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.