So how does the heart work?
As the heart beats, electrical signals spread, thus causing the heart to contract and pump blood. In the upper right atrium of the heart, is the sinoatrial (SA) node. This is where the electrical signals start and cause the heart to beat at 60-100 times per minute. Electrical signals move into the right and left atria, allowing for the atria to contract, pumping blood into the lower chambers, known as the ventricles. Once the signals pass the atrioventricular (AV) node, it passes the bundle of His, the ventricles begin to fill with blood, and from here the blood pumps to the lungs and the rest of the body.
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