And when we have our right potential, this is the amount of sodium ions on the inside, and this is the amount of sodium ions on the outside. Now notice what happens. Our sodium ions tend to move from the outside to the inside, and the same thing is dictated by this concentration system. Also, electrons tend to move from the abode to the cathode. Likewise, electrons move from a high electrical gradient to a low electrical gradient, right? What happens as the ions move from this guy to this guy?