Final answer:
The SA node generates more action potentials per minute than the AV node since it serves as the primary pacemaker of the heart, firing at a rate of 80-100 beats per minute compared to the AV node's 40-60 beats per minute.
Step-by-step explanation:
The number of action potentials per minute spontaneously generated by the SA node is greater than that produced by the AV node. The SA node, functioning as the heart's natural pacemaker, initiates impulses approximately 80-100 times per minute under normal conditions. In contrast, the AV node would generate a heart rate of 40-60 beats per minute if it were to act as the primary pacemaker, a situation that might occur if the SA node's function is compromised. Therefore, the inherent rate of spontaneous depolarization and action potential generation is higher in the SA node than in the AV node.
The slowing of impulse rate from the SA node to the AV node and further down the conduction system is critical for coordinated cardiac function. The electrocardiogram is a tool that helps visualize the sequential activation of the heart's chambers, with delays in the transmission of impulses allowing for proper blood flow from atria to ventricles. The synchronized function is made possible by the action potential thresholds and the 'all or none' nature of action potential propagation.