Haematopoiesis refers to the commitment and differentiation processes that lead to the formation of all blood cells from haematopoietic stem cells. In adults, haematopoiesis occurs mainly in the bone marrow (medullary), but it can also occur in other tissues such as the liver, thymus and spleen (extramedullary).The production of all types of blood cells including formation, development, and differentiation of blood cells. Prenatally, hematopoiesis occurs in the yolk sack, then in the liver, and lastly in the bone marrow.
Hematopoiesis is the production of all of the cellular components of blood and blood plasma. It occurs within the hematopoietic system, which includes organs and tissues such as the bone marrow, liver, and spleen. Simply, hematopoiesis is the process through which the body manufactures blood cells.In the human adult, the bone marrow produces all of the red blood cells, 60–70 percent of the white cells (i.e., the granulocytes), and all of the platelets. The lymphatic tissues, particularly the thymus, the spleen, and the lymph nodes, produce the lymphocytes (comprising 20–30 percent of the white cells).
Hematopoietic stem cells (HSCs) are responsible for the production of mature blood cells in bone marrow; peripheral pancytopenia is a common clinical presentation resulting from several different conditions, including hematological or extra-hematological diseases (mostly cancers) affecting the marrow function, as well