1) the blood is oxygenated in lungs
<p>2) the oxygenated blood from lungs and deoxygenated blood from the body is mixed in the heart and is pumped to the body and the lungs
</p>
3) the blood is deoxygenated in the body
<a href="//commons.wikimedia.org/wiki/User:Nefronus" title="User:Nefronus">Nefronus</a>
<span class="int-own-work" lang="en">Own work</span>