Automatic regulation of cardiac activity without any external stimulus is called myogenic control. When the mammalian heart is dissected and placed in an O2-rich saline solution at 370C, the heartbeat continues without any external stimulation. The transformed muscle of the heart wall is responsible for its myogenic nature. Together they regulate the myogenic cycle.
According to Kitch and Flack, the SAN is located in the wall of the right atrium. It generates electrical signals automatically without any external stimulation. This electrical signal spreads to the wall of the right atrium. Then it reaches the left atrium from the right atrium. As a result, both atria contract simultaneously. Electrical signals then travel from the SAN to the AVN. Signal bundles from the AVN reach the Then the signal from the bundle of His reaches the Purkinje fibers of the ventricles. Impulses are transmitted to the ventricular wall via the Purkinje receptors. As a result, the ventricles contract.