Spleen is a soft, purplish organ located behind and to the left of the stomach in human beings. A person’s spleen is about the size of his or her fist. Scientists do not fully understand all of the spleen’s functions. However, the organ plays an important part in both the circulatory system and the immune system.
The spleen helps filter useless substances from the blood. Blood cells form in the bone marrow and circulate in the body for some time before they die. Blood passing through the spleen travels through a maze of spongelike spaces called sinusoids. There, large cells called macrophages surround and destroy old or damaged blood cells.
The spleen also helps the body fight infection. Macrophages in the spleen rid the blood of certain parasites and bacteria. In addition, the spleen contains clumps of white blood cells called lymphocytes, which release special proteins into the blood. These proteins, called antibodies, weaken or kill bacteria, viruses, and other organisms that cause infection.
Sometimes, surgeons remove a patient’s spleen in an operation called a splenectomy. The spleen may be removed if it is damaged or overactive, or if the patient has cancer of the lymphatic system.
A person’s spleen may be damaged by a blow to the abdomen. A damaged spleen can sometimes cause a serious loss of blood and result in death. In most cases, surgeons can repair a damaged spleen. However, a splenectomy is sometimes necessary to stop the bleeding. The spleen may also become overactive and filter useful substances from the blood. The loss of these substances may result in anemia, bleeding, or infection. In some cases, a splenectomy improves or corrects the disorder. Cancer of the lymphatic system may also affect the spleen, thus requiring surgical removal of the organ.
A splenectomy causes no noticeable ill effects in most patients. But in a few patients, especially children, removal of the spleen leads to serious infection. For this reason, a patient who has had a splenectomy should receive a special vaccination that reduces the chances of infection.
