The heart’s architecture is vital to its performance. It has a left side and a right side, separated by the thin muscular septum. Both sides have an upper and lower chamber, all four of which play their own role in blood transportation.
First, deoxygenated blood flows into the right side of the heart, entering the atrium. Drawn down by gravity, the blood flows through the valve and enters the right-hand ventricle. At this point, the heart beats. This beat forces the deoxygenated blood up the pulmonary artery, toward the lungs.
After the red blood cells have become loaded with oxygen from the lungs, the oxygen-rich blood enters the heart through the left-hand atrium and is then forced into the left ventricle. This ventricle produces intensely high pressure. From this pressure, the oxygenated blood is forced through the aorta artery, to the rest of the body.
Throughout this process, there are three valves that prevent the blood flowing backward. These valves allow the varying pressure differences. Surrounding the four main chambers of the heart, there are three layers of tissue. First is Endocardium, a thin layer of muscle cells that line the chambers themselves. Next is a thick middle layer, made up of powerful interwoven muscle fibers. Finally, the pericardium surrounds the organ, forming a thin, protective outer lining.