In the presence of a non-diffusible ion (e.g. protein),
--> The diffusible ions (e.g. K+ and Cl-) will redistribute such that...
--> Ratio of [K+] across the membrane = ratio of [Cl-] across the membrane
At such equilibrium
--> There is unequal distribution of diffusible ions and electric charge
Thus,
[KB2:p7]
Portein is present in higher level intracellularly
* Non-diffusible anion
--> Gibbs-Donnan equilibrium
--> Unequal distribution of diffusible ions and electric charge
--> Water move into cells
Sodium is the main extracellular cation, due to
* Low membrane permeability
* Active extrusion by Na-K pump
--> second Gibbs-Donnan equilibrium
--> Water moves out of cells
In equilibrium, the two effects balance out and cell volume remains stable
If Na-K pump is inhibited
--> Cell will swell and rupture due to the first Gibbs-Donnan equilibrium