Question

Clotting of blood at injured parts is carried out by

• A. Red blood corpuscles.
• B. Lymph.
• C. White blood corpuscles.
• D. Blood platelets.

Answer 1

The correct option is D Blood platelets.

Platelets help in blood clotting. They are smaller than red or white blood cells. Blood clotting is the process by which blood changes from liquid to gel and stop bleeding. When the blood vessels get injured, platelets in blood produces prothrombin in the presence of vitamin K. The prothrombin then converts into the thrombin (active form) in the presence of thrombokinase and calcium ions. This thrombin then converts fibrinogen (inactive) into the fibrin (active). Fibrin thread then plugs the damaged part and appear like a clot.

Thus, the correct answer is option D.