Question

Which of the following is true concerning the heart’s electrical conduction system?

• A. Action potentials pass slowly through the atrioventricular node
• B. Action potentials pass slowly through the atrioventricular bundle.
• C. Action potentials pass slowly through the Purkinje fibers.
• D. Action potentials pass slowly through the ventricle wall.

Answer 1

The correct option is A

Action potentials pass slowly through the atrioventricular node

The heart consists of two pacemakers. The primary one is the SA node. The AV node which is located in the bundle of tissues, on the border between the right chambers, i.e., the right atrium and the ventricle, is the secondary pacemaker. The SA node generates the impulse, and the AV node intensifies it and relays it throughout the heart. Whereas the SA node sets the rhythm of your pulse, the AV node sets the rhythm of your heart contractions. The AV node delays the signal on its way to the ventricle, giving the atrium time to contract first. It holds it up for about a tenth of a second. If the atrium and the ventricle contracted at the same time, the ventricles would push out their blood before they were totally full, resulting in low blood pressure and insufficient blood supply.