Membrane potentials Flashcards
Where is sodium highest?
Outside the cell
Where is potassium highest?
Inside the cell
What does the equilibrium potential depend on?
Concentration gradient and electrical potential difference
What is an eqn used to estimate equilibrium potential for a given ion?
Nernst eqn
Approx. concentration of sodium outside the cell?
140mM
Approx. concentration of sodium inside the cell?
14mM
Approx. concentration of potassium inside the cell?
120mM
Approx. concentration of potassium outside the cell?
4mM
Typical equilibrium potential for sodium
+65mV
Typical equilibrium potential for potassium
-95mV
For uncharged substances, what is considered for equilibrium potential?
ONLY concentration gradient
How would you calculate the net driving force?
Membrane potential - Equilibrium potential
If the driving force is negative what happens?
Cations will enter the cell and anions will leave
If the driving force is positive what happens?
Anions will enter the cell and cations will leave
If the driving force is zero what happens?
No net movement
Movement of ions between the ECF and ICF causes what?
Ionic current