Question

Why is lymph node and bone marrow called lymphoid organs? Explain the function of each one

Answer 1

Lymphoid structures can be found throughout the body. While all lymphoid structures are capable of lymphocyte production, the red bone marrow and thymus are considered primary lymphoid organs because all WBCs, especially lymphocytes, originate in these organs. After production in the red bone marrow most lymphocytes and other immune cells go to secondary lymphoid organs, such as the lymph nodes and spleen that become the sites of proliferation of lymphocytes and immune responses.