Blood coagulation. Blood clotting scheme

One of the most important processes taking place in our body is the clotting of blood. Its outline will be described below (also images are provided for clarity). And since this is a complex process, it is worth considering it in detail.

How's it going?

So, the indicated process is responsible for stopping the bleeding that occurred due to damage to one or another component of the vascular system of the body.

In simple terms, we can distinguish three phases. The first one is activation. After damage to the vessel, sequential reactions begin to occur, which eventually lead to the formation of a so-called prothrombinase. This is a complex complex consisting of V and X coagulation factors. It is formed on the phospholipid surface of the platelet membranes.

The second phase is coagulation. At this stage fibrin is formed from fibrinogen - a high-molecular protein, which is the basis of thrombi, the emergence of which implies the clotting of blood. The scheme provided below, this phase clearly demonstrates.

And, finally, the third stage. It implies the formation of a fibrin clot, characterized by a dense structure. By the way, it is through washing and drying that it is possible to obtain a "material", which is then used to prepare sterile films and sponges to stop bleeding caused by rupture of small vessels during surgical operations.

About reactions

Above, the coagulation of blood was briefly described . The scheme, incidentally, was developed in the distant 1905 by a scientist-coagulologist named Paul Oscar Morawitz. And it does not lose its relevance until now.

But since 1905, in the field of understanding blood coagulation as a complex process, much has changed. Thanks to progress, of course. Scientists were able to discover dozens of new reactions and proteins that are involved in this process. And now the cascade scheme of blood coagulation is more widespread. Thanks to her, the perception and understanding of such a complex process becomes a little more understandable.

As can be seen in the image below, what is happening is literally "bricks". The internal and external system, blood and tissue, is taken into account. Each is characterized by a certain deformation, resulting from damage. In the blood system, damage is caused to vascular walls, collagen, proteases (splitting enzymes) and catecholamines (mediator molecules). In the tissue, cell damage is observed, as a result of which thromboplastin is released from them. Which is the most important stimulator of the process of coagulation (also called coagulation). It goes directly to the blood. This is his "way", but he has a defensive character. After all, thromboplastin starts the process of coagulation. After its release into the blood, the above three phases begin.

Time

So, what approximately is a blood coagulation, the scheme to understand helped. Now I would like to talk a little about time.

The whole process takes a maximum of 7 minutes. The first phase lasts from five to seven. During this time, prothrombin is formed. This substance is a complex kind of protein structure responsible for the course of the clotting process and the ability of the blood to thicken. Which is used by our body for the purpose of forming a blood clot. It clogs the damaged area, so that the bleeding stops. All this takes 5-7 minutes. The second and third stages occur much faster. For 2-5 seconds. Because these phases of blood clotting (the scheme is provided above) affect the processes that occur everywhere. And then the injury site itself.

Prothrombin, in turn, is formed in the liver. And it takes time to synthesize it. How quickly enough a sufficient amount of prothrombin is produced depends on the amount of vitamin K contained in the body. If it is not enough, the bleeding will stop difficult. And this is a serious problem. Because the lack of vitamin K indicates a violation of the synthesis of prothrombin. And this is an ailment that must be treated.

Stabilization of synthesis

Well, the general scheme of blood coagulation is clear - now you should pay a little attention to the topic of what needs to be done to restore the necessary amount of vitamin K in the body.

To begin with, eat right. The largest amount of vitamin K is found in green tea - 959 μg per 100 grams! Three times more, by the way, than in black. Because it is worth it to drink actively. Do not neglect and vegetables - spinach, cabbage, tomatoes, green peas, onions.

In the meat, vitamin K is also contained, but not in everything - only in veal, beef liver, lamb. But least of all it is in the composition of garlic, raisins, milk, apples and grapes.

However, if the situation is serious, then one variety of menus will be difficult to help. Typically, doctors strongly recommend combining their diet with the drugs they prescribed. With treatment, do not delay. It is necessary to proceed to him as soon as possible in order to normalize the mechanism of blood clotting. The treatment regimen is prescribed directly by the doctor, and he is also obliged to warn what can happen if the recommendations are disregarded. And the consequences can be liver dysfunction, thrombohemorrhagic syndrome, pernicious anemia, tumor diseases and bone marrow stem cell damage.

Schmidt's scheme

At the end of the XIX century lived a well-known physiologist and doctor of medical sciences. His name was Aleksandr Aleksandrovich Schmidt. He lived for 63 years, and most of the time he devoted research to hematology problems. But he studied the subject of blood coagulation especially carefully. He managed to establish the enzymatic nature of this process, as a result of which the scientist offered a theoretical explanation for him. Which is clearly represented by the following scheme of blood clotting.

First of all, the damaged vessel is reduced. Then, in place of the defect, a loose, primary platelet plug is formed. Then it strengthens. As a result, a red blood clot is formed (otherwise known as a blood clot). After which it is partially or completely dissolved.

In the course of this process, certain factors of blood coagulation manifest themselves. The scheme, in its detailed version, also displays them. They are denoted by Arabic numerals. And there are only 13 of them. And you need to tell about each one.

Factors

A complete blood coagulation scheme is impossible without their enumeration. Well, start with the first one.

Factor I is a colorless fibrinogen protein. Synthesized in the liver, dissolved in the plaza. Factor II - prothrombin, which was mentioned above. Its unique ability is to bind calcium ions. And it is after the cleavage of this substance that the clotting enzyme is formed.

Factor III is a complex protein, lipoprotein, tissue thromboplastin. It is commonly referred to as the transport of phospholipids, cholesterol, and triacylglycerides.

The next factor, IV, is the Ca2 + ions. Those that bind under the influence of colorless protein. They are involved in many complex processes, in addition to clotting, in the secretion of neurotransmitters, for example.

