Medical Definition of Nernst equation
1.
A basic equation of biophysics that describes the relationship between the equilibrium potential difference across a semipermeable membrane and the equilibrium distribution of the ionic permeant species.
It is described by: E = (RT/zF).ln[C1/C2
Where E is the potential on side 2 relative to side 1 in volts), R is the gas constant (8.314 J Kexp 1 molexp 1), T is the absolute temperature, z is the charge on the permeant ion, f is the Faraday constant (96500 C molexp 1) and C1 and C2 are the concentrations (more correctly activities) of the ions on sides 1 and 2 of the membrane.
It can be seen that this equation is a solution of the more general equation of electrochemical potential, for the special case of equilibrium. The equation described the voltage generated by ion selective electrodes, like the laboratory pH electrode and approximates the behaviour of the resting plasma membrane (see resting potential).
(13 Nov 1997)
Lexicographical Neighbors of Nernst Equation
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