In the electrical conduction system of the heart, the normal pacemaker is located in which structure?

• A. Sinoatrial (SA) node in the right atrium near the opening of the superior vena cava
• B. Purkinje fiber network in the ventricular myocardium
• C. Bundle of His (atrioventricular bundle) in the interventricular septum
• D. Atrioventricular (AV) node in the interatrial septum

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the role of the heart's electrical conduction system, which controls the heartbeat by generating and transmitting electrical impulses.
2. Step 2: Identify the primary pacemaker of the heart, which is the structure that initiates the electrical impulse causing the heart to contract.
3. Step 3: Recall that the Sinoatrial (SA) node is located in the right atrium near the opening of the superior vena cava and is responsible for setting the pace of the heartbeat.
4. Step 4: Differentiate the SA node from other components such as the Atrioventricular (AV) node, Bundle of His, and Purkinje fibers, which play roles in conducting impulses but do not serve as the primary pacemaker.
5. Step 5: Conclude that the normal pacemaker of the heart is the Sinoatrial (SA) node located in the right atrium near the superior vena cava.