The equilibrium membrane potential for the case of multiple ions will depend not only on the concentrations of the ions within and outside the cell, but also on the permeability of the cell membrane to each ion Pi. Consider a situation in which only the Na+ and K+ ions are important. For a cell at rest, PNa+ is much smaller than PK+. Typically PNa+ is about 0.01 PK+. Calculate the equilibrium membrane potential for a cell under these conditions. During the depolarization phase of an action potential, the sodium ion permeability increases dramatically due to the opening of the voltage-gated sodium ion channels. Under these conditions, PK+ is about 0.5 PNa. Under these conditions, recalculate the value of the equilibrium membrane potential.