Why does hitting someone (or getting hit) hard causes a bruise? Why is it blue?

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Why does hitting someone (or getting hit) hard causes a bruise? Why is it blue?

In: Biology

2 Answers

Anonymous 0 Comments

The bruise is blood that has leaked, and is being broken down by the body. The colour of the bruise is dependant on how far the blood has been broken down, so it changes from pink-red to blue-purple to green to yellow-brown over time.

Blood with a lot of oxygen is red, blood with less oxygen is more bluish.

These colourings from broken down blood also affect the colour of feces and urine.

Anonymous 0 Comments

A sufficiently powerful impact will cause tissue and capilaries to break meaning you have a hematoma which is localized bleeding under the skin.

Now for some reason some blood vessels like Veins will look blue or purple through the skin, but thats because blood carrying CO2 is darker then the bright red of blood carrying O2.