PHDID YOU KNOW? 
Worms have 5 hearts
Worms don't have just one heart. They have FIVE! But their hearts and circulatory system aren't as complicated as ours -- maybe because their blood doesn't have to go to so many body parts.
The heart of worms functions in almost the same manner as a human heart.
The difference is that humans breathe oxygen through their mouths and noses, while worms breathe oxygen through their skin.
(s)journeyNorth