Red blood cell blood circulation for about 100 to 120 days (and 80 to 90 days in a full term infant). At the end of their lifespan, they are removed from circulation. In many chronic diseases, the lifespan of the red blood cells is reduced. Erythropoiesis is the process by which new red blood cells are produced; it lasts about 7 days. Through this process red blood cells are continuously produced in the red bone marrow of large bones. (In the embryo, the liver is the main site of red blood cell production.) The production can be stimulated by the hormone erythropoietin (EPO),
Moore v. Regents of the University of California because of the potentially fatal amount of swelling in Moore's spleen. Moore signed a written consent form, authorizing the procedure. It said the hospital could "dispose of any severed tissue or member by cremation," and his spleen was removed by surgeons, who were not named as defendants, at UCLA Medical Center. Moore's blood profile returned to normal after only a few days, and further examination of his spleen led Golde to discover that Moore's blood cells were unique in that they produced a protein that stimulated the growth of white blood cells, which help to protect the body from infections.