Question

Why are lymph nodes and bone marrow called lymphoid organs

Answer 1

Because of their roles in the production of B and T cells, the thymus and bone marrow are considered primary lymphoid organs. Secondarylymphoid organs include lymph nodesand spleen, which filter lymph and blood, respectively, and where naïve B and T cells are introduced to antigens.

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Answer 2

Bone marrow and the thymus, a glandsituated above the heart and behind the breast bone, are so-called primarylymphoid organs. The bone marrowproduces defense cells. ... Theseorgans include the lymph nodes, the spleen, the tonsils and other specialized tissues in the mucous membranes of the bowel