Haematopoiesis (from
Greek αἷμα, "blood" and ποιεῖν "to make"; also
hematopoiesis in American English; sometimes also
haemopoiesis or
hemopoiesis) is the formation of
blood cellular components. All cellular blood components are derived from
haematopoietic stem cells. In a healthy adult person, approximately 10
11–10
12 new blood cells are produced daily in order to maintain steady state levels in the peripheral circulation.