Female reproductive 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 · Female reproductive physiology

Sample item

In the middle of the menstrual cycle, which event triggers the preovulatory LH surge?

ASustained high oestradiol from the dominant follicle acting by positive feedbackBA rise in inhibin B suppressing GnRHCA sudden fall in oestradiolDA rise in progesterone from the corpus luteum

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

The answer and the reasoning

A. Sustained high oestradiol from the dominant follicle acting by positive feedback

In the late follicular phase a dominant follicle secretes large amounts of oestradiol. Once this is sustained above a threshold, feedback switches from negative to positive and the anterior pituitary releases an LH surge, which triggers ovulation.

Option by option

A. Sustained high oestradiol from the dominant follicle acting by positive feedback (correct)
Correct. Sustained high oestradiol produces positive feedback and the LH surge.
B. A rise in inhibin B suppressing GnRH
Inhibin B suppresses FSH rather than causing the LH surge.
C. A sudden fall in oestradiol
A fall in oestradiol would remove the stimulus and does not trigger the surge.
D. A rise in progesterone from the corpus luteum
Progesterone from the corpus luteum rises only after ovulation, so it cannot trigger the surge.

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, Sustained high oestradiol from the dominant follicle acting by positive feedback. In the late follicular phase a dominant follicle secretes large amounts of oestradiol.

Why is "A rise in inhibin B suppressing GnRH" not the answer?

Inhibin B suppresses FSH rather than causing the LH surge.

Why is "A sudden fall in oestradiol" not the answer?

A fall in oestradiol would remove the stimulus and does not trigger the surge.

Why is "A rise in progesterone from the corpus luteum" not the answer?

Progesterone from the corpus luteum rises only after ovulation, so it cannot trigger the surge.

What concept does this question test?

It tests Female reproductive physiology in Physiology. Once this is sustained above a threshold, feedback switches from negative to positive and the anterior pituitary releases an LH surge, which triggers ovulation.

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 Female reproductive 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.