Equilibrium and Action Potentials 3.0 / 5 based on 1 rating ? BiologyUniversityOther Created by: jessicaCreated on: 18-12-12 14:45 What equation is used to find the equilibrium potential for an ion? Nernst equation 1 of 16 What are the 2 important pumps in cellular neurophysiology? Sodium-potassium pump and the calcium pump 2 of 16 What equation is used to find the resting membrane potential? The Goldman equation 3 of 16 What is the structure of the potassium channel? 4 subunits arranged in a barrel forming a pore with the pore loop acting as a selectivity filter 4 of 16 What are the stages in the generation of an action potential? Rising phase, Overshoot, Falling phase, Undershoot and Restoration of the resting potential. 5 of 16 What happens in the rising phase of the action potential? There is rapid depolarization of the membrane changing the membrane potential until it peaks at 40mV. 6 of 16 What happens in the Overshoot phase of the action potential? The action potential on the inside of the neuron is positively charged in comparison to the outside 7 of 16 What happens in the Falling Phase of the action potential? There is rapid repolarization until the membrane is more negative than the resting potential 8 of 16 What happens in the Undershoot phase of the action potential? It is the last part of the falling phase where the is gradual restoration of the resting potential. 9 of 16 How long does an action potential last? 2msec. 10 of 16 What is the absolute refractory period? The period of time between each action potential 11 of 16 What is the relative refractory period? It occurs after the absolute refractory period and is during this period that the action potential threshold is higher than normal 12 of 16 How is the cell depolarizied? By an influx of Na+ ions across the membrane 13 of 16 How is a cell repolarized? By an efflux of K+ ions 14 of 16 What is the structure of a voltage gated sodium channel? A single peptide with 4 domains, each having 6 transmembrane alpha helices, forms a pore which is closed at the negative resting membrane potential. 15 of 16 How is the voltage gated sodium channel pore opened? There is a voltage sensor in the fourth transmembrane protein which twists when the threshold is reached opening the pore. 16 of 16
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