The spleen is an internal organ, about the size of a fist, found in the human abdomen. The spleen functions as part of the immune system and contributes to the production and storage of blood cells as part of the circulatory system. Although the spleen is an important organ, it is not vital for human survival.
Function of the Spleen
The majority of the spleen's functions are related to the immune system or the blood supply. The spleen removes old red blood cells, called erythrocytes, from the blood supply and removes, stores and produces white blood cell lymphocytes. These stored lymphocytes produce antibodies and assist in removing microbes and other debris from the blood supply.
Characteristics of the Spleen
The spleen is a soft, dark-purple organ found in the upper-left portion of the abdomen. Located between the stomach and diaphragm underneath the rib cage, the spleen is an average of 12 cm long, 7 cm high and 4 cm thick. The weight and size of the spleen vary somewhat through life, and it can weigh from 100 to 250 g in an adult.
Features of the Spleen
The spleen is composed of two types of tissue: white pulp and red pulp. The white pulp of the spleen participates in the immune system by producing the lymphocytes. The red pulp acts as a filter and storage reservoir for the blood. Because of its function in the immune and circulatory systems, the spleen is surrounded by a multitude of blood and lymph vessels.
Considerations After Surgical Removal of the Spleen
An individual can survive without a spleen. If the spleen is severely damaged, it can be removed surgically with a procedure called a splenectomy. The majority of the functions of the spleen are taken over by the liver after a splenectomy. Once the spleen is removed, however, an individual does have an increased susceptibility to infections due to the loss of immune function for which the liver is unable to compensate.
The spleen can become enlarged as a result of infection, anemia or cancer. This enlargement is a result of an excess of trapped blood cells that can damage the spleen's function. Enlargement of the spleen is treated by addressing the underlying illness. An enlarged spleen can be detected by physician examination or via diagnostic imaging.