Figure 14-7 The action potential can be understood in terms of the cyclic relationships between factors contributing to the regenerative, depolarizing phase and the passive repolarizing phase. Positive factors (red arrows) increase the rate of depolarization in a "positive-feedback loop," with each element in the cycle favoring the subsequent one. Negative factors (gray arrows) decrease the depolarization rate by reducing or opposing the related positive factor, with K⁺ efflux eventually dominating the ionic flow and repolarizing the membrane.