When she is ovulating this is when a woman is most fertile
"<span>Left atrium: This chamber receives oxygenated blood from the lungs and pumps it to the left ventricle. Left ventricle: The thickest of all the chambers, the left ventricle is the hardest working part of the heart as it pumps blood throughout the whole body."</span>
because Americans don't use guidlines
The endocrine system.
It releases hormones from the glands; and also controls thirst, and sleep. Which is quite interesting.