Question

How is the immune system anatomically organised? (Organs, recirculation etc)

Answer 1

Lymphoid organs

Origin, maturation and proliferation of lymphocyte occur in these organs.Primary lymphoid organs are thymus and bone marrow. In the primary lymphoid organs immature lymphocyte differentiate to form antigen sensitive lymphocytes. Bone marrow produces all blood cells.Thymus undergo degeneration while we grow. Both these primary organs help in development and maturation of T lymphocytes.

Secondary lymphoid organs are spleen, lymph nodes, tonsils, payer's patches and appendix. This is the sites for interaction between antigens and lymphocyte occur. Bean shaped spleen contains lymphocytes and phagocytes and it act as filter of blood. Spleen is the graveyard of RBC. Lymph nodes are located in various sites of lymphatic system. Lymph node trap antigens and allow it into lymph.Lymphocyte activation occur due to these antigens.Lymphatic system collects tissue fluid and drain it back to major veins. Lymph contains specialised lymphocytes and it is also an important carrier of nutrients and hormones. Mucosa associated lymphoid tissue or MALT present in respiratory, alimentary and urogenital tracts of the body constitute 50% of total lymphoid tissues.