Pacemaker
Imagine you're in a busy train station where everyone relies on the departure board to know when their train leaves. Just like the departure board sets the schedule for all the trains, the sinoatrial node in the right atrium sets the pace for your heartbeat. In this analogy, the departure board represents the sinoatrial node, and the trains and their schedules correspond to the heart's rhythm and heartbeat, keeping everything running smoothly and on time.
Practice Version
Pacemaker: The group of cells in the right atrium of the heart that set the pace for the heart rate, the sinoatrial node. Pacemaker. A pacemaker is a small device that helps regulate the heartbeat by sending electrical signals to the heart.