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Your heart is responsible for delivering blood to all parts of your body. It supplies oxygen and other nutrients where needed. Veins carry oxygen-poor blood from your body to your heart. Arteries carry oxygen-rich blood away from your heart to nourish your body.

Your heart is actually two pumps side-by-side that work together to distribute blood throughout your body. The right side of your heart pumps blood on a short trip to your lungs to receive oxygen while the left side delivers the oxygen-enriched blood throughout your body.

Each side of your heart has two compartments or “chambers.” The top chambers are called the atria and the bottom ones are called the ventricles. Four special valves keep blood flowing from one chamber of your heart to the other without moving backwards, like one-way gates. These are the tricuspid valve, the pulmonic valve, the mitral valve and the aortic valve. The tricuspid valve and mitral valve are located between the atria and the ventricles. The pulmonic valve and aortic valve are located between the ventricles and the major blood vessels leaving your heart.

After the atria fill with blood, their walls contract. The blood squeezes through the mitral and tricuspid valves, gushing into the ventricles. Once the ventricles are filled, the valves close. The muscles in the ventricles then contract, which forces open the pulmonic valve and the aortic valve. Blood coming out of the right ventricle goes to your lungs to replenish itself with more oxygen. Blood coming out of the left ventricle supplies oxygen to all parts of your body. When the contraction ends and the ventricles begin to relax, the pulmonic and aortic valves snap shut.

The rhythm of your heart is very organized and controlled by a built-in electrical system. The SA node, your heart’s own natural pacemaker, is where your heartbeat begins. Located in the right atrium, these special “pacemaker” cells send impulses to the AV node. The AV node is located in the center of your heart and acts as a relay between the atria and the ventricles. When the SA node “fires”, the atria contract and an impulse passes to the AV node. Once the impulse passes through the AV node, it travels down through nerve fibers to the bottom of the ventricles, causing the ventricles to contract and squeeze blood out of your heart. These actions produce in a wave-like pumping pattern.

Your heart, like any muscle, requires its own supply of blood. Coronary arteries, veins and their branches supply blood to your heart and remove blood from it.

Your heart may not function well if there are any problems with the valves, the electrical system or its own blood supply. Contact your healthcare provider if you have questions or concerns about how your heart is working.

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