Question

multiple choice question
how is prothrombin activator formed?

when factor x combines with collagen

in the liver on a daily basis

when factor x combines with factors iii and v

when factor x combines with prostacyclin

Explanation:

To determine how prothrombin activator is formed, we analyze each option:

• "When factor X combines with collagen": Collagen is involved in platelet activation, not prothrombin activator formation. Eliminate this.
• "In the liver on a daily basis": Prothrombin (a precursor) is produced in the liver, but prothrombin activator formation is part of the coagulation cascade, not just daily liver production. Eliminate this.
• "When factor X combines with factors III and V": In the coagulation cascade, prothrombin activator is formed when factor X (activated) combines with factors III (tissue factor) and V (a cofactor), along with calcium ions and phospholipids. This matches the process.
• "When factor X combines with prostacyclin": Prostacyclin is a vasodilator and inhibitor of platelet aggregation, not involved in prothrombin activator formation. Eliminate this.

Answer:

C. When factor X combines with factors III and V (assuming the third option is labeled C; if the original options had labels like A, B, C, D, the correct one is the third option with the text "When factor X combines with factors III and V")