the spleen is an organ located in the upper left part of the abdomen under the diaphragm it is part of the lymphatic system and plays a number of important roles in the body including immune function the spleen acts as a filter removing old or damaged red blood cells as well as bacteria viruses and other foreign particles from the blood it also produces white blood cells called lymphocytes which help to fight infections and other pathogens blood storage the spleen can store a significant amount of blood which can be released into circulation when needed such as in cases of hemorrhage or shock blood cell production in certain situations such as when there is an increased demand for blood cells the spleen can produce red blood cells and other blood cells recycling of iron the spleen plays a role in recycling iron from old or damaged red blood cells which can then be used to produce new red blood cells