Coagulation

A coagulation, also known as clot, is a semi-solid substance blood forms on purpose to stop a leak. Blood does this especially when it is in air. When a person bleeds, the blood turns into a clot at the site of injury so no more blood can escape.

A blood clot called a thrombus is one example of a blood clot. 

The clotting process is called coagulation. 

If a person gets a cut on their body, they will bleed. To stop the bleeding, the human body first tells the liver to produce chemicals that will help the clot to form, the message coming from the brain. When the chemicals released by the liver arrive at the injury through the circulation, coagulation begins. At the same time, the brain also lessens the blood flow near the site of injury (by tightening the veins and arteries in that area), so that not as much blood is lost. 

There is a limit to how quickly a clot can form. If the cut is very deep and the person is bleeding too much, a clot may not be able to form and a lot of blood may be lost. Losing too much blood too quickly can be fatal. In medical emergencies where the blood circulation needs to be temporarily stopped (like to prevent death by hypovolaemia) they might use a Tourniquet on the limb if they can. 

 The details 

Coagulation begins almost instantly after an injury to the blood vessel has damaged the endothelium lining the vessel. When blood is exposed to proteins such as tissue factor it starts changes to blood platelets and the plasma protein fibrinogen, which is a clotting factor. Platelets immediately form a plug at the site of injury. Proteins in the blood plasma, called coagulation factors or clotting factors, respond in a complex cascade to form fibrin strands. These strengthen the platelet plug.

Coagulation is highly conserved throughout biology; that means its genetics is almost the same in all species of mammal. In all mammals, coagulation involves both a cellular (platelet) and a protein (coagulation factor) component. The system in humans has been the most extensively researched and is the best understood.

 Fibrin 
Fibrin is a white insoluble fibrous protein formed by the action of thrombin on fibrinogen when blood clots. it forms a network that traps red cells and platelets.

 Vitamin K 
Vitamin K is an essential factor in blood clotting. Then, vitamin K is oxidized. Another enzyme, Vitamin K epoxide reductase, (VKORC) reduces vitamin K back to its active form. This reactivation is important as a target of anticoagulant drug warfarin. Vitamin K can be found in green vegetables, such as spinach, lettuce, broccoli or cabbage.

 Related pages 

 Haemophilia
 Heart

 References 

Category:Blood