The air starts in the lungs . The otim is in the hart it sucks in air then it go’s through the venticel then it go’s through then then it comes out of the atro. then that pumps blood and oxygen . a estimate of the hart would be a size of a pear. For a child your hart should beat 90 times and for a adult it should beat 70.
Your hart is a muscle it is the strongest muscle in your body with out your hart you wouldbe dead of no hart beeps and no oxygen.