BISC306 Lecture Notes - Lecture 7: Synapse, Nernst Equation, Fokker E.Ii
16 Sep 2016
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Action potentials and voltage-gated channels: donnan equilibrium, are potassium and chloride at their equilibrium potentials while at donnan equilibrium? a. i. Yes, ek+=ecl- using nernst equation to see if ions are at equilibrium while at donnan. Equilibrium: electrolyte concentrations are in steady state in a resting cell, but not at equilibrium b. i. Most electrolytes have an ex that is different from the vm b. ii. Reveals nature of ion currents during action potential c. ii. Current is injected into a cell and adjusted to hold the voltage at a predetermined value c. iii. Current measured is caused by voltage-gated channels: patch-clamp technique-can isolate and examine small patches of membrane and how one ion affects the voltage potential d. i. Gating of individual channels; response of a single voltage-gated sodium channel: current-function of the driving voltage and the conductance e. i. More open channels for that ion, the more conductance there is e. iii. Clamped at 0, there is no driving force for the ions: voltage-gated channels f. i.
