In a cell, assume that only sodium, potassium, chloride and calcium ions can cross the membrane and their currents are: $I_{Na}$, $I_{K}$, $I_{Cl}$ and $I_{Ca}$, across the whole membrane. There is also an electrode inserted into the cell. Its current is $I_e$.
I want to find a relationship between these currents. I think it should be something like this:
$I_{Na} + I_{K} + I_{Ca} = I_{Cl} + I_e$
Am I correct?
