How Does the Heart Work?

It's a good idea to have an understanding of the heart and how it works, so you know how to take care of it and know when something isn't right. Some basic facts about the heart are that it is roughly the size of your fist and is a muscle, it circulates the body's blood supply around 1,000 times each day, and there are about 5 quarts of blood in the human body that get circulated by the heart. All of this equals about 5,000 to 6,000 quarts of blood being pumped by the heart every day. That's a lot of blood!

The heart is situated in the chest a little more to the left than to the right. The heart's function is divided in half; the right side is the receiver of blood that needs oxygenating (venous blood), while the left side receives the blood that has been oxygenated by the lungs. The oxygenated blood is then pumped throughout the blood, delivering oxygen to the cells.

Every time the heart beats, the four chambers fill with blood. There are two chambers on each side of the heart, one above the other. The top chambers are the left and right atria, while the bottom chambers are left and right ventricles. Blood comes into the atria first, either venous (lacking oxygen) or arterial (oxygenated) blood. When the muscle of the heart contracts, the blood is forced from the atria into the ventricles. Another contractions squirts the blood into the blood vessels, and each successive contraction moves the blood further along the blood vessels.

In between the atria and ventricles are valves (the mitral and tricuspid), sort of like a one-way door. When blood goes through the atrial valve into the ventricle, the valve closes up tightly so the blood can't go back to the atrium. This allows the blood to only move in one direction. Two other valves, the aortic and pulmonary valves close up once the blood has left the ventricles.

The heart is a very strong and efficient muscle. It can pump from the heart to all of the cells in the body in about a minute. That's incredibly fast. Of course, it has to be this fast or else the cells wouldn't receive enough oxygen to keep them alive and healthy. If cells are starved of oxygen for too long, they will die.

The circulatory system as it's called, not only delivers oxygen to needy cells, but also carries away waste products like carbon dioxide, thereby cleaning the entire system. Simply put, each time a person inhales, a rush of fresh oxygen comes in, fills the lungs, it picked up by the blood cells, delivered to the heart and is then circulated to the cells, all in about a minute. This is why is the brain is deprived of oxygen for more than a few minutes, the brain cells will die and this causes permanent brain damage. So, breathe in, fill your lungs and keep that oxygenated blood circulating!