The Probert Encyclopaedia of Medicine

SPLEEN

The spleen is a solid organ lying between the left wall of the stomach and the diaphragm, protected by the lower ribs and held in position by its capsule which is formed of peritoneum. Its very large artery comes almost directly from the aorta and its vein is one of the main tributaries of the portal system. The spleen has many functions which are known and probably others which are not known. It contains smooth muscle and is capable of contracting. It has a sponge-like structure in which the sinuses or spaces of the sponge are filled with blood. By its power of contraction it is able to expel into the circulation a large amount of this reserve blood, to meet sudden demands such as may be produced by shock or haemorrhage. In addition to this reservoir function, the spleen is the 'headquarters' of the reticulo-endothelial system. Cells of this system are found in various parts of the body, the liver, lymph glands and bone marrow. The function of the reticulo- endotheliai system with its macrophage cells is to deal with foreign particles which circulate in the blood or gain entrance to the tissues, such as bacteria, viruses and other tissue cells. Red blood cells are being continuously destroyed in the spleen. It is probable that antibodies against disease are also produced by the reticulo-endothelial system and by the masses of lymphatic tissue to be found in the spleen.
Research Spleen