Electrical Properties of Membranes Flashcards
When charges will stop crossing the membrane, when will the equilibrium be reached?
When the diffusice force equals the electric force.
On what parameter does the diffusive force depends?
On the Temperature.
Which is the voltage potential of a membrane in equilibrium?
-70mV
The Nermst Potentail
Would the inner and outer concentrations remain constant?
If there is ion influx.
Yes, as the ions that cross the membrane are a tiny amount compared to the total amount of ions.
Would the total charge be different to 0?
It is ALWAYS 0 when we are far from the membrane.
Which ion has a higher Nermst potential, which one the lowest?
Na+ = +60 mV
Cl- = -70 mV
K+ = -90mV
When we consider that the membrane is ONLY permeable for this ions.
Which is the order of the permeabilities of the ions?
pNa lower than pCl and lower than pK=1.
Which is the resting membrane potential?
-70mV
To recover the resting potential…
When there is an increase of voltage?
And the Electrive Force is reduced.
It will try to increase the Elective Force by moving the K+ charges outside.
To recover the resting potential…
When there is a decrease of voltage?
And the Electrive Force is increased.
The electrive dorce will be reduced by moving K+ inside.
Which ion channels open faster?
Na+ channels
What happens when the K+ channels open?
That the potential growth rate is reduced.
Goes slower.
What parameter changes during the action potential?
ONLY changes in the membrane permeabilities.
NO CHANGE IN THE CONCENTRATIONS OF THE IONS.
More pores means that there is a LOWER/HIGHER effective resistance.
LOWER
Rt= R pore /N
What is capacitance?
The ability to store charge.
