Histology: lymph node zones: practice question

A Anatomy 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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Anatomy · Histology: lymph node zones

Sample item

A newborn has hypocalcaemic seizures, a conotruncal cardiac defect and an absent thymic shadow, and a 22q11.2 deletion is found. Which zone of a lymph node would be expected to be depleted?

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

The answer and the reasoning

C. Paracortex, the T-cell zone

In DiGeorge syndrome the third and fourth pharyngeal pouches develop abnormally, causing thymic hypoplasia, low T-cell numbers, hypoparathyroidism and conotruncal heart defects. The paracortex, where T cells and dendritic cells reside, is therefore depleted, whereas follicles remain. Absent follicles occur instead in X-linked agammaglobulinaemia.

Option by option

  • A. Medullary cords containing plasma cells

    Medullary cords hold plasma cells, which are depleted in B-cell deficiencies, not T-cell deficiency.

  • B. Cortical follicles, the B-cell zone

    Cortical follicles are B-cell areas and are preserved in DiGeorge syndrome.

  • C. Paracortex, the T-cell zone (correct)

    Correct. The paracortex is the thymus-dependent T-cell area and is depleted when the thymus is absent.

  • D. Germinal centres of secondary follicles

    Germinal centres are sites of B-cell proliferation and are not the classically depleted zone in DiGeorge syndrome.

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.

More Anatomy questions

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is C, Paracortex, the T-cell zone. In DiGeorge syndrome the third and fourth pharyngeal pouches develop abnormally, causing thymic hypoplasia, low T-cell numbers, hypoparathyroidism and conotruncal heart defects.

Why is "Medullary cords containing plasma cells" not the answer?

Medullary cords hold plasma cells, which are depleted in B-cell deficiencies, not T-cell deficiency.

Why is "Cortical follicles, the B-cell zone" not the answer?

Cortical follicles are B-cell areas and are preserved in DiGeorge syndrome.

Why is "Germinal centres of secondary follicles" not the answer?

Germinal centres are sites of B-cell proliferation and are not the classically depleted zone in DiGeorge syndrome.

What concept does this question test?

It tests Histology: lymph node zones in Anatomy. The paracortex, where T cells and dendritic cells reside, is therefore depleted, whereas follicles remain. Absent follicles occur instead in X-linked agammaglobulinaemia.

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 Histology: lymph node zones?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy 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.