5-Elec Signals Neurons Figs BW

No its 10 the is hashmark the current is always same

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Unformatted text preview: litude. the duration at which channel open varies with the normal distribution at some mean. basically channel is either on or off. what we are looking through current of potassium ion through ion channel. -change membrane potential:clamping means that you set the membrane potential at some level and you clamp it there (hold it there). here clamping is hold at normal resting potential. in the next experiment, we will depolarize the membrane. Endolymph im Current Patch clamping Time - 10 pA -0 100 ms top=at normal resting level. bottom=what signal ion channel look when depolarize. use Olm's law: current (movement of charge),voltage (force making charge move), resistance( property that impede flow). current directly proportional to the voltage driving the charge and inversely proportional to the resistance opposing the movement. directly proprtional to the voltage driving the movement is the difference between membrane and equilibrium potential. if force is positive, negative=inward movement. think resistance in terms of conductance (opp. of resistance). the current carry by ion is =conductance xdriving force. -conductance is not same as permeability (chemical term referring to mass of ions move across membrane). conductance (charge of ion move across membrane) is an electrical term like resistance (1/R) Depolarization Affects Single Channel Currents Open - i Closed conductance (g)=1/R I(ion)=g(ion)[Vm-E(ion)] Depolarization Current Time Open Closed open more frequently. though time it increase is same. • Increase in probability of opening • Increase in amplitude of current I is bigger For single channel currents Ohm’s Law V I= R i= Vm - Eion R so you can see why the amplitude increased when you depolarized because the memory potential with depolarization is moving away from equlibrium potential for potassium, so driving force increase. the equilibrium is more negative while resting is more postive than Ek. when membrane is depolarize, potential become even more positive, driving force is greater....
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This document was uploaded on 03/09/2014 for the course EXSC 301 at USC.

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