The lymphatic system is a complex network of thin vessels, capillaries, valves, ducts, nodes, and organs that runs throughout the body, helping protect and maintain the internal fluids system of the entire body by both producing and filtering lymph, and by producing various blood cells. The three main purposes of the lymphatic system are to drain fluid back into the bloodstream from the tissues, to filter lymph, and to fight infections.

The lymphatic system includes the spleen, the thymus, the lymph nodes, and the lymph ducts. It has a major component in immunity.

The lymphatic system branches through all parts of the body carrying lymph, a clear, watery, blood plasma fluid containing proteins, leucocytes, and glucose. Lymph contains red blood cells and many white blood cells, especially lymphocytes. Lymphocytes are the cells that attack bacteria in the blood. Lymph is produced by small bean-shaped lymph nodes...