L5 Cell Membrane Potentials Flashcards
every biological solution is what?
equivalence/”electro-neutral” - for every + charge there is a - charge
define the resting membrane potential?
the difference in charge that exists between the cell interior and exterior
what is the membrane potential based on?
whatever ion is most permeable to membrane - usually K+
how are resting membrane potentials set up?
by ionic gradients and the channels present in the membrane
what is the RMP for an epithelial (non-excitable cell)?
-50mV
what is the RMP for a neuron (excitable cell)?
-80mV
define electrical potential difference?
when there is an unequal amount of + and - charges between 2 compartments
what two factors affect the resting membrane potential?
permeability of cell membrane
concentration gradient against cell membrane
when is the electrochemical gradient = 0?
when the chemical and electrical gradient are equal and opposite
what is the equation for EC gradient?
EC gradient = chemical gradient + electrical gradient
how can we calculate Nerst potential/equilibrium potential (Em)?
from the ionic concentration gradient… I can do these!
what is the equation for driving force?
DF = Vm - Em
define membrane potential?
potential difference between the inside and outside of the cell - the cell will set this we can measure it Vm
define equilibrium potential?
potential at which there is no flux of ion - we calculate this Em
what happens to flux the further away you get from Em?
more flux!
