What are the three phases of hemostasis in order?

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Multiple Choice

What are the three phases of hemostasis in order?

Hemostasis proceeds in an orderly sequence to minimize blood loss: first the blood vessel constricts (vascular spasm), then a platelet plug forms (platelet plug formation), and finally the coagulation cascade stabilizes the plug with a fibrin mesh (coagulation). Vascular spasm starts right after injury and narrows the damaged vessel, reducing blood flow and slowing blood loss. This gives time for the next phase to happen and limits how much blood escapes. Platelet plug formation follows. Platelets stick to exposed subendothelial collagen (via von Willebrand factor), become activated, release granules, and recruit more platelets. They aggregate to form a temporary, initial seal—this is the primary hemostasis phase and it creates a localized plug at the site of injury. Coagulation then solidifies the seal. A cascade of coagulation factors leads to the generation of thrombin, which converts fibrinogen to fibrin. The fibrin strands weave through the platelet plug to form a stable, cross-linked clot, reinforcing the seal and providing enduring hemostasis. So the sequence is vascular spasm, platelet plug formation, then coagulation, making the chosen order the correct one.

Hemostasis proceeds in an orderly sequence to minimize blood loss: first the blood vessel constricts (vascular spasm), then a platelet plug forms (platelet plug formation), and finally the coagulation cascade stabilizes the plug with a fibrin mesh (coagulation).

Vascular spasm starts right after injury and narrows the damaged vessel, reducing blood flow and slowing blood loss. This gives time for the next phase to happen and limits how much blood escapes.

Platelet plug formation follows. Platelets stick to exposed subendothelial collagen (via von Willebrand factor), become activated, release granules, and recruit more platelets. They aggregate to form a temporary, initial seal—this is the primary hemostasis phase and it creates a localized plug at the site of injury.

Coagulation then solidifies the seal. A cascade of coagulation factors leads to the generation of thrombin, which converts fibrinogen to fibrin. The fibrin strands weave through the platelet plug to form a stable, cross-linked clot, reinforcing the seal and providing enduring hemostasis.

So the sequence is vascular spasm, platelet plug formation, then coagulation, making the chosen order the correct one.

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