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When the body is cut, it starts to repair injuries within 24 hours, but it is between 48 and 72 hours and can be up to 21 days before the repair is fully carried out. The clotting mechanism in the blood seals the torn blood vessels, so blood plasmas cannot escape into the tissues around the injury. This is important because blood plasma is needed when moving nutrients around the bloodstream. And it is needed to transport white blood cells which fight infection around the injury, so it can continue to repair. Blood clots form when the skin breaks, and the blood clot is to stop the bleeding.

Healing happens in three different mechanisms. The first is vascular spasm. This is when the smooth muscle in the blood vessel's walls contracts as soon as the vessel is broken. This slows the bleeding while other mechanisms become active. The next mechanism is platelet plug formation. This is when the blood platelets become sticky and find a damaged vessel and form a type of plug to help close the gap in the broken blood vessels. However, this is only temporary and does not last long, but it does last long enough for the third mechanism. The third mechanism is coagulation. Once the blood comes to the surface and leaves the blood vessels, it thickens and becomes a texture similar to a gel. This is coagulation.

Blood clotting is actually when blood becomes solid. This happens when the temporary plug meets the clotting factors from the blood. This forms a web of fibres and it becomes a clot. Fibrin is a mesh found in blood, and there are a web of clotting factors, including enzymes, calcium ions, and platelets. Once this has formed, there are other cells, such as white blood cells, which fight infection and reinforce the clot, so it completely stops the bleeding. As the healing process begins, the immediate effects of the injury start to feel better. This healing process is the absorption of the swelling, removal of the debris and blood clots, known as the Pacman effect because of the way it removes waste products, growth of new blood capillaries to transport blood to the area and finally, development of initial fibrous scar tissue.

After the first 12 hours since the injury occurred and in the next four days, the cells become active and the new capillary blood vessels form. They slowly grow and establish new blood circulation in the area. If this did not happen, the injury would not heal because it must have a new supply of blood to repair the damaged tissues. As there is new circulation around the area, the blood supply can take away the dead tissue cells and the first blood clot that was formed is also cleared. The tissue that was damaged gets repaired by scar tissue, which is the fibrous scar tissue that surrounds the injury.

  • IPOSi Unit three LO3.1, 3.2, 3.3 & 3.4