Blood Coagulation

Abstract

This chapter describes the composition of the vascular system and an overview of how common bleeding problems arise (Sect. 1). A description follows of how blood vessel injury activates platelets and fibrinogen to plug the clot and attract and activate the blood clotting proteins (Sect. 2), how these proteins activate thrombin by extrinsic, intrinsic, and common pathways and how defects in the thrombin activators lead to different forms of hemophilia (Sect. 3). The mechanisms of how a fibrin clot is made and removed for tissue repair (Sect. 4) and prevented from occurring in undamaged (healthy) blood vessels are described (Sect. 5). The chapter concludes with a list of drugs that affect coagulation and of laboratory tests to determine the condition of the clotting system (Sect. 6).