Lymphatic system

In mammals including humans, the lymphatic vessels (or lymphatics) are a network of thin tubes that branch, like blood vessels, into tissues throughout the body. Lymphatic vessels carry lymph, a colorless, watery fluid originating from interstitial fluid (fluid in the tissues). The lymphatic system transports infection-fighting cells called lymphocytes, is involved in the removal of foreign matter and cell debris by phagocytes and is part of the body's immune system. It also transports fats from the small intestine to the blood.

Primary lymphoid organs

The thymus and bone marrow are the primary lymphatic organs. Lymphocytes are produced by stem cells in the bone marrow and then migrate to either the thymus or bone marrow where they mature. T-lymphocytes undergo maturation in the thymus (hence their name), and B-lymphocytes undergo maturation in the bone marrow. After maturation, both B- and T-lymphocytes circulate in the lymph and accumulate in secondary lymphoid organs, where they await recognition of antigens.

Related Topics:
Thymus - Bone marrow - Antigen

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