Question

In the extrinsic clotting pathway, the active factor VII activates which factors?

• A. X and XI
• B. IX and XI
• C. IX and X
• D. XI and XII

Answer 1

Answer: (C)

IX and X

When there is damage to the blood vessel, the factor VII leaves the circulation and comes in contact with the tissue factor (TF), which is expressed on tissue-factor bearing cells, forming an activated TF - FVIIa. This TF - FVIIa activates factor IX and factor X. Thus, the correct answer is the option (C).