Purkinje Fibers - Histology

Histology

Purkinje fibers are a unique end-organ cardiac extension of the autonomic nervous system. Further histologic examination reveals that these fibers are split into left and right trees as well as atrial and ventricular contributions. The electrical origin of atrial Purkinje fibers arrives from the sinoatrial node. The following electrical origin of the ventricular Purkinje fibers arrives from the Atrioventricular Node.

Given no aberrant channels, the atrial and ventricular Purkinje trees are distinctly shielded from each other by collagen or the cardiac skeleton.

The Purkinje fibers are uniquely dedicated to sympathetic electrical depolarization of the right and left atria and ventricles. The Purkinje fibers are further specialized to rapidly conduct impulses (numerous fast voltage-gated sodium channels and mitochondria, fewer myofibrils than the surrounding muscle tissue). Purkinje fibers take up stain differently from the surrounding muscle cells, and, on a slide, they often appear lighter and larger than their neighbors. They are binucleated.