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Erythropoietin (/ ɪ ˌ r ɪ θ r oʊ ˈ p ɔɪ. ɪ t ɪ n,-r ə-,-p ɔɪ ˈ ɛ t ɪ n,-ˈ iː t ɪ n /; [1] [2] [3] EPO), also known as erythropoetin, haematopoietin, or haemopoietin, is a glycoprotein cytokine secreted mainly by the kidneys in response to cellular hypoxia; it stimulates red blood cell production (erythropoiesis) in the bone marrow.
Bone marrow is a semi-solid tissue found within the spongy (also known as cancellous) portions of bones. [2] In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). [3] It is composed of hematopoietic cells, marrow adipose tissue, and supportive stromal cells.
The average lifespan of a red blood cell is approximately 120 days. During this maturation process, there is nuclear extrusion – i.e. mature erythrocytes have no nucleus. Nucleated red blood cells present in a sample of bone marrow can indicate the release of incompletely developed cells.
The heme part is synthesized in a series of steps in the mitochondria and the cytosol of immature red blood cells, while the globin protein parts are synthesized by ribosomes in the cytosol. [41] Production of Hb continues in the cell throughout its early development from the proerythroblast to the reticulocyte in the bone marrow.
The organs mainly involved in heme synthesis are the liver (in which the rate of synthesis is highly variable, depending on the systemic heme pool) and the bone marrow (in which rate of synthesis of Heme is relatively constant and depends on the production of globin chain), although every cell requires heme to function properly.
Blood cell lineage. The megakaryocyte develops through the following lineage: CFU-Meg (hematopoietic stem cell/hemocytoblast) → megakaryoblast → promegakaryocyte → megakaryocyte. Megakaryocytes are derived from hematopoietic stem cell precursor cells in the bone marrow. They are produced primarily by the liver, kidney, spleen, and bone ...
Red blood cells are circular, biconcave, disk-shaped and deformable to allow them to squeeze through narrow capillaries. They do not have a nucleus. Red blood cells are much smaller than most other human cells. RBCs are formed in the red bone marrow from hematopoietic stem cells in a process known as erythropoiesis. In adults, about 2.4 million ...
CD34 is expressed in hematopoietic progenitor cells and endothelial cells of blood vessels. Thus, it has been used as a marker for capillaries and blood vessels. One of the most densely vascular organs is the kidney, wherein networks of capillaries are intertwined with renal tubules.