How does a platelet form a clot?

How does a platelet form a clot?

• A. They dissolve clots by releasing plasmin.
• B. They primarily release antibodies to kill pathogens.
• C. They have no role in clot formation.
• D. Aggregation to block a blood vessel and provide a surface on which fibrin strands form an organised clot, by contracting to pull the fibrin strands together to make the clot firm and permanent.

Answer: (D)

Platelets are central to stopping bleeding: they adhere to damaged vessels, then aggregate to form a plug and provide the surface on which the coagulation cascade builds a fibrin mesh. They contract to pull the fibrin strands together, tightening and stabilizing the clot so it becomes firm and permanent. This combination of forming a plug, supplying a coagulation surface, and contracting to consolidate the clot is how platelets contribute to clot formation. The other ideas aren’t how clots form: dissolving clots involves plasmin (fibrinolysis), antibodies are for immune defense, and saying platelets have no role contradicts their essential function in hemostasis.

Platelets are central to stopping bleeding: they adhere to damaged vessels, then aggregate to form a plug and provide the surface on which the coagulation cascade builds a fibrin mesh. They contract to pull the fibrin strands together, tightening and stabilizing the clot so it becomes firm and permanent. This combination of forming a plug, supplying a coagulation surface, and contracting to consolidate the clot is how platelets contribute to clot formation. The other ideas aren’t how clots form: dissolving clots involves plasmin (fibrinolysis), antibodies are for immune defense, and saying platelets have no role contradicts their essential function in hemostasis.