Question

When blood is taken out, anticoagulants like oxalate/ sodium citrate can be added to prevent blood clotting. These anticoagulants work by
A)Preventing action of blood clotting factor III
B)Preventing action of heparin
C)Preventing action of blood clotting factor IV
D)Promoting the action of heparin

Answer 1

Hint: Coagulation is a process by which blood changes from liquid to gel by forming a blood clot. Blood clot is a clump like structure formed to prevent the loss of blood due to injury. The platelets are responsible for forming a clot.

Complete answer:
To solve this question, we must know about the process of coagulation and the action of anticoagulants.
Anticoagulants are the chemical substances that reduce the blood coagulation by prolonging the clotting time. Anticoagulants like oxalate or sodium citrate are commonly used.

Mechanism of Action- The sodium citrate is essential for blood clotting. The calcium is a clotting factor (IV) which is the most important clotting factor.The calcium is precipitated or bound as a non-ionised form. Thus, inhibiting the action of clotting factor.

Blood clotting factor III is called thromboplastin. It catalyses the formation of thrombin from prothrombin.

The heparin is an anticoagulant. It is found naturally in blood so that the blood can flow freely in the body. It inhibits the clotting factors by binding with the antithrombin.

Hence, the correct answer is option (C)

Note: Calcium is an important clotting factor which is essential for completing the process of clot formation. Its major role is to activate the platelets, and also activate several other clotting factors like factor 13. It also regulates the process of coagulation cascade.