Endocrine: adrenal cortex zones: 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 · Endocrine: adrenal cortex zones

Sample item

A man with a pituitary macroadenoma has fatigue, hypoglycaemia and low blood pressure. His serum cortisol is low, but his potassium and plasma aldosterone are normal. Which explanation is correct?

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

The answer and the reasoning

B. The zona glomerulosa is regulated mainly by angiotensin II and potassium, so aldosterone secretion is preserved when ACTH is low

The cortex has three zones: glomerulosa (aldosterone), fasciculata (cortisol) and reticularis (androgens). ACTH maintains the fasciculata and reticularis, which atrophy in secondary adrenal insufficiency, whereas the glomerulosa responds mainly to angiotensin II and plasma potassium. Therefore hyperkalaemia and volume depletion are minimal in pituitary disease unlike in Addison disease.

Option by option

  • A. ACTH is the main regulator of aldosterone, so its level should be low

    ACTH has only a minor, permissive role in aldosterone secretion.

  • B. The zona glomerulosa is regulated mainly by angiotensin II and potassium, so aldosterone secretion is preserved when ACTH is low (correct)

    Correct. Different regulation preserves aldosterone.

  • C. The zona reticularis secretes aldosterone independently of ACTH

    The reticularis makes androgens, not aldosterone.

  • D. The zona glomerulosa is the main source of cortisol and is spared

    Cortisol comes from the zona fasciculata, not the glomerulosa.

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 B, The zona glomerulosa is regulated mainly by angiotensin II and potassium, so aldosterone secretion is preserved when ACTH is low. The cortex has three zones: glomerulosa (aldosterone), fasciculata (cortisol) and reticularis (androgens).

Why is "ACTH is the main regulator of aldosterone, so its level should be low" not the answer?

ACTH has only a minor, permissive role in aldosterone secretion.

Why is "The zona reticularis secretes aldosterone independently of ACTH" not the answer?

The reticularis makes androgens, not aldosterone.

Why is "The zona glomerulosa is the main source of cortisol and is spared" not the answer?

Cortisol comes from the zona fasciculata, not the glomerulosa.

What concept does this question test?

It tests Endocrine: adrenal cortex zones in Physiology. ACTH maintains the fasciculata and reticularis, which atrophy in secondary adrenal insufficiency, whereas the glomerulosa responds mainly to angiotensin II and plasma potassium. Therefore hyperkalaemia and volume depletion are minimal in pituitary disease unlike in Addison disease.

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 Endocrine: adrenal cortex zones?

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.