Cardiovascular system (comment)

In the reading, I learnt about the heart and your funtions and parts. it's interesting know that the size of heart is of your fist.



The heart have two chambers in each side (an atrium at the top and a muscular ventricle below); in the atrium is where deoxygenated blood comes in, and the ventricle is where the oxygenated blood pumped out. others parts of the heart are the valves; there are four and help to direct blood flow.


The job of the heart is circulate the blood through all the body. on a minute the heart has beaten 60 to 80 times and pumped about five liters of blood through all the body. the work of the heart is hard because never gets a rest.