Cardiac physiology: Frank-Starling: 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 · Cardiac physiology: Frank-Starling

Sample item

An intravenous fluid bolus increases the end-diastolic volume of the ventricle in a healthy person. Which change follows, by the Frank-Starling mechanism?

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

The answer and the reasoning

D. Increased stroke volume because of greater sarcomere stretch and calcium sensitivity

Within physiological limits, greater ventricular filling stretches sarcomeres towards their optimal length and raises myofilament sensitivity to calcium, so the force of contraction and stroke volume increase. This matches output to venous return without neural input.

Option by option

  • A. Decreased stroke volume because of overstretched myofilaments

    Overstretch with falling output occurs only far beyond the normal physiological range, for example in severe failure.

  • B. Decreased contractility because of reduced calcium release

    Stretch increases, not reduces, calcium sensitivity and force.

  • C. No change in stroke volume until heart rate rises

    The mechanism works beat by beat and does not depend on a rise in heart rate.

  • D. Increased stroke volume because of greater sarcomere stretch and calcium sensitivity (correct)

    Correct. Greater preload lengthens the sarcomeres and increases the stroke volume.

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, Increased stroke volume because of greater sarcomere stretch and calcium sensitivity. Within physiological limits, greater ventricular filling stretches sarcomeres towards their optimal length and raises myofilament sensitivity to calcium, so the force of contraction and stroke volume increase.

Why is "Decreased stroke volume because of overstretched myofilaments" not the answer?

Overstretch with falling output occurs only far beyond the normal physiological range, for example in severe failure.

Why is "Decreased contractility because of reduced calcium release" not the answer?

Stretch increases, not reduces, calcium sensitivity and force.

Why is "No change in stroke volume until heart rate rises" not the answer?

The mechanism works beat by beat and does not depend on a rise in heart rate.

What concept does this question test?

It tests Cardiac physiology: Frank-Starling in Physiology. This matches output to venous return without neural input.

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 Cardiac physiology: Frank-Starling?

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.