It involves a series of steps that lead to the formation of a blood clot
The process starts with the injury of a blood vessel
The injury causes the release of tissue factor from the damaged tissue
Tissue factor reacts with factor VII to form an activated factor VII-tissue factor complex
This complex then activates factor X, which in turn activates prothrombin to form thrombin
Thrombin converts fibrinogen into fibrin, which forms the clot
The clot is then stabilized by the formation of cross-links between the fibrin molecules

Haemostasis is the process of stopping bleeding from a damaged blood vessel
It involves three main steps: vascular spasm, platelet plug formation, and coagulation
Vascular spasm occurs when the blood vessel constricts to reduce blood flow to the damaged area
Platelet plug formation occurs when platelets adhere to the damaged area and form a plug
Coagulation occurs when the coagulation cascade is activated, leading to the formation of a blood clot
The clot is then dissolved by the fibrinolytic system, which breaks down the clot into smaller fragments

Stage 1: Formation of prothrombinase
- Factor X is activated to form activated factor X
- Activated factor X reacts with factor V to form prothrombinase
Stage 2: Conversion of prothrombin to thrombin
- Prothrombinase reacts with prothrombin to form thrombin
Stage 3: Conversion of fibrinogen to fibrin
- Thrombin reacts with fibrinogen to form fibrin
Stage 4: Formation of cross-links
- Fibrin molecules are cross-linked to form a stable clot

Hemorrhagic disorders are conditions that affect the blood's ability to clot
Examples of hemorrhagic disorders include hemophilia A and B, and von Willebrand disease
Hemophilia A is caused by a deficiency of factor VIII
Hemophilia B is caused by a deficiency of factor IX
Von Willebrand disease is caused by a deficiency of von Willebrand factor
These disorders can be treated with replacement therapy, where the missing clotting factor is replaced with a donor-derived or recombinant version of the factor