hematopoézis

Hematopoiesis is the process by which all blood cells and platelets are formed. This continuous process occurs primarily in the bone marrow of adult mammals. It originates from multipotent hematopoietic stem cells (HSCs), which have the remarkable ability to differentiate into all types of blood cells. These include red blood cells (erythrocytes) responsible for oxygen transport, white blood cells (leukocytes) that are crucial for the immune system, and platelets (thrombocytes) that play a vital role in blood clotting.

The development of blood cells is a complex and tightly regulated process. HSCs first give rise to progenitor cells, which are more specialized but still capable of proliferation. These progenitor cells then mature through various stages, acquiring the specific characteristics and functions of their final cell type. For example, myeloid progenitor cells can differentiate into granulocytes, monocytes, erythrocytes, and megakaryocytes, the precursors of platelets. Lymphoid progenitor cells, on the other hand, develop into lymphocytes, including T cells, B cells, and natural killer cells, all essential components of adaptive and innate immunity.

Hematopoiesis is influenced by a variety of growth factors and cytokines, which act as signaling molecules to control cell proliferation, differentiation, and survival. Hormones like erythropoietin, produced by the kidneys, specifically stimulate the production of red blood cells in response to low oxygen levels. This intricate system ensures a constant supply of mature blood cells to meet the body's needs and maintain overall health. Disruptions in hematopoiesis can lead to various blood disorders, such as anemia, leukemia, and thrombocytopenia.