Renal and acid–base: bladder storage phase: 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.

Try it

Physiology · Renal and acid–base: bladder storage phase

Sample item

During the storage phase of the bladder, sympathetic activity through the hypogastric nerve (T10 to L2) helps continence. Which combination of effects does it produce?

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

The answer and the reasoning

C. Detrusor relaxation and contraction of the internal urethral sphincter

In the storage phase, sympathetic fibres relax the detrusor through beta-3 receptors and contract the bladder neck and internal sphincter through alpha-1 receptors. The external sphincter, a striated muscle supplied by the pudendal nerve, is under voluntary control. Voiding needs parasympathetic detrusor contraction.

Option by option

  • A. Detrusor contraction and relaxation of the internal urethral sphincter

    Detrusor contraction with sphincter relaxation is the parasympathetic voiding pattern.

  • B. Detrusor contraction and contraction of the external urethral sphincter

    Detrusor contraction would produce voiding, and the external sphincter is a somatic structure.

  • C. Detrusor relaxation and contraction of the internal urethral sphincter (correct)

    Correct. Sympathetic action favours storage by relaxing the detrusor and closing the internal sphincter.

  • D. Detrusor relaxation and relaxation of the external urethral sphincter

    The external sphincter is somatic and is not relaxed by sympathetic nerves; relaxing it would favour voiding.

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.

More Physiology questions

Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is C, Detrusor relaxation and contraction of the internal urethral sphincter. In the storage phase, sympathetic fibres relax the detrusor through beta-3 receptors and contract the bladder neck and internal sphincter through alpha-1 receptors.

Why is "Detrusor contraction and relaxation of the internal urethral sphincter" not the answer?

Detrusor contraction with sphincter relaxation is the parasympathetic voiding pattern.

Why is "Detrusor contraction and contraction of the external urethral sphinct…" not the answer?

Detrusor contraction would produce voiding, and the external sphincter is a somatic structure.

Why is "Detrusor relaxation and relaxation of the external urethral sphincter" not the answer?

The external sphincter is somatic and is not relaxed by sympathetic nerves; relaxing it would favour voiding.

What concept does this question test?

It tests Renal and acid–base: bladder storage phase in Physiology. The external sphincter, a striated muscle supplied by the pudendal nerve, is under voluntary control. Voiding needs parasympathetic detrusor contraction.

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 and acid–base: bladder storage phase?

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.