The smallest type of blood cell, also called a thrombocyte. Platelets play a major role in blood clotting.
(thrombocyte) n. a disc-shaped cell structure, 1–2 ?m 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; platelet activation). There are normally 150–400 × 109 platelets per litre of blood. See also thrombopoiesis.
Platelets are the small, rather uniform fragments of large bone marrow cells that aid the blood in coagulation, hemostasis, inflammation, and thrombus formation. Mild subclotting and sticking is a common early condition that can lead to thrombosis, atherosclerosis, and strokes, and can be helped by an aspirin a day, better fat digestion, and Ceanothus.... platelet aggregation
Blood platelets, or thrombocytes, are small spherical bodies in the BLOOD, which play an important part in the process of its COAGULATION. Normally, there are around 300,000 per cubic millimetre of blood.... platelets
The clumping together of platelets (small, sticky blood particles). Aggregation is the 1st stage of blood clotting and helps to plug injured vessels. Inappropriate aggregation can have adverse effects; for example, if aggregation occurs in an artery, it may result in a thrombosis.... aggregation, platelet
the process whereby platelets adhere to collagen released from endothelial cells in damaged blood vessels and aggregate to form a plug. An important metabolic pathway in platelets converts membrane phospholipids to *thromboxane A2 (TXA2), which can activate platelets. ADP, released from platelet granules, and *thrombin are other activators. The adhesive and aggregation reactions of platelets are mediated through surface membrane glycoproteins (Glp), Glp Ib and Glp IIb/IIIa. Aspirin acts as an *antiplatelet drug by irreversibly inhibiting one of the enzymes of this pathway, cyclo-oxygenase. Clopidrogel inhibits the ADP receptor on platelet membranes, and *abciximab blocks platelet aggregation by inhibiting Glp IIb/IIIa (see illustration overleaf).... platelet activation
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