Definition
- Platelets are small, anucleated, granular, spherical or oval subcellular elements, 1.5 to 3.0 µm in diameter, with highly developed cytoskeletal and canalicular systems specialized for hemostasis.
Cell Membrane
- The platelet membrane is a trilaminar unit: a phospholipid bilayer embedding cholesterol, glycolipids and glycoproteins, covered by an exterior glycocalyx coat.
Platelet structure
- Membrane glycoprotein receptors bind collagen, ADP, von Willebrand factor and fibrinogen; GPIIb/IIIa specifically mediates platelet adhesion and aggregation.
- Membrane glycoproteins also prevent platelet adherence to the normal, uninjured vascular endothelium.