In the normal electrical conduction system of the heart, the electrical impulse normally begins at which structure?

• A. Bundle of His (AV bundle)
• B. Purkinje fibers
• C. Sinoatrial (SA) node
• D. Atrioventricular (AV) node

Answer: (C)

Verified step by step guidance

1. Understand that the heart's electrical conduction system controls the heartbeat by generating and transmitting electrical impulses.
2. Identify the primary pacemaker of the heart, which is the structure where the electrical impulse normally begins.
3. Recall that the sinoatrial (SA) node is located in the right atrium and initiates the electrical impulse that causes the atria to contract.
4. Recognize that after the SA node fires, the impulse travels to the atrioventricular (AV) node, then to the Bundle of His, and finally through the Purkinje fibers to stimulate ventricular contraction.
5. Conclude that the correct starting point of the electrical impulse in the normal conduction system is the sinoatrial (SA) node.