Platelets: Structure, Function, and Their Fundamental Contribution to Hemostasis and Pathologic Thrombosis

Abstract

Platelets play a critical role in normal hemostasis by stopping blood loss after vascular injury. By adhering to sites of injury, recruiting other platelets and blood cells to the developing clot, and activating the plasma coagulation cascade, primary hemostasis is effected. In synchrony with the end products of the coagulation cascade, predominantly crosslinked fibrin, a more stable clot quickly forms. However, by these same mechanisms, platelets also contribute directly to pathologic vascular thrombosis. In the ongoing search for means to prevent or temper vascular thrombosis while preserving physiologic hemostasis, a better understanding of platelet structure and function is of paramount importance. In this chapter we provide a composite overview of platelets, focusing on their structure, function, and fundamental contribution to normal hemostasis and pathologic thrombosis.