Which node delays conduction to allow ventricular filling?

Which node delays conduction to allow ventricular filling?

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

Answer: (C)

The key idea is timing in the heart’s electrical system. After the heartbeat starts at the pacemaker in the atria, the impulse travels to the ventricles through a specialized pathway. The node in the atrioventricular region acts as a gatekeeper and intentionally slows the signal. Its cells conduct more slowly than other cardiac pathways, so a deliberate delay occurs between atrial contraction and ventricular activation. That pause gives the atria time to finish contracting and filling the ventricles, increasing preload for the upcoming ventricular squeeze. Once the impulse passes through this gatekeeper, conduction speeds up through the remaining pathways—the bundle of His and the Purkinje network—so the ventricles depolarize quickly and contract in a coordinated manner. Without that AV nodal delay, the ventricles might not fill adequately before contracting. So the node that delays conduction to allow ventricular filling is the AV node.

The key idea is timing in the heart’s electrical system. After the heartbeat starts at the pacemaker in the atria, the impulse travels to the ventricles through a specialized pathway. The node in the atrioventricular region acts as a gatekeeper and intentionally slows the signal. Its cells conduct more slowly than other cardiac pathways, so a deliberate delay occurs between atrial contraction and ventricular activation. That pause gives the atria time to finish contracting and filling the ventricles, increasing preload for the upcoming ventricular squeeze.

Once the impulse passes through this gatekeeper, conduction speeds up through the remaining pathways—the bundle of His and the Purkinje network—so the ventricles depolarize quickly and contract in a coordinated manner. Without that AV nodal delay, the ventricles might not fill adequately before contracting.

So the node that delays conduction to allow ventricular filling is the AV node.