Understanding the human heart
To understand a heart abnormality, it’s important to know how a normal heart works. The heart, lungs and blood vessels make up the circulatory system. The heart is the central pump and consists of four chambers – the left atrium and ventricle and the right atrium and ventricle.
The heart also has four valves that direct the flow of blood through the heart:
- The left atrium receives oxygen-rich blood from the lungs and then empties into the left ventricle through the mitral valve.
- The left ventricle pumps oxygenated blood out to the rest of the body. Blood leaves the left ventricle through the aortic valve and enters the aorta, the largest artery in the body, flowing to organs and tissues through smaller branches of arteries.
- After oxygen in the blood is released to the tissues, blood returns to the heart through veins, the blood vessels that carry oxygen-poor blood. The blood first enters the right atrium and then enters the right ventricle through the tricuspid valve.
- The right ventricle then pumps oxygen-poor blood through the pulmonic valve and back to the lungs. The oxygen in the air we breathe binds to the blood cells that are circulating through the lungs. This oxygen-rich blood then returns to the left atrium and enters the left ventricle, where it is pumped out the body once again.