What conducts impulses from the AV node toward the ventricles and toward the apex?

• A. Atrioventricular bundle
• B. Bundle branches
• C. Purkinje fibers
• D. SA node

Answer: (A)

The main pathway transmitting impulses from the AV node down into the ventricles and toward the apex is the atrioventricular bundle (bundle of His). This bundle carries the signal from the AV node into the lower conducting system and into the interventricular septum, where it splits into the right and left bundle branches that race toward the apex. From there, the Purkinje fibers quickly distribute the impulse through the ventricular myocardium to produce coordinated contraction. The SA node sets the pace in the atria, not the conduit to the ventricles, and while Purkinje fibers play a crucial role in distribution within the ventricles, the initial highway from the AV node to the ventricles is the AV bundle.