Final answer:
The Atrioventricular (AV) node is responsible for delaying the electrical impulse in the heart, ensuring the atria have time to contract and the ventricles to fill with blood.
Step-by-step explanation:
The component of the cardiac conduction system that is responsible for delaying the electrical impulse to allow time for the atria to complete contraction and the ventricles to fill is the Atrioventricular (AV) node. This delay, which is approximately 100 ms, is crucial for coordinated heart function, ensuring that the ventricles are properly filled with blood from the atria. The SA node initiates the action potential, but the impulse is only delayed when it reaches the AV node before it moves on to the atrioventricular bundle and eventually spreads to the contractile fibers of the ventricles.