Your heart is responsible for delivering blood to all parts of your body. It supplies oxygen and other nutrients where needed.
How Your Heart WorksYour heart is responsible for delivering blood to all parts of your body. It supplies oxygen and other nutrients where needed.Arteries carry oxygen-rich blood away from your heart to nourish your body. Veins carry oxygen-poor blood from your body to your heart.The pumpYour heart is actually two pumps that work side-by-side to move blood around your body. The right side of your heart pumps blood to your lungs to receive oxygen. The left side sends the oxygen-filled blood out to 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 valves act like one-way gates and keep blood flowing from one chamber of your heart to the other without moving backward. 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.When the atria become filled with blood, the walls of the chambers squeeze, or contract. The blood gushes through the mitral and tricuspid valves 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. Blood coming out of the left ventricle goes into the aorta and then to the arteries, where it is distributed to all parts of your body.When the contraction ends and the ventricles begin to relax, the pulmonic and the aortic valves snap shut. This action happens quickly and is what causes the familiar lub-dub rhythm called your heartbeat.The electrical systemThe rhythm of your heart is controlled by a built-in electrical system. The SA node is where your heart beat begins. It is sometimes called your heart's natural pacemaker.The SA node is located in the right atrium. It is made up of special pacemaker cells that send impulses to the AV node. The AV node is 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. Instantly, 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.Your heart, like any muscle, requires its own supply of blood. The coronary arteries carry oxygen-rich blood to your heart muscle. Veins carry blood depleted of oxygen away from the heart muscle.Things to rememberYour heart is a large pump powered by its own electrical system. Valves help keep blood flowing from chamber to chamber and from chamber to the body in an organized fashion. Your heart helps to recycle blood by sending oxygen-depleted blood to the lungs to be refreshed and oxygen-rich blood back out to the body. What we have learnedThe right side of the heart pumps blood to the body, true or false?The answer is false. The right side of the heart pumps blood to the lungs.Heart valves open and close in one direction, true or false?The answer is true. Four valves act like one-way gates, keeping blood flowing from one chamber to the other without moving backward.
Date Last Reviewed: 07/01/2021
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