Eritropoieza

Eritropoieza is the process by which red blood cells, also known as erythrocytes, are produced. This vital process primarily occurs in the bone marrow in adults. It begins with hematopoietic stem cells, which are multipotent cells capable of differentiating into all blood cell types. These stem cells develop into more specialized progenitor cells, eventually reaching the recognizable stages of red blood cell development: proerythroblast, basophilic erythroblast, polychromatophilic erythroblast, orthochromatophilic erythroblast, reticulocyte, and finally, the mature erythrocyte.

The development of red blood cells is tightly regulated by hormones and growth factors. The most critical hormone is erythropoietin (EPO), which is produced mainly by the kidneys in response to low oxygen levels in the blood, a condition known as hypoxia. When oxygen levels drop, EPO production increases, stimulating the bone marrow to accelerate red blood cell production. Other factors, such as iron, vitamin B12, and folic acid, are also essential for effective erythropoiesis, playing crucial roles in hemoglobin synthesis and cell division. The lifespan of a red blood cell is approximately 120 days, after which they are removed from circulation by macrophages, primarily in the spleen and liver.