The heart is a muscle. It operates independently as you can generate and distribute an electric current through the presence in its walls nodes and conductive fiber bundles. At each electrical pulse the heart muscle contracts and then expands Alternatively, cavities, atria and ventricles empty and fill with blood through the opening and closing valves located between the holes and large arterial vessels. Thus the blood can circulate throughout the body to the rhythm of the heart pump.
The frequency and heart rate
The frequency of heartbeats in adults is between 60 and 80 beats per minute.
The electrical activity varies depending on physical activity: resting heart rate is lower than in the sport at which stress the heart rate accelerates. In children, the heart beats faster.