resting membrane potential Flashcards
1
Q
what is the resting membrane potential of a cell
A
the electrical potential difference across the plasma membrane when the cell is in a non-excited state
2
Q
membrane potential [Vm] is determined by
A
- distribution of ions intra and extracellularly
- variation on the membrane permeability to different ions
3
Q
the resting potential of an average neuron
A
-70mV
4
Q
diffusion potential
A
the voltage at which the electrostatic force on an ion is equal and opposite to the chemical force on the concentration gradient
5
Q
electrochemical gradient- steady state
A
- no net force, no net ion flow
- no further change in ion conc at plasma membrane
- no further change in charge distribution or membrane potential
6
Q
when Vm>Ek
A
- constant flow of ions across the plasma membrane
- Na+ moves in and K+ moves out
- the number of ions moved is very small
7
Q
role of Na+/K+ -ATPase
A
- to replenish K+ lost from the cell
- to remove Na+ accumulated within the cell
8
Q
the sodium potassium pump
A
- outer membrane of the cell
- helps maintain cells membrane potential- maintains gradient
- primary potassium pump