The heart is a hollow muscular organ composed of several layers called endocardium, myocardium, and pericardium
. It has four chambers, the upper two called atria and the lower two called ventricles. Under the influence of nerve bundles, depolarizations, kinds of electrical changes, will take place and will generate contractions which enable blood
circulation. The right atrium and ventricle receive oxygen-poor blood
and send it to the lungs where gas exchange will allow it to be loaded up with oxygen. This blood then comes to the left atrium and ventricle which distribute it to all the organs that will be able to use the oxygen and restore carbon dioxide
to the veins
that will be exchanged in the lungs. The heart valves at the entry and exit of each ventricle enable oriented circulation. Many diseases
of the heart or other organs can lead to its malfunction.
Original article published by
. Translated by Jeff
Latest update on August 19, 2014 at 12:32 PM by christelle.b.