The lymph system (lymphatic system) is a network of tissues and organs whose primary function is to produce and transport lymph throughout the body. Lymph is a clear fluid that contains white blood cells that helps the body fight bacteria and get rid of toxins. It is produced in the lymph nodes, and is transported through lymph vessels.
Lymph nodes are found in the underarm, neck, and groin area, and can usually be felt as a tender swelling when there is an infection. The tonsils, spleen, and thymus are also part of the lymph system. The tonsils are actually clusters of lymphatic cells. The spleen contains the white blood cells that help fight infection, and the thymus is where T-cells mature, which are special cancer-fighting cells.