Neurophysiology and special senses: aqueous humour: 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 · Neurophysiology and special senses: aqueous humour

Sample item

A patient with raised intraocular pressure is given acetazolamide. It reduces aqueous humour formation in the ciliary epithelium by inhibiting which enzyme?

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

The answer and the reasoning

C. Carbonic anhydrase

Aqueous humour is secreted by the ciliary epithelium, and bicarbonate formation by carbonic anhydrase supports this secretion. Inhibiting the enzyme reduces aqueous production and lowers intraocular pressure.

Option by option

  • A. Acetylcholinesterase

    Acetylcholinesterase is inhibited by miotics and is not the target of acetazolamide.

  • B. Monoamine oxidase

    Monoamine oxidase degrades amines and is not the target of acetazolamide.

  • C. Carbonic anhydrase (correct)

    Correct. Carbonic anhydrase supports aqueous secretion, and inhibition lowers its formation.

  • D. Angiotensin-converting enzyme

    Angiotensin-converting enzyme is not involved in aqueous formation.

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 C, Carbonic anhydrase. Aqueous humour is secreted by the ciliary epithelium, and bicarbonate formation by carbonic anhydrase supports this secretion.

Why is "Acetylcholinesterase" not the answer?

Acetylcholinesterase is inhibited by miotics and is not the target of acetazolamide.

Why is "Monoamine oxidase" not the answer?

Monoamine oxidase degrades amines and is not the target of acetazolamide.

Why is "Angiotensin-converting enzyme" not the answer?

Angiotensin-converting enzyme is not involved in aqueous formation.

What concept does this question test?

It tests Neurophysiology and special senses: aqueous humour in Physiology. Inhibiting the enzyme reduces aqueous production and lowers intraocular pressure.

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 Neurophysiology and special senses: aqueous humour?

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.