Reproduction: blood-testis barrier: 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 · Reproduction: blood-testis barrier

Sample item

A 28-year-old man has severe oligospermia and high titres of antisperm antibodies after a crush injury to the testis. Which normal structure protects developing haploid germ cells from the immune system?

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

The answer and the reasoning

C. Tight junctions between adjacent Sertoli cells

Sertoli cells form tight junctions that divide the seminiferous epithelium into a basal compartment and an adluminal compartment, the blood-testis barrier. Meiotic and haploid cells appear after puberty and are immunologically foreign, so they are isolated in the adluminal compartment. Trauma or infection can break the barrier and lead to antisperm antibodies.

Option by option

  • A. The tunica albuginea

    The tunica albuginea is the outer capsule and does not isolate germ cells within tubules.

  • B. Peritubular myoid cells only

    Myoid cells contract the tubule, and the barrier is formed by the Sertoli cells.

  • C. Tight junctions between adjacent Sertoli cells (correct)

    Correct. Sertoli cell junctions form the barrier.

  • D. Tight junctions between Leydig cells

    Leydig cells lie in the interstitium and secrete testosterone; they do not form the barrier.

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, Tight junctions between adjacent Sertoli cells. Sertoli cells form tight junctions that divide the seminiferous epithelium into a basal compartment and an adluminal compartment, the blood-testis barrier.

Why is "The tunica albuginea" not the answer?

The tunica albuginea is the outer capsule and does not isolate germ cells within tubules.

Why is "Peritubular myoid cells only" not the answer?

Myoid cells contract the tubule, and the barrier is formed by the Sertoli cells.

Why is "Tight junctions between Leydig cells" not the answer?

Leydig cells lie in the interstitium and secrete testosterone; they do not form the barrier.

What concept does this question test?

It tests Reproduction: blood-testis barrier in Physiology. Meiotic and haploid cells appear after puberty and are immunologically foreign, so they are isolated in the adluminal compartment. Trauma or infection can break the barrier and lead to antisperm antibodies.

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 Reproduction: blood-testis barrier?

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.