Cardiovascular system: venous return curve: 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 system: venous return curve

Sample item

A hypovolaemic patient receives a rapid litre of intravenous saline. On a venous return curve plotted against right atrial pressure, what change results?

AA parallel rightward shift because mean systemic filling pressure risesBA leftward shift because mean systemic filling pressure fallsCA flatter curve because resistance to venous return risesDNo change because right atrial pressure alone sets venous return

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

The answer and the reasoning

A. A parallel rightward shift because mean systemic filling pressure rises

Venous return depends on the gradient between mean systemic filling pressure and right atrial pressure, divided by the resistance to venous return. Raising blood volume or venous tone increases the mean systemic filling pressure and shifts the curve to the right without changing the slope. Hypovolaemia shifts it to the left.

Option by option

A. A parallel rightward shift because mean systemic filling pressure rises (correct)
Correct. More volume raises mean systemic filling pressure and shifts the curve rightward.
B. A leftward shift because mean systemic filling pressure falls
A leftward shift would follow volume loss or venodilation.
C. A flatter curve because resistance to venous return rises
A change in slope reflects a change in resistance to venous return, which volume loading does not alter.
D. No change because right atrial pressure alone sets venous return
Venous return also depends on the upstream filling pressure, so right atrial pressure is not the sole determinant.

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, A parallel rightward shift because mean systemic filling pressure rises. Venous return depends on the gradient between mean systemic filling pressure and right atrial pressure, divided by the resistance to venous return.

Why is "A leftward shift because mean systemic filling pressure falls" not the answer?

A leftward shift would follow volume loss or venodilation.

Why is "A flatter curve because resistance to venous return rises" not the answer?

A change in slope reflects a change in resistance to venous return, which volume loading does not alter.

Why is "No change because right atrial pressure alone sets venous return" not the answer?

Venous return also depends on the upstream filling pressure, so right atrial pressure is not the sole determinant.

What concept does this question test?

It tests Cardiovascular system: venous return curve in Physiology. Raising blood volume or venous tone increases the mean systemic filling pressure and shifts the curve to the right without changing the slope. Hypovolaemia shifts it to the left.

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 Cardiovascular system: venous return curve?

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.