What Is the Heart?
The heart is a muscular organ that acts like a pump to send blood throughout your body all the time.
The heart is at the center of your circulatory system, which delivers blood to all areas of your body. An electrical system regulates the heart and uses electrical signals to contract the heart’s walls. When the walls contract, blood is pumped into your circulatory system.
The circulatory system is made up of a network of blood vessels, such as arteries, veins, and capillaries. The vessels in this network carry blood to and from all areas of your body. A system of inlet and outlet valves in your heart’s chambers works to ensure that blood flows in the right direction.
Your heart is vital to your health and nearly everything that goes on in your body. Without the heart’s pumping action, blood can’t circulate within your body. Blood carries the oxygen and nutrients that your organs need to function normally. Blood also carries carbon dioxide, a waste product, to your lungs to be passed out of your body and into the air. A healthy heart supplies the areas of your body with the right amount of blood at the right rate needed to function normally. If disease or injury weakens your heart, your body’s organs won’t receive enough blood to function normally.
Anatomy of the Heart
The heart is located under the ribcage in the center of the chest between the lungs. It’s shaped like an upside-down pear. The size of the heart can vary depending on age, size, or the health of the heart. A normal, healthy, adult heart most often is the size of an average clenched adult fist. Some diseases of the heart can cause it to become larger.
The heart has four chambers - right and left atria and right and left ventricles. Connected to the heart are some of the main blood vessels—arteries and veins—that make up your blood circulatory system.
The ventricle on the right side of your heart pumps blood from the heart to your lungs. When you breathe air in, oxygen passes from your lungs through blood vessels where it’s added to your blood. Carbon dioxide, a waste product, is passed from your blood through blood vessels to your lungs and is removed from your body when you breathe air out.
The atrium on the left side of your heart receives oxygen-rich blood from the lungs. The pumping action of your left ventricle sends this oxygen-rich blood through the aorta (a main artery) to the rest of your body.
A Sick Heart
The heart is made up of many parts working together to pump blood. In a healthy heart, all the parts work well so that your heart pumps blood normally. Then all parts of your body that depend on the heart to deliver blood also stay healthy.
Heart disease can disrupt a heart's normal electrical system and pumping functions. Diseases and conditions of the heart's muscle make it difficult for your heart to pump blood normally. Damaged or diseased blood vessels make the heart work harder than normal. Problems with the heart's electrical system, called arrhythmias, can make it difficult for the heart to pump blood efficiently.
Source: How the Heart Works. National Heart, Lung, and Blood Institute, National Institutes of Health, U.S. Department of Health & Human Services. January 2007