What is the primary function of the AV node in the heart?

• A. Initiates ventricular contraction
• B. Delays impulse before ventricles contract
• C. Sends impulses to the brain
• D. Pumps blood to the lungs

Answer: (B)

The main idea is that the AV node slows the electrical signal as it passes from the atria to the ventricles. This deliberate delay gives the atria time to contract and push blood into the ventricles before the ventricles are activated to contract, ensuring optimal ventricular filling and coordinated timing in the heartbeat. The signal then moves on to the His-Purkinje system to trigger ventricular contraction.

That’s why delaying the impulse before ventricular contraction is the best description of the AV node’s primary function. The other options relate to other parts of the heart: ventricular contraction is driven by the ventricles after the AV delay, impulses reaching the brain isn’t a function of the AV node, and pumping blood to the lungs is the job of the right ventricle.