Clot Formation Review with Animations Nicole L. Draper, MD

Clot Formation Initial Steps Primary Hemostasis Adhesion Activation (2 & 3) Aggregation Robbins Basic Pathology, 9th Edition

Y Y 1-Endothelial cell injury 5- Granule release reaction- 3- vWF allows adhesion of platelet to subendothelium via GPIb 1-Endothelial cell injury Y Y 5- Granule release reaction- Secretion of ADP, serotonin & calcium cause more platelets to activate and aggregate.TxA2 synthesis. ADP 2-Release of Tissue Factor begins extrinsic pathway of coag- ulation cascade. ECM exposure. 6- Coagulation cascade produces fibrin strands That trap and enmesh the platelets and other cells into a thrombus. 4- Fibrinogen bridges form by binding GPIIb/IIIa on the platelet membrane (Initial aggregation).

Normal Secondary Hemostasis Coagulation Factors Anti-fibrinolytic System Coagulation Factors Anti-fibrinolytic System Natural Anticoagulants Fibrinolytic System Natural Anticoagulants Fibrinolytic System Anticoagulation and clot breakdown Clot formation and maintence

Secondary Hemostasis XII XI IX + VIII VII X + V Antithrombin Negatively Charged Surface (exposed ECM or activated plt) VII X + V Tissue factor from ECM Antithrombin Tissue Factor Pathway Inhibitor heparins Platelets Thrombomodulin Protein C/ Protein S II Fibrinogen XIII Stable fibrin clot