Passive Membranes Answer 6

• From the answer to the previous question, it became clear that the net flux of potassium ions would be into the cell, creating a current of positive ions flowing into the nerve cell.
• By adding positive charges to the inside of the nerve cell, the excess negative charges that had been injected would be neutralized, and the charge separation across the membrane will diminish.
• Thus, the effect of the influx of potassium ions will be to reduce (move toward 0 mV) the membrane potential.
• This will continue until the membrane potential has returned to its previous value, that is, 0 mV.
• Although we have made this problem easier to solve by making the concentrations equal on the inside and outside, the same results of injecting charges would occur if the equilibrium potential were not initially at 0 mV.
• If the membrane potential were made more negative through charge injection, potassium fluxes into the cell would increase, neutralizing the change.
• By the same logic, if the membrane potential were made more positive through charge injection, potassium fluxes out of the cell would increase, neutralizing the change.