Resting Membrane Potential Flashcards
what creates a concentration gradient across the membrane?
The Na+-k+ ATPase pump
3Na+ out and 2K+ in
What prevents K+ reaching full equilibrium?
Positive charge carried out of the cell resists further ion movement
Why is the membrane potential is smaller than the predicted value?
other ions like Na+ can leak through membrane so not -95 but -60/70
Important principles
what does the phospholipid bilyaer create?
what drives the membrane to equilibrium?
why is it only theoretical equilibrioum?
The phospholipid bilayer creates an impermeable membrane, that is studded with pumps and channels formed from proteins.
K+ leaking out drives the membrane potential towards a theoretical equilibrium at -95mV.
The membrane isn’t perfectly impermeable to other ions.
Other ions, in particular Na+, leaking through the membrane prevent perfect equilibrium from being reached.
- ** The actual membrane potential tends to be between
- 60 and -70mV ***
