Purkinje fibers

Purkinje fibers are located in the inner ventricular walls of the heart, just beneath the endocardium. These fibers are specialized myocardial fibers that cause an electrical stimulus or impulse that enable the heart to contract in a sophisticated and coordinated fashion. These Purkinje fibers work in tandem with the sinoatrial node (SA node) and the atrioventricular node (AV node) to positively or negatively adjust the heart rate.

From their location, the Purkinje fibers are a vital part of the cardiac cycle. During the ventricular ejection portion of the cardiac cycle, the Purkinje fibers, in accordance with the AV nodes, stimulate the ventricles of the heart. This causes them to contract and force blood to the lungs to be oxygenated, and separately, to the rest of the body to deliver oxygenated blood.