Question

Which of these are necessary for initiation of blood clotting process?

• A. Prothrombinase and thrombin
• B. Tissue factor hageman factor and $C{a}^{2+}$
• C. Prothrobinase and $K^{2+}$
• D. Prothrobinase , tissue factor and $C{a}^{2+}$

Answer 1

The correct option is B Tissue factor hageman factor and $C{a}^{2+}$

There are two processes that can initiate clotting

1. A very rapid process the so-called extrinsic pathway
   
2. A slower but larger intrinsic pathway

In the extrinsic pathway- Damaged cells display a surface protein called tissue factor

In the intrinsic pathway- Factor 12 (XII) (also called the Hageman factor) circulates in the blood.

Calcium ions are required for the promotion or acceleration of blood clotting pathways

So correct option is B, Tissue factor hageman factor and $C{a}^{2+}$.