Out of the misconceptions The lymphatic system is composed of lymph, lymphatic tracts, lymphatic tissues and lymphatic organs. Lymph is the fluid contained within the lymphatic sinuses of the lymphatic vessels and lymph nodes. Lymphatic organs include lymph nodes, thymus, spleen and tonsils. A lymph node is a small, grayish-red body of varying size, round or oval in shape, which is bulging on one side and depressed on the other. Lymph nodes are mostly distributed in groups, and the number is not constant; there are about 400~450 lymph nodes in young people. Its main function is to filter lymph, produce lymphocytes and carry out immune response, and it plays an important role in lymphatic drainage. The lymph nodes are important immune organs of the body. Various factors such as infection by various pathogenic microorganisms, chemical drugs, foreign poisons, foreign bodies and the body’s own metabolites can cause the proliferation of cellular components such as lymphocytes in the lymph nodes, resulting in enlargement of the lymph nodes. The proliferation of lymph nodes can be reactive or tumorigenic.