Physical Basis for the Resting Potential

Abstract Thanks to the pioneering experiments of the Italian physician Luigi Galvani, it has long been understood that electricity plays a vital role in the functioning of the nervous system. That these electrical signals are intrinsic to animal tissues was demonstrated by the German electrophysiologist du Bois Reymond, who showed that cells have a “resting” potential, the constant voltage across the cell membrane in the absence of stimulation. This chapter describes the Nernst equation, which predicts the strength of electrical potentials that arise from ionic concentrations differences across membranes. The fundamental role of the Nernst equation for electrophysiology is presented in relationship to the parallel conductance model for the cell membrane potential. Basic equations for resting potential, including the role of the electrogenic membrane ion pump, are presented.