Question

Write short note on primary and secondary lymphoid organs.

Hint:

The primary lymphoid organs are involved in the development and maturation of lymphocytes, while secondary lymphoid organs initiate immune responses.

Answer 1

Primary lymphoid organs are the sites where lymphocytes are produced and mature. These include: 1. Bone marrow: It is the primary site for the production of all blood cells, including lymphocytes. 2. Thymus: It is where T lymphocytes (T cells) mature and gain the ability to recognize specific antigens. Secondary lymphoid organs are the sites where immune responses are initiated. These include: 1. Lymph nodes: Small, bean-shaped structures that filter lymph and trap pathogens, allowing lymphocytes to respond to infections. 2. Spleen: Filters blood, removes old blood cells, and helps initiate immune responses against blood-borne pathogens. 3. Mucosa-associated lymphoid tissues (MALT): Found in areas like the intestines and respiratory tract, where they protect mucosal surfaces.
Final Answer: Primary lymphoid organs include bone marrow and thymus, while secondary lymphoid organs include lymph nodes, spleen, and MALT.