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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.
The osteoclast disassembles and digests the composite of hydrated protein and mineral at a molecular level by secreting acid and a collagenase, a process known as bone resorption. This process also helps regulate the level of blood calcium. Osteoclasts are found on those surfaces of bone that are undergoing resorption.
The tibia and femur cease to be important sites of hematopoiesis by about age 25; the vertebrae, sternum, pelvis and ribs, and cranial bones continue to produce red blood cells throughout life. Up to the age of 20 years, RBCs are produced from red bone marrow of all the bones (long bones and all the flat bones).
Bone resorption is resorption of bone tissue, that is, the process by which osteoclasts break down the tissue in bones [1] and release the minerals, resulting in a transfer of calcium from bone tissue to the blood. [2] The osteoclasts are multi-nucleated cells that contain numerous mitochondria and lysosomes. These are the cells responsible for ...
Osteocalcin, also known as bone gamma-carboxyglutamic acid-containing protein (BGLAP), is a small (49-amino-acid [5]) noncollagenous protein hormone found in bone and dentin, first identified as a calcium-binding protein. [6] Because osteocalcin has gla domains, its synthesis is vitamin K2-dependent. In humans, osteocalcin is encoded by the ...
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.
Thrombopoietin is a glycoprotein hormone produced by the liver and kidney which regulates the production of platelets. It stimulates the production and differentiation of megakaryocytes, the bone marrow cells that bud off large numbers of platelets. [5] Megakaryocytopoiesis is the cellular development process that leads to platelet production.
Hemes are most commonly recognized as components of hemoglobin, the red pigment in blood, but are also found in a number of other biologically important hemoproteins such as myoglobin, cytochromes, catalases, heme peroxidase, and endothelial nitric oxide synthase. [8] [9] The word haem is derived from Greek αἷμα haima 'blood'.