The Purkinje system, or subendocardial plexus of the heart has two functions. The primary role of the fiber tracts is to carry electrical impulses to the ventricles for contraction. The second, and less important role, is to provide extra support for the myocytes (heart cells) of the ventricles. The latter function enables the ventricles or myocardial tissue to expand and contract while returning to their original shape during resting parts of the cardiac cycle.

The Purkinje system is one of the last anatomical systems to retain the name of its first describer. Purkinje gained most of his reputation for the identification of the large integrator neurons of the brain. Because the use of the term Purkinje cells can refer to either location in the brain or heart, it is best to use the phrase Purkinje fibers when discussing the conduction system of the heart.

The primary...