A Wonderleaf question
Why do bruises change color?
a real page from the book
Bruises change color because trapped blood under the skin is being broken down and cleared away. Tiny vessels leak after a bump, and the red blood pigment starts changing as cleanup cells take it apart. Purple, green, and yellow are signs of that repair work moving along.
The green stage comes from biliverdin, a compound made as hemoglobin is dismantled. Yellow arrives when bilirubin forms next. Your body saves useful iron for later, sends other leftovers to the liver, and the mark fades because the mess has been cleaned up.
Wonder words
- capillaries
- hemoglobin
- biliverdin
- bilirubin
Try it out
With one finger, trace an imaginary bruise on your knee and say purple, green, yellow in the body's usual cleanup order.
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