Lecture 3: Equilibrium, Resting Membrane, and Action Potentials Flashcards
what is the potential difference that exists across membranes in the period between action potentials
resting membrane potentials
how is RMP established
diffusion potentials
defined as the potential difference generated across membrane when a charged ion diffuses down concentration gradient
- ca be + or -, depending on charge of ion
diffusion potentials
how is diffusion potentials set and maintained?
K+ leak channels and mainted by Na+/K+ ATPase pump
ions with low/high permeabilities contribute most to RMP
high
- K+ seperated from immoble anions inside cell
________ flows out of cells through leak channels and carries a + charge and sets RMP
K+
what is the RMP range
-70 to -80 mV
what transporter pump brings K+ back into the cell to keep gradient increase in cell
- helps maintain K+ concentration gradient across the membrane
- Helps to set K+ diffusion potential
Na+/K+ ATPase
what type of potential is a diffusion potential that opposes the tendency for further diffusion of an ion down a concentration gradient
equilibrium potential
what type of potential differences across the cell membrane that exactly balances the concentration gradient for an ion
eletrical potential
when is the membrane at rest?
net flow of ions across membrane is zero = rest
how do you calculate driving force?
difference between the measured membrane potential and the ions calculated equilibrium potentil
what happens if driving force is negative
ion will enter the cell if it is a cation and leave the cell if it is an anion
what brings membrane potential back to normal if membrane potential is too negative
driving force
define the following?
- transmit information in nervous system and all muscles
- occurs in excitable cells - rapid depolarization followed by repolarization
Action Potentials
