Blood clotting:

Blood clotting is a natural process to stop the loss of blood from body.

Mechanism of clot formation:

 Injured cell releases a substance that attracts platelets. Platelets have protein (thromboplastin) that initiate clot formation.

• Enzyme pro-thrombinase is formed by thromboplastin (protein from platelets).
• Enzyme pro-thrombinase inactivates heparin (anticoagulant).
• Enzyme pro-thrombinase converts prothrombin into thrombin.
• Thrombin converts fibrinogen into fibrin.
• Fibrin monomers polymerizes to form long-sticky fibers.
• These fibers form a fine network over the wound and cover wounded cells to form a layer called clot.
•  Clot is formed in 2-8 minutes.

Role of vitamin K in blood clotting:

It helps in synthesis of pro-thrombinase enzymes in liver.

Role of anticoagulants/anti-clotting agents:

A substance that stops the blood clotting, is anticoagulants. Heparin is one of these. It checks the clotting of blood in vessels so – that flow of blood could not get affected.

Ex – sodium & potassium oxalates (artificial), heparin (natural).

Thrombus:

Sometimes a clot is formed inside a vessel, called thrombus & its formation is called thrombosis. It blocks the blood flow & is very serious for heart or brain & even causes death.