Automatic Emergency System

The lifespan of a red blood cell is about 120 days after which they are removed by the spleen. This loss is balanced by the continuous production of new cells. Under normal conditions, 2.5 million red blood cells are generated per second, a number which can be increased if necessary. A hormone called 'erythropoietin" regulates the rate of generation. For example, as a result of heavy bleeding due to accident or nose bleeds, the loss is immediately balanced. In addition, the rate of generation is increased if the oxygen content of the air is reduced. For instance, while climbing at very high altitudes, due to the continuously declining oxygen content, the body automatically takes this action in order to make the most efficient use of the oxygen available.