Question

Which of the following is NOT considered primary lymphoid tissue?

1) Draining lymph node
2) Thymus
3) Peyer's patch
4) Choices A and C are not primary lymphoid tissue.
5) None of the above is primary lymphoid tissue.

Answer 1

Primary lymphoid tissues are the bone marrow and the thymus gland. Secondary lymphoid tissues include the tonsils, spleen, and lymph nodes.

Step-by-step explanation:

The primary lymphoid tissues are the bone marrow and the thymus gland, where lymphocytes mature and develop.

Secondary lymphoid tissues include the tonsils, spleen, and lymph nodes, which filter lymph and store lymphocytes.

Peyer's patches and bronchus-associated lymphoid tissue (BALT) are examples of secondary lymphoid tissues, not primary lymphoid tissues.