Platelet

platelet: see blood clotting.

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platelet

 or thrombocyte

Small, colourless, irregular blood cell crucial in coagulation. Produced in bone marrow and stored in the spleen, platelets accumulate to block a cut in a blood vessel and provide a surface for fibrin strands to adhere to, contract to pull the strands together, and take part in the conversion sequence of coagulation factors. They also store and transport several chemicals.

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platelet

a minute cell occurring in the blood of vertebrates and involved in clotting of the blood

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platelet [′plāt·lət]

(histology)

thrombocyte

(hydrology)

A small ice crystal which, when united with other such crystals, forms a layer of floating ice, especially sea ice, and serves as seed crystals for further thickening of the ice cover.

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Platelet 

(also thrombocyte), a formed element found in the blood of vertebrate animals and man that plays an important role in blood coagulation. The platelets of vertebrate animals (except mammals) are small ovoid cells with a solid nucleus and weakly basophilic cytoplasm. In mammals, including man, platelets are anuclear bodies 2–5 µ in diameter. The platelets normally number about 250,000–350,000 per cubic mm of blood. They have granules containing serotonin and substances involved in blood coagulation, as well as mitochondria, microtubules, glycogen granules, and sometimes ribosomes. In mammals, platelets originate in the blood-forming organs when fragments of the cytoplasm of megakaryocytes separate from the megakaryocytes. The life-span of the platelets of mammals, including man, is about five to nine days.

REFERENCE

Markosian, A. A. Fiziologiia trombotsitov. Leningrad, 1970.