The concept of coagulation comes from the Latin coagulatio . It is about the act and result of clotting : what happens when a liquid, especially blood , thickens or solidifies .
Coagulation, therefore, involves the transformation of a fluid into a pasty and dense substance. This process, when it involves blood, has important consequences for the body .
As coagulation occurs, the blood loses its liquid state until a clot is generated. This allows, for example, blood to stop flowing through a vessel that has broken.
Platelets are involved in coagulation, which are oval cells - lacking a nucleus - found in the blood of vertebrate animals. The process also develops thanks to blood proteins called fibrins . When a blood vessel is damaged, platelets first create a kind of plug to stop blood loss. This process is known as primary hemostasis . In parallel, various enzymatic reactions allow the formation of fibrin, which reinforces the plug made by platelets. This property is called secondary hemostasis .
Proteins found in the blood are known as coagulation factors and act directly in the formation of clots. There are thirteen of them, each one with a Roman numeral that identifies and orders it. Coagulation factors require activation cofactors , such as phospholipids and calcium. Regarding their function, they are essential to generate coagulation and, therefore, if they are not present the body can suffer serious bleeding problems.
There are various imbalances that affect coagulation and can cause everything from bruising to spontaneous bleeding or thrombosis (a clot that blocks a blood vessel). There are also diseases related to coagulation problems.
One of them is hemophilia , a genetic disorder linked to the X chromosome that prevents proper blood clotting. A hemophiliac patient can suffer spontaneous bleeding that is prolonged and can atrophy their joints . Three types of hemophilia can be detected: A , if coagulation factor VIII is deficient; B , if the deficit occurs in factor IX; C , with a deficit in factor XI.
Hemophilia A involves the activation of the process that transforms prothrombin into thrombin, and it is estimated that it occurs in one in every five thousand men. The incidence of hemophilia B is lower, one per hundred thousand men, and it has a variant called Leyden , even less common and with severity directly proportional to the age of the subject.
Thrombosis , on the other hand, is a clot that forms inside a blood vessel. One of the most common causes is an acute myocardial infarction , which is known in everyday speech as a heart attack or simply a heart attack . After an injury to a blood vessel, the body uses platelets and fibrin to create a clot that prevents excessive blood loss.
Of course, clot formation can also occur without injury to the vessels. When a clot breaks loose and begins to move through the body, it is called an embolism . In addition to acute myocardial infarction, other causes of thrombosis are the following:
* an alteration in coagulation factors, such as a decrease in protein S or C;
* an alteration of blood vessels, such as a traumatic rupture or arteriosclerosis.