Factor V is globulin. Which is also formed in the liver. It is necessary for the binding of corticosteroids (hormonal substances) and their transportation. The factor VI existed for a certain time, but then it was decided to remove it from the classification. As scientists have found out - it includes the factor V.

But the classification did not change. Therefore, after V there is a factor VII. Includes prokonvertin, which involves the formation of tissue prothrombinase (the first phase).

Factor VIII is a protein expressed in a single chain. Known as anti-hemophilic globulin A. It is because of its lack of such rare hereditary disease as hemophilia. Factor IX is "related" to the previously mentioned. Since this is antihemophilic globulin B. Factor X is directly globulin synthesized in the liver.

And, finally, the last three points. This is the factor of Rosenthal, Hageman and stabilization of fibrin. They, in combination, affect the formation of intermolecular bonds and the normal functioning of such a process as the clotting of blood.

Schmidt's scheme includes all these factors. And it's enough to get acquainted with them fluently enough to understand how much the described process is complex and multivalued.

Anti-Injection System

This concept should also be noted. Above, the blood coagulation system has been described - the scheme also demonstrates the course of this process. But the so-called "anticoincidence" also takes place.

To begin with, I would like to note that in the course of evolution, scientists have solved two completely opposite tasks. They tried to find out - how the body can prevent the flow of blood from the damaged vessels, and at the same time keep it in a liquid state in whole? Well, the solution to the second problem was the discovery of an anticoagulant system.

It is a certain set of plasma proteins that can reduce the rate of chemical reactions. That is, inhibit.

And in this process involved antithrombin III. Its main function is to control the operation of certain factors, which includes a scheme of the blood clotting process. It is important to clarify: it does not regulate the formation of blood clots, but eliminates unnecessary enzymes that enter the bloodstream from the place where it is formed. Why is it necessary? To prevent the spread of coagulation to areas of the bloodstream that have been damaged.

Obstructive element

Talking about what the blood clotting system is (the scheme of which is presented above), one can not fail to note the substance such as heparin. It is a sulfur-containing acid glycosaminoglycan (one of the types of polysaccharides).

This is a direct anticoagulant. A substance that promotes inhibition of the activity of the coagulating system. It is heparin that prevents the formation of blood clots. How does this happen? Heparin simply reduces the activity of thrombin in the blood. However, this is a natural substance. And it's good. If you enter this anticoagulant into the body, then you can contribute to the activation of antithrombin III and lipoprotein lipase (enzymes that break down triglycerides - the main energy sources for cells).

So, heparin is often used to treat thrombotic conditions. Only one of its molecules can activate a large amount of antithrombin III. Accordingly, heparin can be considered a catalyst - since the action in this case is really similar to the effect caused by them.

There are other substances with the same action contained in the blood plasma. Take, for example, α2-macroglobulin. It promotes cleavage of the thrombus, affects the process of fibrinolysis, performs the function of transport for 2-valence ions and some proteins. It also inhibits substances involved in the process of coagulation.

Observed changes

There is one more nuance that does not demonstrate the traditional scheme of blood clotting. The physiology of our body is such that many processes imply not only chemical changes. But also physical. If we could observe the coagulation with the naked eye, we would see that the form of platelets in his process is changing. They turn into rounded cells with characteristic spike-shaped processes, which are necessary for intensive realization of aggregation - the combination of elements into a single whole.

But that is not all. From the platelets in the process of clotting different substances are released - catecholamines, serotonin, etc. Because of this, the lumen of the vessels that have been damaged is narrowing. Due to what is the functional ischemia. Blood supply in the damaged area is reduced. And, accordingly, the outflow gradually also reduces to a minimum. This allows platelets to cover the damaged areas. They, due to their spike-like processes, seem to be "attached" to the edges of the collagen fibers that are at the edges of the wound. This ends the first, the longest phase of activation. It ends with the formation of thrombin. After that, a few seconds of the coagulation and retraction phase. And the last stage is the restoration of normal blood circulation. And it is of great importance. Because a full wound healing is impossible without a good blood supply.

Good to know

Well, roughly the verbal schema of blood coagulation looks like this. However, there are a few more nuances that I would like to note with attention.

Hemophilia. It has already been mentioned above. This is a very dangerous disease. Any hemorrhage by a person suffering from them is experienced hard. The disease is hereditary, it develops due to defects in proteins involved in the process of clotting. You can find it easily enough - at the slightest cut, a person will lose a lot of blood. And spend a lot of time to stop it. And in especially severe forms, hemorrhage can begin without cause. People with hemophilia can be early disable. Since frequent hemorrhages in the muscle tissue (normal hematoma) and in the joints - this is not uncommon. Is it treated? With difficulties. Man must in the literal sense of the word refer to his body as a fragile vessel, and always be careful. If there is a bleeding - you need urgently to enter the donor's fresh blood, which contains the factor XVIII.

Typically, this disease affects men. And women act as carriers of the gene for hemophilia. It is interesting that the British Queen Victoria was such. One of her sons passed the disease. About the other two is unknown. Since then, hemophilia, by the way, is often called a royal disease.

But there are also reverse cases. This refers to the increased coagulability of blood. If it is observed, then the person also needs to be no less accurate. Increased coagulation indicates a high risk of formation of intravascular thrombi. Which clog the whole blood vessels. Often the consequence may be thrombophlebitis, accompanied by inflammation of the venous walls. But this defect is treated easier. Often, by the way, it is acquired.

It's amazing how much everything happens in the human body when he was elementary cut by a piece of paper. It is possible to tell for a long time about the features of blood, its coagulation and the processes that accompany it. But all the most interesting information, as well as demonstrating its schemes, is provided above. The rest, if desired, can be consulted individually.