The Pacemaker of the Heart

The Pacemaker of the Heart

The pacemaker of the heart, a tiny area of specialized nervous tissue in the right atrium, sets the heart beating about seventy times a minute. Without it the heart would beat only forty times per minute, which is too slow for the body's needs. The pacemaker, or sinuatrial node, regularly sends out nerve impulses which spread through the two atria, causing them to contract. From the atrioventricular node the contraction spreads down special conducting tissue, the bundle of His, causing the ventricles to contract and pump blood out of the heart.