Michelle Hacker, age 16, of Gadsden, Ala., for her question:
WHAT DOES THE SPLEEN DO?
The spleen is a flattened, oblong, gland like organ that is located in the upper left abdominal cavity, in contact with the pancreas, the diaphragm and the left kidney, and supported by bands of fibers that are attached to the membrane lining ofå the abdominal cavity.
As an integral part of the lymphatic and vascular systems, the spleen occupies a unique position that allows it to remove disease producing organisms and worn out red blood cells from the bloodstream.
The spleen also removes the iron from the hemoglobin of red blood cells for later use in the body and it removes such toxic waste materials as bile pigments for excretion as bile by the liver. In addition, the spleen produces antibodies against various disease organisms and manufactures a variety of blood cells.In some animals, but not in humans, the spleen stores red blood cells and feeds them into the circulation to maintain the volume of blood in case of hemorrhage. The spleen is no longer regarded as an endocrine gland because it apparently produces no secretions, although in disease it may elaborate a hormone that affects the production of red blood cells in the bone marrow. Some people are born without spleens. In the unborn child, the organ functions primarily to produce red blood cells, a function that normally ceases after birth but that may be resumed later if diseases slow down this function in the bone marrow.
The spleen varies in size but in an adult human it is about five inches long, up to four inches wide and about an inch and a half thick. It weighs approximately seven ounces. Many diseases affect the spleen. In splenomegaly, the spleen enlarges, sometimes to an enormous size. This condition usually indicates disease elsewhere in the body. In hypersplenism, a malfunctioning or hyperactive spleen may so increase its normal rate of destroying red blood cells as to cause a variety of hemolytic anemias. Hemorrhage of an enlarged spleen may magnify anemia and also cause an iron deficiency. The condition of hyperactive spleen may sometimes be corrected by treatment with radiation or corticosteroids, or steroids that are extracted from the adrenal cortex. Abscesses are treated with broad spectrum antibiotics and surgical drainage. In serious cases, surgical removal of the spleen may be required. It is inevitable if the spleen or the aplenic artery ruptures. Other organs produce greater volumes of antibody and the bone marrow surpasses the spleen in producing blood cells. Also, the liver, the pituitary and the adrenal glands destroy more bacterial invaders than the spleen.