The document summarizes the physiology of blood coagulation, including the five main components (vessels, platelets, coagulation factors, inhibitors, fibrinolysis) and how they work together in a complex system. It describes platelet activation and aggregation to form a platelet plug, followed by the coagulation cascade that forms a fibrin mesh to strengthen the clot. Fibrinolysis then acts to dissolve the clot once healing is complete to allow normal blood flow. The system is tightly regulated to balance clot formation and dissolution.

1. The Physiology of coagulation How to clot But not too much

11. Platelet Phospholipid Arachadonic acid Endoperoxidases Thromboxane A2 Calcium flux Phospholipase A2 Cyclooxygenase Thromboxane synthase Phosphodiesterase

17. Cascade effect -> amplification 2x10 8 mol Fibrin mesh 1 mol

19. Coagulation cascade XII XI IX X VIII Prothrombin (II) thrombin fibrinogen fibrin STABILISED FIBRIN V, Ca, P/L VII Intrinsic pathway Extrinsic pathway XIII APTT PT

20. X Xa II (Prothrombin) IIa (Thrombin) INITIATION VIIa TF Va VIIIa Va XIa

21. AMPLIFICATION IXa Xa-Va-II Prothrombinase Platelet IXa- VIIa-X “ tenase” TF IX VIIa THROMBIN (IIa) FIBRIN