Blood clotting describes the chemical change of blood from a liquid to a solid state. This is primarily for wound closure, but blood clotting can occur in other parts of the body.
What is blood clotting?
Blood clotting describes the chemical change of blood from a liquid to a solid state. When blood is in the circulation, it is liquid and remains in that state. However, various blood components are also responsible for initiating blood clotting when required. If the blood comes into contact with an open wound, the process of blood clotting starts immediately. The smaller and more harmless the wound, the faster it is closed again. Blood clotting creates a kind of net in which blood platelets (thrombocytes) get caught and form an increasingly thick, solid and drying layer through which fresh blood can no longer penetrate to the outside. A scar forms on the outside, protecting the wound from infection and giving it time to regrow new skin and close over the long term. Blood clotting is a basic function of the human body, and injuries can also occur to internal organs. However, blood clotting cannot close larger, severe wounds or life-threatening injuries, which is one of the reasons they are dangerous.
Function and task
The most important blood component for functioning blood clotting is fibrin. It is a sticky component of blood that covers the wound like a fine mesh. This happens within a very short time after the injury, because fibrin is always present in the blood. The remnants of this fibrin net can sometimes still be seen as a white border on old scars. Since fibrin is sticky and forms into a net, red platelets get caught in it on their way past the wound. The more large platelets caught in the fibrin mesh, the less blood can get out through the wound. The upper layers of clotted blood eventually dry out in the air and form a visible red wound closure. The main purpose of blood clotting is to close external and internal wounds. These are thus well protected against infection and fresh blood can no longer penetrate to the outside. While the scab of coagulated blood shields the wound from the outside, new skin very soon forms underneath. Once this has matured to the point where there is no longer a wound, it pushes off the scab from underneath and the injury is healed. If there were no blood clotting, every bleeding wound, no matter how small, would be a potentially life-threatening threat to humans, since without blood clotting the blood loss would never end. Also valuable is the protection against infection that clotted blood provides to the wound. Without this closure to the outside, there would be a very high risk of infection in any wound, as it would remain open and there would be no barrier in the form of the dried scab against dirt and pathogens trying to enter from the outside.
Diseases and ailments
Blood clotting does not work at all in some people in the form of a rare hereditary disease: it is hemophilia, which affects almost exclusively men. Every smallest wound becomes a life-threatening injury for hemophiliacs, as their blood is unable to clot. Even minor injuries continue to bleed in this way. In some wounds, even if the wound is dirty, the blood clots very quickly, even before it can be cleaned. The rapid clotting of blood traps dirt particles or pathogens in the wound and can cause infection. Injuries in dirty, non-germ-free environments cause the most common wound infections. However, if they remain superficial and are treated quickly enough, they usually do not spread. In the worst case, entrapment of dirt and germs can lead to carriage and a wide variety of diseases, from a purulent wound to a dangerous infection such as tetanus. Blood clotting can also become dangerous in the case of internal injuries. These occur in accidents, explosions and other mishaps and are sometimes not noticed at all, or at least not for a long time. Some of the blood that leaks from the internal wound clots, but the clotted particles cannot close the wound and eventually enter the bloodstream. They are called thrombi.They are dangerous because they can block smaller vessels or get caught in larger vessels and block them dangerously. This can lead to life-threatening consequences, and in the worst case, any help comes so late. If they have already formed, they must be removed from the bloodstream again with a minor intervention. Although blood clotting only attempts to close internal wounds, it fails in its purpose due to the size of such injuries and becomes a danger. That’s why even after only a minor accident, a thorough physical examination of everyone involved is important to properly treat internal injuries and eliminate the risk of thrombi. Nowadays, blood group tests are performed during blood transfusions. The reason for this is that blood coagulates even if it comes into contact with the “wrong” blood group. Although the exact chemical process is somewhat different from the usual blood clotting, clumping also occurs – which must be avoided at all costs.
