How do electrical impulses control the regular beating of the heart?

The electrical beating of the heart is controlled by the cardiovascular control centre located within the medulla oblongata within the brain. Heart rate is controlled by the frequency of impulses being sent along the parasympathetic and sympathetic nerves to the heart. The signals are sent to the Sino-Atrial Node (SAN) which is located in the wall of the right atrium.The SAN is the primary determinant of the heart rate and is referred to as the 'pacemaker' of the heart. Once the signal is received by the SAN it releases electrical impulses which travel to the Atrioventricular node (AVN). The signals pass through a band of collagen. This acts as a barrier to the impulse transmission between the atria and ventricles.Once the AVN receives the signals the signal is then sent to the Bundle of His. The Bundle of His extends out into thinner muscles fibres called Purkyne Fibres - these are located within the apex of the heart. The Purkyne Fibres transmit the electrical activity and cause the ventricles to contract. This causes the blood to be pushed out of the left ventricle into the aorta to the rest of the body.