Lymph is a clear to yellowish watery fluid which is found throughout the body. It circulates through body tissues picking up fats, bacteria, and other unwanted materials, filtering these substances out through the lymphatic system. Thus the circulation of lymph through the body is an important part of immune system. The lymph circulates freely through the body, bathing cells in needed nutrients and oxygen while it collects harmful materials for disposal.
Lymph nodes produce immune cells that help the body fight infection. When bacteria are recognized in the lymph fluid, the lymph nodes produce more infection-fighting white blood cells, which causes the nodes to swell.
The lymph system is a network of organs, lymph nodes, lymph ducts, and lymph vessels that produce and transport lymph from tissues to the bloodstream. The lymph is formed when the interstitial fluid is collected through lymph capillaries. It is then transported though lymph vessels to lymph nodes before emptying ultimately into the right or the left subclavian vein, where it mixes back with blood.