The mentioned video provides an easy explanation about important concepts regarding movement of ions and membrane potential. Watch this one for polishing your knowledge! 00:00 Membrane Potential 00:24 Ion Movement - Factors 01:05 Concentration Gradient 02:03 Equilibrium and Equilibrium Potential 02:40 Equilibrium Potentials of Na, K and Cl 03:35 Sodium - Potassium Pump