Which organ stores memory lymphocytes?

Correct Answer: C

Rationale: Lymph nodes store memory cells; thymus matures, spleen filters, marrow produces.

Correct Answer: C

Rationale: Lymph nodes activate B cells; thymus matures T cells, spleen filters, marrow produces.

Correct Answer: A

Rationale: The thymic medulla is supported by epithelioreticular cells forming a reticular framework.

Correct Answer: D

Rationale: Bicuspid valves in lymphatic vessels ensure unidirectional lymph flow; tricuspid, aortic, and pulmonary valves are in the heart.

Correct Answer: C

Rationale: The spleen's capsule contains vessels, nerves, muscle , dense C.T. , and trabeculae ; it's thick at the hilum, not thin (C is incorrect).