BIO PSYCH - LECTURE 3: MEMBRANE POTENTIALS

selective permeability

the membrane lets some ions pass easily (like K⁺ through leak channels) but blocks others unless they have a specific channel or pump

electrochemical gradient

the combined force of a chemical concentration gradient (difference in solute concentration) and an electrical gradient (difference in charge) across a membrane

Driving Force of Ion Movement

Vm - Eion

Difference between the membrane potential and the ion’s equilibrium potential

Ohm’s Law

Current = Conductance * Driving Force

I = g x V

Nernst Equation

calculates equilibrium potential

Goldman Equation

solves for the membrane potential given conductance and equilibrium potential

Conductance

how easily ions flow through the membrane; depends on how many channels are open

Equilibrium Potential

the specific membrane voltage where the electrical force pushing the ion across a cell membrane perfectly balances the chemical force (concentration gradient) pushing it the other way, resulting in no net movement of that ion in or out of the cell

Membrane Potential

the electrical potential difference across a cell's membrane, reflecting the distribution of ions

Current

movement of charge

Leak Channels

that allow ions to flow across the membrane, contributing to the resting membrane potential

Na+/K+ Pump

a transport protein that uses ATP to move sodium out of and potassium into a cell, helping to maintain the membrane potential