- An irregular, disc-shaped element in the blood that assists in blood clotting. During normal blood clotting, the platelets clump together (aggregate). Although platelets are often classed as blood cells, they are actually fragments of large bone marrow cells called megakaryocytes.
* * *An irregularly shaped disklike cytoplasmic fragment of a megakaryocyte that is shed in the marrow sinus and subsequently found in the peripheral blood, where it functions in clotting. A p. contains granules in the central part (granulomere) and, peripherally, clear protoplasm (hyalomere), but no definite nucleus; is about one-third to one-half the size of an erythrocyte; and contains no hemoglobin. SYN: Bizzozero corpuscle, blood disk, elementary bodies (2), elementary particle (1), third corpuscle, thrombocyte, thromboplastid (1), Zimmermann corpuscle. [see plate]
* * *plate·let 'plāt-lət n a minute colorless anucleate disklike body of mammalian blood that is derived from fragments of megakaryocyte cytoplasm, that is released from the bone marrow into the blood, and that assists in blood clotting by adhering to other platelets and to damaged epithelium called also blood platelet, thrombocyte
* * *n.a disc-shaped cell structure, 1-2 µm in diameter, that is present in the blood. With Romanowsky stains platelets appear as fragments of pale-blue cytoplasm with a few red granules. They have several functions, all relating to the arrest of bleeding (see blood coagulation). There are normally 150-400 x 109 platelets per litre of blood. See also thrombopoiesis.
* * *plate·let (plātґlət) a disk-shaped structure, 2 to 4 μm in diameter, found in the blood of all mammals and chiefly known for its role in blood coagulation; platelets, which are formed in the megakaryocyte and released from its cytoplasm in clusters, lack a nucleus and DNA but contain active enzymes and mitochondria. See also under factor, and see thrombocytic series, under series. Called also blood p. and thrombocyte.
Medical dictionary. 2011.
Look at other dictionaries:
platelet — platelet. См. тромбоцит. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) … Молекулярная биология и генетика. Толковый словарь.
platelet — (n.) 1895, formed in English from PLATE (Cf. plate) + dim. suffix let … Etymology dictionary
platelet — ► NOUN Physiology ▪ a small colourless disc shaped cell fragment without a nucleus, found in large numbers in blood and involved in clotting … English terms dictionary
platelet — [plāt′lit] n. [ PLATE + LET] 1. any of certain round or oval, nonnucleated disks, smaller than a red blood cell and containing no hemoglobin, found in the blood of mammals and associated with the process of blood clotting 2. THROMBOCYTE (sense 1) … English World dictionary
Platelet — Platelets, or thrombocytes, are small cytoplasmic bodies derived from cells. They circulate in the blood of mammals and are involved in hemostasis leading to the formation of blood clots. Like red blood cells, platelets have no nucleus. If the… … Wikipedia
platelet — Anucleate discoid cell (3 m m diameter) found in large numbers in blood; important for blood coagulation and for haemostasis. Platelet a granules contain lysosomal enzymes; dense granules contain ADP (a potent platelet aggregating factor), and… … Dictionary of molecular biology
platelet — UK [ˈpleɪtlət] / US noun [countable] Word forms platelet : singular platelet plural platelets biology a small piece of a cell in your blood that helps it to clot (= form a thick mass) … English dictionary
platelet — noun Date: 1895 a minute flattened body (as of ice or a mineral); especially a minute colorless disklike body of mammalian blood that assists in blood clotting by adhering to other platelets and to damaged epithelium called also blood platelet,… … New Collegiate Dictionary
platelet — /playt lit/, n. Cell Biol. a small platelike body, esp. a blood platelet. [1890 95; PLATE1 + LET] * * * or thrombocyte Small, colourless, irregular blood cell crucial in coagulation. Produced in bone marrow and stored in the spleen, platelets… … Universalium
platelet — noun A small colorless disk shaped particle found in the blood of mammals, which plays an important role in the formation of blood clots. Syn: blood platelet, thrombocyte … Wiktionary