This document summarizes the generation and propagation of action potentials in neurons. It discusses: - The resting membrane potential is maintained by selective permeability to potassium ions. - Action potentials are initiated by the opening of voltage-gated sodium channels, causing rapid depolarization. If the threshold is reached, an action potential fires. - After firing, potassium channels open to repolarize the membrane back to the resting potential. Some axons are myelinated to promote faster signal conduction via saltatory propagation between nodes of Ranvier.