How the Heart Works
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The heart is a muscular organ that pumps blood through the entire body. This job is important because blood carries oxygen and nutrients from the foods you eat and the air you breathe to all the cells in your body. Blood also carries waste products away from your cells.
The heart is made up of four chambers. The upper chambers are called the right atrium and left atrium, and the lower chambers are called the right ventricle and left ventricle.
The heart beats when the chambers of the heart squeeze (contract). The process starts when blood collects in the upper chambers of the heart. Once the chambers are full, an electrical signal from a group of cells called the sinoatrial node (SA node) makes the upper chambers contract. When the chambers contract, they push the blood through the tricuspid and mitral valves into the lower chambers of the heart.
Once the lower chambers have filled with blood, an electrical signal from a group of cells called the atrioventricular node (AV node) causes these chambers to contract. This pushes blood through the pulmonary and aortic valves and out of the heart.
The heart beats faster and works harder when you are active. It beats more slowly and works less hard when you are resting. Your brain sends signals to the heart to meet the oxygen needs of your body.
This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.
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