The document discusses action potentials and how neurons conduct impulses. It explains that action potentials are rapid changes in membrane potential that allow neurons and muscles to communicate. Action potentials are initiated when stimuli open sodium channels, allowing sodium to rush into the cell and depolarize the membrane. Potassium channels then open, repolarizing the membrane back to its resting potential. This process allows impulses to propagate down axons via changes in membrane potential driven by ion fluxes.