purkinjefibre

Purkinje fibers are specialized cardiac muscle cells that form part of the electrical conduction system of the heart. They are located in the ventricles of the heart, beneath the endocardium. These fibers are responsible for rapidly conducting the electrical impulse that causes the heart chambers to contract.

The electrical impulse originates in the sinoatrial (SA) node, the heart's natural pacemaker, and travels through the atria. It then reaches the atrioventricular (AV) node, where there is a slight delay, allowing the atria to fully contract before the ventricles. From the AV node, the impulse travels down the bundle of His and then branches into the left and right bundle branches. These branches further divide into the Purkinje fibers, which spread throughout the ventricular walls.

Purkinje fibers have a larger diameter and fewer myofibrils compared to typical cardiac muscle cells. This structural adaptation allows for faster conduction of the electrical impulse. Their rapid transmission of the impulse ensures that the ventricles contract in a coordinated manner, efficiently pumping blood to the rest of the body. Disruptions in the function or conduction through the Purkinje fiber network can lead to various cardiac arrhythmias.