Hematopoiesis is the process by which blood cells are formed in the body. It primarily occurs in the bone marrow, where stem cells differentiate into various types of blood cells, including red blood cells, white blood cells, and platelets. This process is essential for maintaining healthy blood levels and supporting the immune system. The regulation of hematopoiesis involves various growth factors and hormones, such as erythropoietin for red blood cell production. The body continuously produces new blood cells to replace those that are old or damaged, ensuring proper function and oxygen transport throughout the body.