When impact or injury damaged small blood vessels at the site of injury - capillaries. From them flows the blood and spreads into the surrounding soft tissues under the skin. In a lot of blood hemoglobin, which gives it a bright red color, and a fresh bruise due to the hemoglobin has purplish-red color.
To the site of damage begin to arrive white blood cells - leukocytes. They surround the site of hemorrhage and begin to destroy blood cells, which poured out from the ruptured capillaries. The process of the breakdown of hemoglobin in red blood cells (erythrocytes) and is responsible for the sequential change the color of a bruise.
The products of destruction of hemoglobin, biliverdin (green bile pigment) and bilirubin (a yellow-red pigment of bile). In the process of destruction of hemoglobin bruise changes color from red through violet, cherry and blue to yellow-green and yellow. Then the decay products at the place of injury is removed, and the color disappears. Bilirubin is absorbed by the liver where it is converted into bile and takes part in the digestion of food.
The lower body are the bruises, the slower they heal. On the face bruise passes through the week, on TV in two weeks, and the foot can remain for months. The reason for this is that in the vessels of the legs higher the blood pressure, so they bleed stronger than, say, in his arms.
Did you know that...
Bruise science calls hemorrhage or hematoma".
By the way...
Is it possible to avoid the appearance of a bruise? You! It takes the place of injury cold (ice, soaked in cold water on a napkin). Cold compress, first, reduces pain, and second, it reduces the blood flow and constricts the vessels, and from them poured out less blood. So if the cold treatment to begin immediately, even if is a strong the injury does not appear swelling and no bruising.
And if the bruise is still formed, it is possible to accelerate its disappearance... warm! Heat promotes the resorption of the already formed hematoma, because it helps to expand the surrounding blood vessels, so that they could quickly carry away the products of decomposition. Attention! In any case, do not apply heat immediately after impact! It will not help and will only exacerbate the manifestations of hemorrhage. As warm, use a warm bath, a warm heating pad or compress. Apply to the bruise heat 3 times a day for 20 minutes.