The heart

An organ of the human body that amazes me is the heart because it beats so fast and delivers blood through all the body.

The role of the heart is to circulate blood through two pathways: the pulmonary circuit and the systemic circuit.

In the pulmonary circuit, deoxygenated blood leaves the right ventricle of the heart (the image helps to understand better the parts of it) via the pulmonary artery and travels to the lungs, then returns as oxygenated blood to the left atrium of the heart via the pulmonary vein.

In the systemic circuit, oxygenated blood leaves the body via the left ventricle to the aorta, and from there enters the arteries and capillaries where it supplies the body's tissues with oxygen. Deoxygenated blood returns via veins to the venae cavae, re-entering the heart's right atrium

It is located underneath the sternum or chest bone, and sits a little to the left. The heart is located between the lungs and lies in front of the backbone. 

the size of it is pretty close of a fist.

Now i'm going to talk about a few illnes that can alter the good function of this organ: Coronary artery disease (narrowing of the arteries), Heart attack, Abnormal heart rhythms or arrhythmias, Heart failure, Heart valve disease, Congenital heart disease, Heart muscle disease, Pericardial disease, Aorta disease, Marfan syndrome and Vascular disease.

To keep healthy the heart is recommended to eat healthy, get active, stay at a healthy weight, quit smoking and stay away from secondhand smoke, control your cholesterol and blood pressure and drink alcohol only in moderation.