Question

what substances are involved in order for prothrombin activator to be formed in the common pathway? select all substances that are involved. thrombin calcium factor ii platelet factor 3 vitamin k factor v

Explanation:

To determine the substances involved in prothrombin activator formation in the common pathway:

• Thrombin is a product of prothrombin activation, not involved in its formation, so it's excluded.
• Calcium ($\text{Ca}^{2+}$) is essential for the coagulation cascade steps, including prothrombin activator formation.
• Factor II (prothrombin) is the substrate, not a reactant in forming the activator.
• Platelet factor 3 (PF3) provides a phospholipid surface for coagulation factors to assemble, crucial for the common pathway's prothrombin activator formation.
• Vitamin K is involved in the synthesis of coagulation factors (like Factors II, VII, IX, X) that are part of the pathway, indirectly supporting prothrombin activator formation.
• Factor V acts as a cofactor in the prothrombinase complex (prothrombin activator) formation.

So the correct substances are Calcium, Platelet factor 3, Vitamin K, and Factor V. Thrombin and Factor II are not involved in forming the prothrombin activator (Factor II is prothrombin, the substrate; thrombin is the product).

Answer:

• Calcium (selected, correct)
• Platelet factor 3 (selected, correct)
• Vitamin K (selected, correct)
• Factor V (selected, correct)
• Thrombin (unselected, incorrect)
• Factor II (unselected, incorrect)