Renal physiology: ADH: 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 · Renal physiology: ADH

Sample item

Antidiuretic hormone increases water permeability of collecting ducts by inserting which channel into principal-cell apical membranes?

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

The answer and the reasoning

D. Aquaporin-2

ADH acting at V2 receptors raises cAMP and inserts aquaporin-2 channels into the apical membrane of collecting-duct principal cells. Water then exits basolaterally through constitutive channels.

Option by option

  • A. Na-K-2Cl cotransporter

    Na-K-2Cl cotransporter is in thick ascending limb and targeted by loop diuretics.

  • B. ENaC

    ENaC mediates sodium entry and is regulated by aldosterone.

  • C. Aquaporin-1

    AQP1 is constitutively expressed in proximal tubule and descending limb.

  • D. Aquaporin-2 (correct)

    Correct. AQP2 is the regulated apical water channel.

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, Aquaporin-2. ADH acting at V2 receptors raises cAMP and inserts aquaporin-2 channels into the apical membrane of collecting-duct principal cells.

Why is "Na-K-2Cl cotransporter" not the answer?

Na-K-2Cl cotransporter is in thick ascending limb and targeted by loop diuretics.

Why is "ENaC" not the answer?

ENaC mediates sodium entry and is regulated by aldosterone.

Why is "Aquaporin-1" not the answer?

AQP1 is constitutively expressed in proximal tubule and descending limb.

What concept does this question test?

It tests Renal physiology: ADH in Physiology. Water then exits basolaterally through constitutive channels.

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 Renal physiology: ADH?

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.