Question

Can someone please explain membrane potential, diffusion potential, and equilibrium potential and any way they may be related? Also, what is each thing dependent on, and what are the units used to measure each?

Answer 1

The membrane potential is the difference in electric potential in and out side of the cells and the membrane potential ranges between -40 to -80mV(milli volts).

Diffusion potential is defined as the potential difference caused due to difference in concentrations of ions and is only found in membranes permeable to ions. Moreover, the size of diffusion potential depends on size of concentration gradient and is indicated with ' + or -.' sign depending on positive or negatively charged ions diffusing across the membrane.

Equilibrium potential is defined as the diffusion potential that balances the diffusion ions and the concentration differences. in an electrochemical equilibrium, the chemical and electrical forces acting ions are equal and opposite. Therefore, at equilibrium potential, there is no net diffusion of ions.

Resting memebrane potential is potential difference across membrane inside and outside of membrane and is usually -70mV. The resting membrane potential is generated by the diffusion potentials of permanent ions and the concentration differences. Each permanent ion diffusing across the cell tends to drive the membrane potential toward equilibrium potential producing equilibrium gradient and no net diffusion of ions across the membranes.

All these tytpes of potentials are measured by millivolts (mV).