Which structure carries impulses from the atria to the ventricles?

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

Answer: (B)

The key idea is how the heart relays the electrical signal from the atria to the ventricles. After the atria generate an impulse, it reaches the atrioventricular node, which sits at the junction between the atria and ventricles. This node acts as a gatekeeper, slowing the conduction so the atria can finish contracting and the ventricles have time to fill with blood. Once the impulse passes through, it moves through the Bundle of His and then the Purkinje fibers to trigger the ventricles to contract in a coordinated way. So, the structure that carries impulses from the atria to the ventricles is the atrioventricular node.