Question: why do you get bruises?

Rebecca Scott answered on 28 Jun 2013:

Bruises happen when you get a blow/bump to your body. The tiny blood vessels (capillaries) under the skin burst and the blood collects in a puddle in the damaged area. The bruise changes colour depending on how it is healing. So, when it is purple and swollen, it is because the swelling has cut off the oxygen supply in the area and when blood doesn’t have oxygen it is blue. When it goes greenish, this is because the body is beginning to break down the substances in the blood puddle and you are starting to heal. Then when goes that weird faded browny yellow, this is when your body is re-absorbing the blood.