Emergency Medical Technician (EMT) Intermediate Practice Exam

At which point does an electrical impulse temporarily slow down in the electrical conduction system?

1. Sinoatrial Node

2. Atrioventricular Node

3. Bundle of His

4. Purkinje Fibers

The correct answer is: Atrioventricular Node

The Atrioventricular Node (AV Node) is the correct answer because it serves a crucial function in the heart's electrical conduction system. After an impulse is generated by the Sinoatrial Node (SA Node), which serves as the natural pacemaker, the electrical signal travels to the AV Node where it experiences a temporary delay. This delay is important as it allows the atria to fully contract and empty blood into the ventricles before the ventricles contract. This timing is essential for effective heart function, promoting efficient blood flow. The delay at the AV Node prevents rapid impulses from overwhelming the ventricles and ensures coordinated contractions. In contrast, other structures in the conduction pathway, such as the Bundle of His and Purkinje Fibers, are involved in rapidly conducting electrical impulses to ensure swift ventricular contraction, rather than slowing it down.