Final answer:
The Purkinje fibers are the final element of the heart's electrical conducting system, spreading the electrical impulse through the ventricles to trigger their contraction and blood pumping.
Step-by-step explanation:
The Purkinje fibers are the last part of the electrical conducting system of the heart. These myocardial conductive fibers are critical in distributing the electrical impulses throughout the heart to ensure that the ventricles contract properly, pumping blood efficiently throughout the body. Following the action potential initiated by the sinoatrial (SA) node, which sweeps across the atria and then to the atrioventricular (AV) node, the impulse is delayed slightly to allow the atria to finish pumping blood.
The action potential then travels through the atrioventricular bundle and the right and left bundle branches, before finally reaching the Purkinje fibers. These fibers spread the impulse to the contractile fibers of the ventricle, initiating ventricular contraction from the apex of the heart, much like squeezing a tube of toothpaste from the bottom, to pump blood into the aorta and pulmonary trunk.