Cardiovascular physiology: 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 · Cardiovascular physiology

Sample item

Which cardiac structure normally has the highest intrinsic pacemaker rate?

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

The answer and the reasoning

B. Sinoatrial node

The sinoatrial node has the fastest spontaneous phase-4 depolarization and therefore normally sets heart rate; slower latent pacemakers can take over if SA-node activity or conduction fails.

Option by option

  • A. Atrioventricular node

    AV node has a slower intrinsic escape rate.

  • B. Sinoatrial node (correct)

    Correct: SA node normally dominates because it fires fastest.

  • C. Purkinje fibers

    Purkinje fibers have the slowest of these intrinsic pacemaker rates.

  • D. Bundle of His

    His bundle automaticity is slower than SA-node automaticity.

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, Sinoatrial node. The sinoatrial node has the fastest spontaneous phase-4 depolarization and therefore normally sets heart rate; slower latent pacemakers can take over if SA-node activity or conduction fails.

Why is "Atrioventricular node" not the answer?

AV node has a slower intrinsic escape rate.

Why is "Purkinje fibers" not the answer?

Purkinje fibers have the slowest of these intrinsic pacemaker rates.

Why is "Bundle of His" not the answer?

His bundle automaticity is slower than SA-node automaticity.

What concept does this question test?

It tests Cardiovascular physiology in Physiology. The correct option holds because: Correct: SA node normally dominates because it fires fastest.

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 Cardiovascular physiology?

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.