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Diagram showing the development of different blood cells from haematopoietic stem cell to mature cells. Haematopoiesis (/ h ɪ ˌ m æ t ə p ɔɪ ˈ iː s ɪ s, ˌ h iː m ə t oʊ-, ˌ h ɛ m ə-/; [1] [2] from Ancient Greek αἷμα (haîma) 'blood' and ποιεῖν (poieîn) 'to make'; also hematopoiesis in American English, sometimes h(a)emopoiesis) is the formation of blood cellular ...
Haematopoiesis (from Greek αἷμα, "blood" and ποιεῖν "to make"; also hematopoiesis in American English; sometimes also haemopoiesis or hemopoiesis) is the formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells. [3]
Hematopoietic stem cells (HSCs) are the stem cells [1] that give rise to other blood cells.This process is called haematopoiesis. [2] In vertebrates, the first definitive HSCs arise from the ventral endothelial wall of the embryonic aorta within the (midgestational) aorta-gonad-mesonephros region, through a process known as endothelial-to-hematopoietic transition.
Bone marrow is a center of a variety of immune activities: i) hematopoiesis, ii) osteogenesis, iii) immune responses, iv) distinction between self and non-self antigens, v) central immune regulatory function, vi) storage of memory cells, vii) immune surveillance of the central nervous system, viii) adaptation to energy crisis, ix) provision of ...
These hematopoietic stem cells are further closely associated with endothelial cells throughout human life. Later, they migrate to the fetal liver where the majority of physiologic EMH (extra-medullary hematopoiesis) takes place. They can also migrate to the spleen and lymph nodes where hematopoiesis can occur, but to a lesser degree.
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).
Clonal hematopoiesis may occur in people who are completely healthy but has also been found in people with hematologic diseases. [ 1 ] [ 9 ] [ 10 ] The clonal population may vary in size depending on the person, where it can be less than 2% of the blood or, at the other end, can sometimes grow close to 100%.
There are 2 types of hematopoiesis that occur in humans: Primitive hematopoiesis – blood stem cells differentiate into only a few specialized blood lineages (typically isolated to early fetal development). Definitive hematopoiesis – multipotent HSCs appear (occurs through the majority of human lifetime).