In this episode, we talk about the heart and heart throbs-both literal and those of the televised variety. We learn how your heart's pacemaker cells use leaky membranes to generate their own action potentials, and how the resulting electricity travels through the cardiac conduction pathway from SA Node to Purkinje fibers, allowing your heart to contract. We also learn how defibrillators work to reset the rhythm of your heart. [9:33]