Platelet structure and functions

Abstract

Platelets are essential for primary hemostasis. These nucleus-free cells form as a result of polyploid megakaryocyte fragmentation. The main components of the platelet structure are membrane, cytoskeleton, granules, and tubules. Platelets are stimulated by agonists (thrombin, adenosine diphosphate, collagen, etc.) through glycoprotein membrane receptors and are regulated by intracellular signal system. The formation of platelet clot for primary arrest of bleeding is realized through platelet adhesion (adhesion to and flattening on the damaged vessel wall) and aggregation. Aggregation is paralleled by the release reaction (secretion of platelet granules and tubules). Only severe platelet abnormalities lead to serious clinical manifestations (significant hemorrhages).