| Revision as of 11:10, 12 June 2004 editTopbanana (talk | contribs)81,651 editsm Fix link to bone marrow← Previous edit | Revision as of 06:51, 9 August 2004 edit undoErich gasboy (talk | contribs)Extended confirmed users2,439 edits clarify and expand. you give hemophiliacs their missing factor not platelets!Next edit → | ||
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| '''Platelets''', or '''thrombocytes''', are ]-like structures that ''stick'' together to form ] ]s. They |
'''Platelets''', or '''thrombocytes''', are ]-like structures that ''stick'' together to help form ] ]s. They activate when exposed to the ], as in a cut, or to ] exposed when the ] blood vessel lining is damaged. Once activated they release a number of ] and bind together and to the forming ] clot. | ||
| Platelets are not cells in the conventional sense, but are fragmented pieces of the ] of ]s in the ], released from the ] into the bloodstream. | |||
| ⚫ | Platelets |
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| ⚫ | Platelets are separated from ] using a ]. This is necessary because platelets do not survive the cold temperatures used to keep ]s, so they must be stored separately. People with few platelets or platelets that do not work well benefit from such donations. ] is pale ]. | ||
| A normal platelet count in a healthy person is between 150 and 400 (x 10<sup>9</sup>/] of blood). People can live independently with a count as low as 20. People can live in hospital with a count as low as 5, but spontaneous bleeding gets to be a problem. Platelets can be ] if a patient's platelet count falls too low. A low platelet count is called ], having too many platelets is called ]. | A normal platelet count in a healthy person is between 150 and 400 (x 10<sup>9</sup>/] of blood). People can live independently with a count as low as 20. People can live in hospital with a count as low as 5, but spontaneous bleeding gets to be a problem. Platelets can be ] if a patient's platelet count falls too low. A low platelet count is called ], having too many platelets is called ]. | ||
Revision as of 06:51, 9 August 2004
Platelets, or thrombocytes, are cell-like structures that stick together to help form blood clots. They activate when exposed to the air, as in a cut, or to collagen exposed when the endothelial blood vessel lining is damaged. Once activated they release a number of coagulation factors and bind together and to the forming fibrin clot.
Platelets are not cells in the conventional sense, but are fragmented pieces of the cytoplasm of megakaryocytes in the bone marrow, released from the bone marrow into the bloodstream.
Platelets are separated from donated blood using a centrifuge. This is necessary because platelets do not survive the cold temperatures used to keep red blood cells, so they must be stored separately. People with few platelets or platelets that do not work well benefit from such donations. Platelet concentrate is pale orange.
A normal platelet count in a healthy person is between 150 and 400 (x 10/L of blood). People can live independently with a count as low as 20. People can live in hospital with a count as low as 5, but spontaneous bleeding gets to be a problem. Platelets can be transfused if a patient's platelet count falls too low. A low platelet count is called thrombocytopenia, having too many platelets is called thrombocytosis.
Thrombocytopenia may be caused by the drugs that stimulate the production of antibodies against platelets. This condition is called "Drug-induced immune thrombocytopenia"
See also:
| Myeloid blood cells and plasma | |||||||||||||||||
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| Hematopoiesis |
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| Myeloid tissue |
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| Other | |||||||||||||||||