Which statement about the AV node is true?

• A. It is a small group of cells in the low right atrium near the tricuspid valve and slows conduction to allow time for the atria to contract and empty blood into the ventricles.
• B. It is located in the left atrium near the mitral valve and it accelerates conduction to the ventricles.
• C. It has a rate of 60 to 100 times/min.
• D. It cannot function as a pacemaker.

Answer: (A)

The AV node’s job is to slow the electrical impulse as it passes from the atria to the ventricles, creating a brief delay that lets the atria finish contracting and push blood into the ventricles before they contract. It sits in the lower part of the right atrium near the tricuspid valve, so this location naturally supports that delay. This pause is essential for coordinated heart timing and optimal ventricular filling.

The other statements don’t fit this anatomy and physiology. It isn’t located in the left atrium near the mitral valve, and it does not accelerate conduction. Its intrinsic pacing rate is slower than the SA node, typically around 40–60 beats per minute, though it can act as a secondary pacemaker if the SA node fails. So saying it cannot function as a pacemaker is incorrect.