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Megakaryopoiesis
Thrombopoiesis is the formation of thrombocytes (blood platelets) in the bone marrow. Thrombopoietin is the main regulator of thrombopoiesis. Thrombopoietin affects most aspects of the production of platelets. This includes self-renewal and expansion of hematopoietic stem cells, stimulating the increase of megakaryocyte progenitor cells, and supporting these cells so they mature to become platelet-producing cells. The process of thrombopoiesis is caused by the breakdown of proplatelets (mature megakaryocyte membrane pseudopodial projections). During the process almost all of the membranes, organelles, granules, and soluble macromolecules in the cytoplasm are being consumed. Apoptosis also plays a role in the final stages of thrombopoiesis by letting proplatelet processes to occur from the cytoskeleton of actin. Platelets Platelets are formed by megakaryocytes and are present in the bloodstream for 5–7 days. Platelets are regulators of hemostasis and thrombosis. Platelets becom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombopoietin
Thrombopoietin (THPO) also known as megakaryocyte growth and development factor (MGDF) is a protein that in humans is encoded by the ''THPO'' gene. 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. Megakaryocytopoiesis is the cellular development process that leads to platelet production. The protein encoded by this gene is a humoral growth factor necessary for megakaryocyte proliferation and maturation, as well as for thrombopoiesis. This protein is the ligand for MLP/C_MPL, the product of myeloproliferative leukemia virus oncogene. Genetics The thrombopoietin gene is located on the long arm of chromosome 3 (q26.3-27). Abnormalities in this gene occur in some hereditary forms of thrombocytosis (high platelet count) and in some cases of leukemia. The first 155 amino acids of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1908 Platelet Development
Nineteen or 19 may refer to: * 19 (number) * One of the years 19 BC, AD 19, 1919, 2019 Films * ''19'' (film), a 2001 Japanese film * ''Nineteen'' (1987 film), a 1987 science fiction film * ''19-Nineteen'', a 2009 South Korean film * ''Diciannove'', a 2024 Italian drama film informally referred to as "Nineteen" in some sources Science * Potassium, an alkali metal * 19 Fortuna, an asteroid Music * 19 (band), a Japanese pop music duo Albums * ''19'' (Adele album), 2008 * ''19'', a 2003 album by Alsou * ''19'', a 2006 album by Evan Yo * ''19'', a 2018 album by MHD * ''19'', one half of the double album ''63/19'' by Kool A.D. * ''Number Nineteen'', a 1971 album by American jazz pianist Mal Waldron * ''XIX'' (EP), a 2019 EP by 1the9 Songs * "19" (song), a 1985 song by British musician Paul Hardcastle * "Stone in Focus", officially "#19", a composition by Aphex Twin * "Nineteen", a song from the 1992 album ''Refugee'' by Bad4Good * "Nineteen", a song from the 2001 al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombocytes
Platelets or thrombocytes () are a part of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping to form a blood clot. Platelets have no cell nucleus; they are fragments of cytoplasm from megakaryocytes which reside in bone marrow or lung tissue, and then enter the circulation. Platelets are found only in mammals, whereas in other vertebrates (e.g. birds, amphibians), thrombocytes circulate as intact mononuclear cells. One major function of platelets is to contribute to hemostasis: the process of stopping bleeding at the site where the lining of vessels (endothelium) has been interrupted. Platelets gather at the site and, unless the interruption is physically too large, they plug the hole. First, platelets attach to substances outside the interrupted endothelium: ''adhesion''. Second, they change shape, turn on receptors and secrete chemical messengers: ''activation''. Third, they connect to each other thr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone Marrow
Bone marrow is a semi-solid biological tissue, tissue found within the Spongy bone, spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It is composed of Blood cell, hematopoietic cells, marrow adipose tissue, and supportive stromal cells. In adult humans, bone marrow is primarily located in the Rib cage, ribs, vertebrae, sternum, and Pelvis, bones of the pelvis. Bone marrow comprises approximately 5% of total body mass in healthy adult humans, such that a person weighing 73 kg (161 lbs) will have around 3.7 kg (8 lbs) of bone marrow. Human marrow produces approximately 500 billion blood cells per day, which join the Circulatory system, systemic circulation via permeable vasculature sinusoids within the medullary cavity. All types of Hematopoietic cell, hematopoietic cells, including both Myeloid tissue, myeloid and Lymphocyte, lymphoid lineages, are create ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stem Cell Self-renewal
In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can change into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type of cell in a cell lineage. They are found in both embryonic and adult organisms, but they have slightly different properties in each. They are usually distinguished from progenitor cells, which cannot divide indefinitely, and precursor or blast cells, which are usually committed to differentiating into one cell type. In mammals, roughly 50 to 150 cells make up the inner cell mass during the blastocyst stage of embryonic development, around days 5–14. These have stem-cell capability. ''In vivo'', they eventually differentiate into all of the body's cell types (making them pluripotent). This process starts with the differentiation into the three germ layers – the ectoderm, mesoderm and endoderm – at the gastrulation stage. However, when they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hematopoietic Stem Cell
