Question

What's the fundamental difference between "resting" and "equilibrium" membrane potentials? If a cell is at its "resting" potential, does that mean it is at equilibrium? And help me explain throughly.

Answer 1

The equilibrium membrane potential or just equilibrium potential is the potential in which the system is open (all molecules are free to diffuse) and a equilibrium will be created based on the chemical potential and the electric potential (in total the electrochemical potential).

The resting membrane potential is the potential in which the system is closed (the molecules are no longer free to diffuse) creating a potential which can be different from the equilibrium electrochemical potential.

Answer 2

It should then be no surprise that if then open the closed system, the electrochemical driving force should be:
\(\large V_{DF}=V_{ \sf membrane~potential} - V_{\sf equilibrium~potential }\)

Answer 3

For each ion, the equilibrium (or reversal) potential is the membrane potential where the net flow through any open channels is 0.

Answer 4

@Robert136 @grimesssz @Rushwr @shortyyshayy

Answer 5

i have no idea

Answer 6

Vm is the resting potential for the membrane, and takes into account all of the ions involved, as well as their relative permeabilities (since there is some leakage of ions, even when the membrane isn't depolarizing).

E(ion) is the equilibrium potential - it refers to a single ion, and it's the potential at which electrical and diffusional forces cancel each other out. It's the voltage at which there will be no more net flow for a particular ion, when the membrane is permeable to that ion.

Answer 7

@RamiroCruzo

Answer 8

Hi
If a cell is at its "resting" potential, does that mean it is at equilibrium? And why or why not.

Answer 9

resting potential is membrane potential when the cell is not under stimulus .
*equilibrium potential for each ion is the membrane potential value needed to stop the net movement of that ion .

Answer 10

Resting Membrane Potential (RMP) is the voltage (charge) difference across the cell membrane when the cell is at rest.The resting membrane potential of a neuron is about -70 mV

The equilibrium (or reversal) potential is the membrane potential where the net flow through any open channels is 0. i.e. the ion potential inside & outside cancel out each other, which in case of neuron would be 70mV inside & 70mV outside, hence no total charge.

So, we can conclude that if a cell is at its "resting" potential, that doesn't mean that it is at equilibrium.