Gastrointestinal: gastric acid and PPI action: 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 · Gastrointestinal: gastric acid and PPI action

Sample item

A 40-year-old with a duodenal ulcer is started on omeprazole. Compared with an H2 blocker, why is acid suppression more complete, including after meals?

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

The answer and the reasoning

B. It irreversibly blocks the final common step, the H+/K+ ATPase

Histamine, acetylcholine and gastrin all converge on the proton pump. A proton pump inhibitor blocks the last step, so stimulation by any of them is blocked. H2 blockers prevent only the histamine route.

Option by option

  • A. It blocks histamine receptors only

    H2 blockade is the action of ranitidine, which leaves the other stimuli active.

  • B. It irreversibly blocks the final common step, the H+/K+ ATPase (correct)

    Correct. Blocking the proton pump stops acid from every stimulus.

  • C. It blocks gastrin receptors only

    Gastrin receptor antagonism is not the mechanism and would leave other pathways.

  • D. It blocks muscarinic receptors only

    Muscarinic blockade is incomplete because histamine and gastrin still act.

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, It irreversibly blocks the final common step, the H+/K+ ATPase. Histamine, acetylcholine and gastrin all converge on the proton pump.

Why is "It blocks histamine receptors only" not the answer?

H2 blockade is the action of ranitidine, which leaves the other stimuli active.

Why is "It blocks gastrin receptors only" not the answer?

Gastrin receptor antagonism is not the mechanism and would leave other pathways.

Why is "It blocks muscarinic receptors only" not the answer?

Muscarinic blockade is incomplete because histamine and gastrin still act.

What concept does this question test?

It tests Gastrointestinal: gastric acid and PPI action in Physiology. A proton pump inhibitor blocks the last step, so stimulation by any of them is blocked. H2 blockers prevent only the histamine route.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Gastrointestinal: gastric acid and PPI action?

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.