NSG 368 Wk9 S1 Three Questions for Any Rhythm: The Heart's Wiring

This block has moved from the heart's pipes, to its valves and its muscle, to the pump falling behind, to the whole circulation failing. One system is left, and it runs all of them. The wiring. Every beat begins in the sinoatrial node, which is the heart's own pacemaker. Those cells depolarize on their own without being told, and we call that property automaticity. From there the impulse sweeps across the atria, pauses at the atrioventricular node, which is the single gateway between the atria and the ventricles, and then races down the bundle, its branches, and the Purkinje fibers, firing both ventricles together. That pause at the gateway is a feature, not a delay to apologize for. It lets the atria finish topping up the ventricles before the ventricles fire. A full transcript is available with this narration in the course.