You are studying the effects of ion concentration and ion conductance on the membrane potential. Assume that all ions are at equilibrium. Ignore membrane capacitance. Remember that membrane potential is measured inside the cell with reference to outside the cell. For the table below, find the expression and solve for the sodium concentration outside the cell and the potassium concentration inside the cell. Using circuit analysis techniques, find the expression and solve for the membrane potential at equilibrium given the conductances for the three ions. In an unknown neurodegenerative disease, the conductance of potassium is reduced from 30 pS to 2 pS. Sodium and chloride conductances remain the same. Calculate the new equilibrium membrane potential. Assuming the conductances for K+ and Cl- both remain the same, what should the conductance of Na+ be so that the equilibrium membrane potential is 0 mV? Is this new conductance higher or lower than the original conductance of 2 pS? Does this answer make sense? Explain why or why not.

Ion	Concentration (mmol/L H20)		Equilibrium Potential (mV)	Conductance (pS)
	Inside Cell	Outside Cell
Na+	11.0	??	+60	2 pS
K+	??	7.0	-80	30 pS
Cl-	7.0	120.0	-74	5 pS