Which structure transmits the impulse from the AV node to the ventricles?

• A. Purkinje fibers
• B. SA node
• C. Bundle of His
• D. Bundle of branches

Answer: (C)

The impulse from the AV node is transmitted through the bundle of His, the AV bundle, which sits in the upper part of the interventricular septum and then splits into the right and left bundle branches. This bundle of His provides the direct link from the AV node to the ventricles, so it is the essential conduit that carries the signal onward to the ventricular conduction system. From there, the impulse travels through the Purkinje fibers to excite the ventricular myocardium.

The Purkinje fibers are the final distribution network within the ventricles, not the primary bridge from the AV node. The SA node is the natural pacemaker in the atria and initiates the impulse, but it’s upstream of the AV node. The bundle of branches are the pathways after the bundle of His that continue conduction into the ventricles, rather than the sole connector from the AV node to the ventricular tissue.