Labour and delivery: myometrial gap junctions: practice question

A OBG 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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OBG · Labour and delivery: myometrial gap junctions

Sample item

Near term, uterine contractions become strong and coordinated. Which myometrial change mainly allows contractions to spread synchronously across the uterus?

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

The answer and the reasoning

C. Increased gap junctions formed by connexin-43

Near term the myometrium forms abundant gap junctions (connexin-43) that couple the cells electrically so contraction spreads as a wave. Oxytocin receptors and prostaglandin receptors also increase, and intracellular calcium rises to drive actin-myosin interaction.

Option by option

  • A. Reduced oxytocin receptor expression

    Oxytocin receptor expression rises sharply, making the uterus more sensitive.

  • B. Increased number of tight junctions between decidual cells

    Tight junctions seal epithelia and do not allow the spread of contractile signals.

  • C. Increased gap junctions formed by connexin-43 (correct)

    Correct. Gap junctions allow electrical coupling and synchronised contractions.

  • D. Fall in intracellular calcium

    Contraction needs a rise, not a fall, in intracellular calcium.

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 OBG question

What is the answer to this OBG question?

The best answer is C, Increased gap junctions formed by connexin-43. Near term the myometrium forms abundant gap junctions (connexin-43) that couple the cells electrically so contraction spreads as a wave.

Why is "Reduced oxytocin receptor expression" not the answer?

Oxytocin receptor expression rises sharply, making the uterus more sensitive.

Why is "Increased number of tight junctions between decidual cells" not the answer?

Tight junctions seal epithelia and do not allow the spread of contractile signals.

Why is "Fall in intracellular calcium" not the answer?

Contraction needs a rise, not a fall, in intracellular calcium.

What concept does this question test?

It tests Labour and delivery: myometrial gap junctions in OBG. Oxytocin receptors and prostaglandin receptors also increase, and intracellular calcium rises to drive actin-myosin interaction.

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 Labour and delivery: myometrial gap junctions?

Learn management algorithms as steps: PPH, eclampsia, ectopic pregnancy. Then use the flashcards and the other OBG 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.