BIOL 306 Lecture Notes - Lecture 10: Resting Potential, Depolarization, Reversal Potential
15 Jan 2018
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You never need to worry about depleting k+ storage of ions. Q: in a k+ cell at resting potential, increasing extracellular concentration of k+ will cause a depolarisation. Increasing positive charge outside the side, indirectly making inside of cell more negative. Will cause depolarisation to balance out charges again. For this cell, ek = 0 cell needs to become more positive (from -58mv) cells need to flow in. Reversal potential = no net current = equal amounts of inside & outside currents = x-intercept in iv curve. Electrochemical driving force = vm - ei. A: vm of neuron is approaching sodium"s nernst potential. Dependent on resistance and capacitive properties of neuron. Higher capacitance = longer it takes to charge. Smaller tube = more resistance = "axial resistance" = ra = resistance conductor. How long it takes to retain 37% or lose 63% Passive vs. active neurons active neurons have voltage-gated channels.
