hematopoéza

Hematopoiesis is the process by which all blood cells and platelets are formed. In adults, this vital process primarily occurs in the red bone marrow. It begins with hematopoietic stem cells, which are multipotent cells capable of differentiating into all types of blood cells, including white blood cells (leukocytes), red blood cells (erythrocytes), and platelets (thrombocytes). This differentiation is a complex, hierarchical process regulated by a variety of growth factors and cytokines.

The origin of hematopoiesis is in the yolk sac during embryonic development, with the liver and spleen taking over as the primary sites before bone marrow maturation. After birth, bone marrow becomes the main hematopoietic organ. The continuous demand for blood cells means that hematopoiesis is a lifelong process, with billions of new blood cells being produced daily.

Disruptions in hematopoiesis can lead to various hematological disorders. For example, insufficient production of red blood cells results in anemia, while a deficiency in white blood cells can compromise the immune system. Conversely, uncontrolled proliferation of certain blood cell lines can lead to leukemias and other cancers. Understanding hematopoiesis is crucial for diagnosing and treating these conditions, as well as for advancements in stem cell transplantation and regenerative medicine.