The human heart is one of the hardest working organs in the body, beating on average 72 times a minute (though 60-100 beats per minute is normal for an adult). As the heart beats, it provides pressure so blood can deliver oxygen and important nutrients to tissue all over your body through an extensive network of arteries.
In fact, the heart steadily pumps an average of 2,000 gallons of blood through the body each day.
The Heart’s Parts
The heart’s four chambers function as a double-sided pump. The right side of the heart takes in oxygen-depleted blood from the organs. This blood is delivered to the heart through the veins. The chambers on the left side pump oxygen-rich blood out to the body through arteries
The heart’s four chambers are:
- Right atrium: This chamber receives oxygen-depleted blood returning from the body and pumps it into the right ventricle.
- Right ventricle: The right ventricle pumps blood from the right atrium to the pulmonary artery that sends the deoxygenated blood to the lungs, where it picks up oxygen.
- Left atrium: This chamber receives oxygenated blood from the lungs and pumps it to the left ventricle.
- Left ventricle: The thickest of all the chambers, the left ventricle is the hardest working part of the heart as it pumps blood throughout the whole body.
The heart has four valves that separate each chamber so that, under normal conditions, blood cannot flow backwards. These valves are sometimes replaced if they become damaged.
The heart’s valves are:
- Tricuspid (Right AV) valve: This valve is located between the right atrium and right ventricle.
- Pulmonary valve: The pulmonary valve is the checkpoint where deoxygenated blood leaves the right ventricle on its way to the lungs.
- Mitral (Left AV) valve: The mitral valve is located between the left atrium and left ventricle.
- Aortic valve: This valve prevents blood from back-flowing into the left ventricle as it is sent out to the entire body through the aorta.
The Heart’s Crown
The heart is the king of the circulatory system. And rightly so, it has its own crown.
The word “coronary” actually means “of a crown.” This term is derived from the structure of the heart’s own blood supply: the coronary circulatory system. The arteries that fuel the heart’s muscle encircle the heart like a crown.
Coronary heart disease is caused when plaques of cholesterol collect in the arteries that feed the heart muscle. If a portion of one of these plaques ruptures, it can block one of the vessels and cause the heart muscle to begin to die because it is starved for oxygen and nutrients. This can also occur if a blood clot forms in one of the arteries of the heart.
Blood Flow Through the Heart
When working properly, deoxygenated blood coming back from organs enters the heart through the major vein, known as the vena cavae. From there, it enters the right atrium, passes through the tricuspid valve, and into the right ventricle. The blood then flows through the pulmonary valve, into the pulmonary trunk, through one of two pulmonary arteries, and out to the lungs where it receives oxygen.
On its way back from the lungs, the blood travels through four pulmonary veins, and into the left atrium at the top of the heart. After going through the mitral valve, the blood is in the left ventricle, the heart’s powerhouse. The blood quickly travels out through the aortic valve and out of the ascending aorta where it travels through a maze of arteries to get to every cell in the body.