Hematopoietic stem cells (HSCs) are the stem cells that give rise to other blood cells. This process is called haematopoiesis. 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. In adults, haematopoiesis occurs in the red bone marrow, in the core of most bones. The red bone marrow is derived from the layer of the embryo called the mesoderm. Haematopoiesis is the process by which all mature blood cells are produced. It must balance enormous production needs (the average person produces more than 500 billion blood cells every day) with the need to regulate the number of each blood cell type in the circulation. In vertebrates, the vast majority of hematopoiesis occurs in the bone marrow and is derived from a limited number of hematopoietic stem cells that are multipotent and capable of extensive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudopodial
A pseudopod or pseudopodium (: pseudopods or pseudopodia) is a temporary arm-like projection of a eukaryotic cell membrane that is emerged in the direction of movement. Filled with cytoplasm, pseudopodia primarily consist of actin filaments and may also contain microtubules and intermediate filaments. Pseudopods are used for motility and ingestion. They are often found in amoebas. Different types of pseudopodia can be classified by their distinct appearances. Lamellipodia are broad and thin. Filopodia are slender, thread-like, and are supported largely by microfilaments. Lobopodia are bulbous and amoebic. Reticulopodia are complex structures bearing individual pseudopodia which form irregular nets. #Axopodia, Axopodia are the phagocytosis type with long, thin pseudopods supported by complex microtubule arrays enveloped with cytoplasm; they respond rapidly to physical contact. Generally, several pseudopodia arise from the surface of the body, (''polypodial'', for example, ''Amoe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombus
A thrombus ( thrombi) is a solid or semisolid aggregate from constituents of the blood (platelets, fibrin, red blood cells, white blood cells) within the circulatory system during life. A blood clot is the final product of the blood coagulation step in hemostasis in or out of the circulatory system. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of cross-linked fibrin protein. The substance making up a thrombus is sometimes called cruor. A thrombus is a healthy response to injury intended to stop and prevent further bleeding, but can be harmful in thrombosis, when a clot obstructs blood flow through a healthy blood vessel in the circulatory system. In the microcirculation consisting of the very small and smallest blood vessels the capillaries, tiny thrombi known as microclots can obstruct the flow of blood in the capillaries. This can cause a number of problems particularly affecting the pulmonary alveolus, alveoli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megakaryoblast
A megakaryoblast () is a precursor cell to a promegakaryocyte. During thrombopoiesis, the promegakaryocyte matures into the form of a megakaryocyte. From the megakaryocyte, platelets are formed. The megakaryoblast is the beginning of the thrombocytic series or platelet forming series. Megakaryoblasts typically have a large oval-shaped nucleus or a nucleus that is lobed with many nuclei. The megakaryoblast resembles the myeloblast or lymphoblast morphologically; however the megakaryoblast varies in phenotype and the structure viewed with electron microscopy. Increased amounts of megakaryoblasts in the bone marrow may indicate a disease state. An example of this is acute megakaryoblastic leukemia, which occurs when the level of megakaryoblasts in the bone marrow exceeds 20%. Development The megakaryocyte develops through the following lineage: : CFU-Meg (hematopoietic stem cell/hemocytoblast) → megakaryoblast → promegakaryocyte → megakaryocyte The megakaryoblast is deri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endomitosis
Endoreduplication (also referred to as endoreplication or endocycling) is replication of the nuclear genome in the absence of mitosis, which leads to elevated nuclear gene content and polyploidy. Endoreduplication can be understood simply as a variant form of the mitotic cell cycle (G1-S-G2-M) in which mitosis is circumvented entirely, due to modulation of cyclin-dependent kinase (CDK) activity. Examples of endoreduplication characterised in arthropod, mammalian, and plant species suggest that it is a universal developmental mechanism responsible for the differentiation and morphogenesis of cell types that fulfill an array of biological functions. While endoreduplication is often limited to specific cell types in animals, it is considerably more widespread in plants, such that polyploidy can be detected in the majority of plant tissues. Polyploidy and aneuploidy are common phenomena in cancer cells. Given that oncogenesis and endoreduplication likely involve subversion of common cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coagulation System
Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot. It results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The process of coagulation involves activation, adhesion and aggregation of platelets, as well as deposition and maturation of fibrin. Coagulation begins almost instantly after an injury to the endothelium that lines a blood vessel. Exposure of blood to the subendothelial space initiates two processes: changes in platelets, and the exposure of subendothelial Tissue factor, platelet tissue factor to coagulation factor VII, which ultimately leads to cross-linked fibrin formation. Platelets immediately form a plug at the site of injury; this is called ''primary hemostasis. Secondary hemostasis'' occurs simultaneously: additional coagulation factors beyond factor VII (#Coagulation factors, listed below) respond in a cascade to form fibrin strands, which strengthen the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
