A diffusion theory of membrane excitation.
D002118:Calcium / Q000502:physiology; D002463:Cell Membrane Permeability / Q000502:physiology*; D004594:Electrophysiology; D011188:Potassium / Q000502:physiology; D012964:Sodium / Q000502:physiology
D012964:Sodium; D011188:Potassium; D002118:Calcium