7/30/2023 0 Comments Exterior emulsion paint colourPlatelet activation: After binding to vWF, platelets change their shape and release mediators that lead to activation of more platelets (positive feedback).Ristocetin normally activates vWF to bind to glycoprotein Ib. Platelet adhesion : platelets bind to vWF via platelet GpIb receptor at the endothelial injury site.Binds factor VIII (and thereby prevents its degradation).Mediates platelet adhesion and aggregation.Von Willebrand factor ( vWF ): plasma protein that is synthesized by and stored in endothelial cells (in Weibel-Palade bodies ) and platelets (in α-granules ).Exposure of subendothelial collagen → circulating von Willebrand factor binds to the exposed collagen.Platelet accumulation at the vessel walls.Neural stimulation reflexes and endothelin release → transient vasoconstriction, leading to:.Definition : : processes involved in the formation of a platelet plug ( white thrombus ) following endothelial injury.Secondary hemostasis: activation of the coagulation cascade, which results in the formation of a fibrin clot ( red thrombus).Platelet hemostasis: adhesion, activation, and aggregation of platelets, which results in the formation of a platelet plug ( white thrombus).Vascular hemostasis: transient vasoconstriction and vWF activation following endothelial injury.Hemostasis involves the following mechanisms: Its final result is a thrombus (blood clot), which consists of blood cells and fibrin strands. Hemostasis is the physiological process by which a bleeding stops. Treatment may include transfusion of blood products, replacement of specific coagulation factors, or administration of adjuvant medications (e.g., tranexamic acid or desmopressin). Specialized studies are then required to determine the specific etiology so that treatment can be initiated. This typically allows the disorder to be classified as one of primary or secondary hemostasis. The diagnostic workup of a bleeding disorder begins with a detailed clinical assessment, the CBC, and a coagulation panel. Although clinical features may overlap, mucocutaneous bleeding (e.g., epistaxis, petechiae, gastrointestinal bleeding) is associated with disorders of primary hemostasis, and bleeding into potential spaces (e.g., hemarthrosis, muscular bleeding) is characteristic of disorders of secondary hemostasis. They are classified into disorders of primary hemostasis (when caused by a platelet abnormality), disorders of secondary hemostasis (when caused by defects in the extrinsic and/or intrinsic pathway of the coagulation cascade), and hyperfibrinolysis (when there is increased clot degradation). Bleeding disorders are a group of heterogeneous conditions characterized by defects in hemostasis that lead to an increased susceptibility to bleeding (also known as hemorrhagic diathesis).
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