Lymphatic System

The lymphatic system teams up with your circulatory and immune systems to help your body fight off bacteria and viruses. Lymph itself is a clear fluid that contains white blood cells. Your lymphatic system includes the thymus gland, tonsils, spleen, bone marrow, lymphatic vessels that serve as the lymph transport system and lymph nodes, which cluster along the lymphatic vessels to filter the lymph.

* Bone marrow, a substance found inside most of our bones, produces red blood cells. It needs the mineral iron for red blood cell production. Because women lose iron whenever they menstruate, 3 percent of us are tired out from iron-deficiency anemia. (To get more iron in your diet, see "Stoke up on iron" on page 30.)

Infection-fighting white blood cells, lymphocytes, travel the lymphatic system in a stream of lymph fluid. They journey through a network of vessels, the smallest of which are the lymphatic capillaries. Here''''s how the tiny lymphatic capillaries are threaded among the lacework of blood capillaries.

* Lymph is rich in lymphocytes--warrior white cells that battle bacterial and viral infection. Lymphocytes also produce memory cells, stored in the lymph nodes, that remember the body''''s invader and help protect against future attacks. (To learn what you can do to help strengthen your immune system, see the Nutrition chapter on page 266.)

* Lymphocytes multiply and are an active part of the immune system. Sometimes the immune system falters, however, and turns against the body''''s own tissue, as in the autoimmune disease rheumatoid arthritis. (To relieve arthritis pain, see "Anti-arthritis Advice" on page 180.)

* Leukemia is a cancer of the blood-forming organs. The bone marrow, lymph nodes and spleen go awry, producing too many abnormal white blood cells and shortchanging your system of functional, disease-fighting white blood cells. (See "What Can Go Wrong" on page 30 to find out its symptoms.)

* The simplest of the lymphatic organs, the almond-sized tonsils are considered expendable. Although fewer than 10 percent of all tonsillectomies are performed on adults, you may be helped by the surgery if you get repeated infections. (See "When to Bid Tonsils Good-Bye" on page 416.)