RESTING MEMBRANE POTENTIAL & ACTION POTENTIAL MR. Arjun Maitra Assistant Professor Dept. of Physiology PCMS&RC
TO MY STUDENTS HERE I HAVE TRIED TO SIMPLIFY THE HUGE SUBJECT WITH ANIMATIONS, DIAGRAMS, FLOW CHARTS & RELEVENT MCQs. DIFFERENT TEXT BOOKS AND REFERENCE BOOKS HAVE BEEN USED FOR PREPARING THE CONTENTS. SLIDES ARE NOT THE SUBSTITUTE REMEMBERTHESE SLIDES ARE NOT THE SUBSTITUTE OF YOUR TEXT BOOKS ANIMATIONS AND DIAGRAMS ARE COLLECTED FROM DIFFERENT WEBSITE SOLELY FOR EDUCATION PURPOSE.
Nernst Equation & Equilibrium Potential ELECTRICAL DRIVING FORCE = CHEMICAL DRIVING FORCE E K = -75mV (Nernst Potential)
Neurons are complicated as they have Resting channels for Different ion species
GOLDMANS EQUATION A new approach to quantify the contribution of different ions Concentration gradient Conductance/Permeability PERMEABILITY RATIO (At Rest) P K : P Na : P Cl = 1.0: 0.04 : 0.45 (At peak of Action Potential) P K : P Na : P Cl = 1.0 : 20 : 0.45
ELECTRICAL EQUIVALENT CIRCUIT Conductance = 1 / ohm R Unit expressed as S = Siemens Ohms Law V=IR => I =V/R => I = V g Na= n Na X a g K = n K X g Cl= n Cl X Cl