The scenario: Sodium is found largely in the extracellular compartment with concentrations between 130-145 mM with intracellular sodium concentrations between 3.5-5mM. This chemical difference gives sodium a large concentration gradient, which when permitted (by opening of a channel or through facilitated transport) will move down its concentration gradient to enter the cell. Sodium also has a favorable electrical gradient; the cellular membrane potential sits at -70mV with the extracellular space sitting at 0 mV. Sodium being a cation, also has an electrical gradient that favors the inward movement of sodium when permitted. If we were to let sodium freely permeate across the cell membrane it would settle at its equilibrium potential where the two forces equally oppose each other. This value is +66mV, sodium would still have a favorable chemical gradient, but an unfavorable electrical gradient. At this point net inward movement down the chemical gradient would equally oppose the net outward movement down sodium's electrical gradient. Answer the questions below based on the above information:
1. if a cell has a membrane potential of -90mV and sodium is allowed to permeate across the cell membrane, which gradients would sodium be moving down?