Blood clotting: how it works

In short: Blood clotting is a vital protective mechanism that prevents excessive blood loss from injuries by sealing the wound with a clot. The process relies on a complex interplay of platelets and clotting factors.

In more detail: The body must regulate blood clotting very precisely, since too little clotting leads to bleeding while too much can cause dangerous thrombosis.

Note: Not a substitute for medical advice.

In detail

• Vasoconstriction: Immediately after an injury, the affected blood vessels narrow to reduce blood flow to the wound.
• Platelet aggregation: Platelets stick to the damaged vessel wall and clump together, forming an initial, loose plug.
• Coagulation cascade: A chain of over a dozen clotting factors activates in a specific order and eventually leads to the formation of fibrin.
• Fibrin mesh: Fibrin strands reinforce the platelet plug into a stable clot that reliably seals the wound.
• Vitamin K: This vitamin is essential for the liver’s production of several important clotting factors.
• Fibrinolysis: Once the wound has healed, the body deliberately breaks down the clot again to reopen the blood vessel.
• Clotting disorders: Conditions like haemophilia or taking blood thinners significantly affect normal clotting function (blut-zusammensetzung-und-aufgaben, wundheilung-phasen-und-ablauf).