system: non-respiratory functions of the lung: 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.

Try it

Physiology · Respiratory system: non-respiratory functions of the lung

Sample item

A 55-year-old hypertensive woman started on ramipril develops a persistent dry cough. Which non-respiratory pulmonary function explains this adverse effect?

AReduced degradation of bradykinin by angiotensin-converting enzyme on pulmonary capillary endotheliumBReduced inactivation of histamine by the pulmonary endotheliumCLoss of prostaglandin E2 inactivation by pulmonary macrophagesDReduced synthesis of surfactant by type II pneumocytes

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

The answer and the reasoning

A. Reduced degradation of bradykinin by angiotensin-converting enzyme on pulmonary capillary endothelium

Pulmonary capillary endothelium contains abundant ACE, which converts angiotensin I to II and also degrades bradykinin. ACE inhibitors raise bradykinin and substance P in the airway, producing the characteristic dry cough, and rarely angioedema. The lung inactivates bradykinin, serotonin, noradrenaline and some prostaglandins, but not histamine or dopamine.

Option by option

A. Reduced degradation of bradykinin by angiotensin-converting enzyme on pulmonary capillary endothelium (correct)
Correct. Accumulated bradykinin sensitises airway sensory nerves and causes cough.
B. Reduced inactivation of histamine by the pulmonary endothelium
The lung does not significantly inactivate histamine.
C. Loss of prostaglandin E2 inactivation by pulmonary macrophages
Prostaglandin inactivation occurs largely in the pulmonary endothelium and is not the cause of ACE inhibitor cough.
D. Reduced synthesis of surfactant by type II pneumocytes
Surfactant synthesis is not affected by ACE inhibitors.

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 A, Reduced degradation of bradykinin by angiotensin-converting enzyme on pulmonary capillary endothelium. Pulmonary capillary endothelium contains abundant ACE, which converts angiotensin I to II and also degrades bradykinin.

Why is "Reduced inactivation of histamine by the pulmonary endothelium" not the answer?

The lung does not significantly inactivate histamine.

Why is "Loss of prostaglandin E2 inactivation by pulmonary macrophages" not the answer?

Prostaglandin inactivation occurs largely in the pulmonary endothelium and is not the cause of ACE inhibitor cough.

Why is "Reduced synthesis of surfactant by type II pneumocytes" not the answer?

Surfactant synthesis is not affected by ACE inhibitors.

What concept does this question test?

It tests Respiratory system: non-respiratory functions of the lung in Physiology. ACE inhibitors raise bradykinin and substance P in the airway, producing the characteristic dry cough, and rarely angioedema. The lung inactivates bradykinin, serotonin, noradrenaline and some prostaglandins, but not histamine or dopamine.

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: non-respiratory functions of the lung?

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.