Understanding a healthy heart is ultimately the very first step to preventing heart disease. By learning how your heart works, and how damage affects your heart, you are taking the first step toward a healthy heart.

It goes without saying that the heart is a remarkable organ. It beats 100,000 times, and pumps about 2,000 gallons of blood, each day. At rest, the heart muscles are still working twice as hard as your leg muscles during a full-out sprint. Your heart is responsible for pumping the blood that circulates throughout your entire body – a hefty task. It is this blood that carries oxygen and nutrients to your body's cells. It also removes waste, especially carbon dioxide, from these cells.   A fully functioning and healthy heart sustains your life at every level by providing the oxygen and eliminating the waste from each of your body's tissues and organs.

How the Heart Works
As the heart beats, it pumps blood through the circulatory system, which is a vast system of blood vessels reaching to tissues and organs throughout the body. There are three different kinds of blood vessels: the arteries, the capillaries and the veins. The arteries are blood vessels that leave the heart through the aorta to carry oxygen and nutrients to the body. The veins are the blood vessels that carry carbon-dioxide-rich blood back to the heart. The capillaries are very thin blood vessels that connect the arteries and veins and through which oxygen, carbon dioxide and other nutrients travel to the body's cells.

The heart is your body's pump.
The heart is a fist-sized pump made of muscle. Its muscular walls contract to pump blood to the arteries. The pumping within the heart works through a system of chambers and passageways.

Your heart is compartmentalized.
The heart is divided into four chambers. There are two chambers on each side of the septum, a divider that separates the left side from the right side. The right and left sides of the heart are divided into two top chambers and two bottom chambers. The top chambers, called the atria, receive blood from the veins. The bottom chambers, called ventricles, pump blood into the arteries.  

Valves play a key role.
Each side of the heart has two valves that allow blood to pass through the heart. These valves play a key role in that they prevent blood from flowing in the wrong direction.

The lungs and the heart work together.
Blood flows continuously through the heart by entering the right side through two large veins, the inferior and superior vena cava, and emptying oxygen-poor blood into the right atrium. From the right atrium, the blood travels through the tricuspid valve into the right ventricle. The ventricle contracts, and oxygen-poor blood leaves the right side of the heart through the pulmonic valve, where it enters the pulmonary arteries. The pulmonary arteries take blood into the lungs, where it is oxygenated. From there, oxygenated blood travels back to the left side of the heart through the pulmonary veins, at which time it enters the left atrium. From the left atrium, blood flows through the mitral valve into the left ventricle. The left ventricle is the largest and strongest part of the heart and is often described as the main pumping chamber, because it pumps blood out of the heart, through the aortic valve, into the aorta. From the aorta blood is then dispersed to feed your body.

Your heart needs blood too.
Remember that the heart is an organ too. It also needs a supply of oxygen and blood. That's what the coronary arteries are for. The right coronary artery and the left main coronary artery and their branches supply every part of the heart with the oxygen-rich blood it needs to continue to function.  

The heart is a complicated muscle, and the above is just a brief synopsis of how it functions.   When you realize how hard the heart works just to pump once, let alone 100,000 times a day, you can see how important it is to take care of your heart. Heart disease, in any form, happens when one of these important functions is impaired or damaged. When the heart has to work harder to compensate for damage, your whole body suffers. Taking good care of your heart helps your entire body, at every level.

Basic Heart Vocabulary

Aorta – The largest artery in the body, which carries oxygenated blood from the heart to the rest of the body.

Arteries – The blood vessels that carry blood away from the heart.

Atria – The upper chambers of the heart. The right atrium receives poorly-oxygenated blood from the body. The left atrium receives well-oxygenated blood from the lungs.

Capillaries – The web-like network of blood vessels between the veins and the arteries that pass oxygen to the body's cells.

Septum – The muscular wall that divides the two chambers of the heart.

Valve – A flap in the heart that ensures one-way flow of blood.

Ventricles – The lower chambers of the heart. The right ventricle pumps blood to the lungs. The left ventricle pumps oxygenated blood through the aorta and on to the rest of the body.

Click below to read about related topics.

Introduction
A Healthy Heart
Cardiovascular Disease
Understanding the Risks
Interpreting the Numbers
Steps You Can Take Today
On the Road to a Healthy Heart