Question
Proaccelerin is ‑
| A. |
Factor II |
| B. |
Factor V |
| C. |
Factor VII |
| D. |
Factor X |
|
Correct Answer » B Explanation |
 |
Detailed Explanation:
Anatomical Role:
– Proaccelerin is the traditional name for Factor V, a coagulation factor involved in the clotting cascade.
Clinical Reasoning for the Correct Answer:
– Factor V is also known as Labile Factor, which supports its identification as proaccelerin.
– Factor V acts as a cofactor for the conversion of prothrombin to thrombin in the prothrombinase complex with Factor Xa.
– It is synthesized in the liver and circulates in the plasma as a single-chain glycoprotein.
– Its deficiency leads to parahemophilia (Factor V deficiency bleeding disorder), reinforcing its identity as proaccelerin.
Why Option A is Incorrect:
– Factor II is prothrombin, not proaccelerin. It is a precursor to thrombin and is distinct from Factor V.
Why Option C is Incorrect:
– Factor VII is called Stable Factor, unrelated to proaccelerin. It initiates the extrinsic coagulation pathway with tissue factor (Factor III).
Why Option D is Incorrect:
– Factor X is the Stuart-Prower Factor, acts in the common pathway but is not proaccelerin.