Final answer:
Before Factor X in the extrinsic coagulation pathway, Factor VII (proconvertin) is present. It forms a complex with Factor III (thromboplastin) and calcium to activate Factor X. This leads to the common pathway where a blood clot is formed through the action of several enzymes and clotting factors.
Step-by-step explanation:
The factor present in the extrinsic coagulation pathway before factor 10 is Factor VII, also known as proconvertin. The extrinsic pathway is initiated by trauma that damages tissues and leads to the release of Factor III (thromboplastin). This then binds with Factor VII and calcium ions (Ca²+) to form an enzyme complex that activates Factor X (Stuart-Prower factor), which then proceeds to the common pathway. The common pathway involves the conversion of prothrombin (factor II) to thrombin by the enzyme prothrombinase, which then turns fibrinogen (factor I) into fibrin to form a stable clot with the help of factor XIII.
Disorders affecting hemostasis include conditions such as hemophilia, which results from deficiencies or defects in certain clotting factors, leading to prolonged bleeding.