Where are Purkinje fibers primarily located?

Purkinje fibers are specialized conductive fibers located primarily in the ventricles of the heart, playing a crucial role in the heart's electrical conduction system. They arise from the bundle branches of the atrioventricular (AV) bundle, also known as the bundle of His, and extend throughout the ventricular myocardium. Their primary function is to rapidly conduct electrical impulses to the myocardial cells of the ventricles, ensuring coordinated and efficient contraction of the ventricles, which is vital for proper blood circulation.

Understanding the function and positioning of Purkinje fibers is essential for comprehending how the heart maintains its rhythm and responds to electrical stimuli. While the other structures listed in the options (such as the AV node, AV bundle, and AV junction) are key components of the heart's conduction system, they do not serve as the primary locations for Purkinje fibers, which are specifically found in the ventricular walls.