Histology: lymphoid tissue: 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: lymphoid tissue

Sample item

An infant has severe T-cell deficiency due to thymic aplasia. In a lymph node biopsy, which region would be depleted of lymphocytes?

AParacortexBSubcapsular sinusCMedullary cordsDPrimary follicles of the outer cortex

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

The answer and the reasoning

A. Paracortex

The paracortex, between the follicles and the medulla, is the T-cell zone of the lymph node and contains the high endothelial venules through which lymphocytes enter. It is depleted in T-cell deficiencies such as thymic aplasia, whereas follicles remain. B cells live in follicles and plasma cells in the medullary cords.

Option by option

A. Paracortex (correct)
Correct. The paracortex is the T-cell area and is depleted when the thymus fails to produce T cells.
B. Subcapsular sinus
The subcapsular sinus is a lymph channel lined by macrophages and is not a lymphocyte zone.
C. Medullary cords
Medullary cords contain plasma cells and B cells that secrete antibody.
D. Primary follicles of the outer cortex
Primary follicles hold B cells, which develop in bone marrow and are not directly depleted.

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 Anatomy question

What is the answer to this Anatomy question?

The best answer is A, Paracortex. The paracortex, between the follicles and the medulla, is the T-cell zone of the lymph node and contains the high endothelial venules through which lymphocytes enter.

Why is "Subcapsular sinus" not the answer?

The subcapsular sinus is a lymph channel lined by macrophages and is not a lymphocyte zone.

Why is "Medullary cords" not the answer?

Medullary cords contain plasma cells and B cells that secrete antibody.

Why is "Primary follicles of the outer cortex" not the answer?

Primary follicles hold B cells, which develop in bone marrow and are not directly depleted.

What concept does this question test?

It tests Histology: lymphoid tissue in Anatomy. It is depleted in T-cell deficiencies such as thymic aplasia, whereas follicles remain. B cells live in follicles and plasma cells in the medullary cords.

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: lymphoid tissue?

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.