Which coagulation pathway is initiated by tissue damage and leads to the activation of the common pathway?

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Multiple Choice

Which coagulation pathway is initiated by tissue damage and leads to the activation of the common pathway?

Explanation:
Tissue damage exposes tissue factor (thromboplastin) to the blood, which starts the extrinsic coagulation pathway. The tissue factor–VIIa complex rapidly activates factor X to Xa, kicking off the common pathway. From there, Xa (with Va) converts prothrombin to thrombin, thrombin converts fibrinogen to fibrin, and fibrin is cross‑linked to form a stable clot. The intrinsic pathway is activated by contact with damaged surfaces like collagen and serves as a slower amplifier that also converges on the common pathway. Platelet plug formation is part of primary hemostasis, not the coagulation cascade. Because tissue damage triggers tissue factor and starts the sequence toward the common pathway, the extrinsic pathway is the correct initiation route.

Tissue damage exposes tissue factor (thromboplastin) to the blood, which starts the extrinsic coagulation pathway. The tissue factor–VIIa complex rapidly activates factor X to Xa, kicking off the common pathway. From there, Xa (with Va) converts prothrombin to thrombin, thrombin converts fibrinogen to fibrin, and fibrin is cross‑linked to form a stable clot. The intrinsic pathway is activated by contact with damaged surfaces like collagen and serves as a slower amplifier that also converges on the common pathway. Platelet plug formation is part of primary hemostasis, not the coagulation cascade. Because tissue damage triggers tissue factor and starts the sequence toward the common pathway, the extrinsic pathway is the correct initiation route.

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