BIOL 3P34 Lecture Notes - Lecture 9: Voltage Clamp, Afterhyperpolarization, Negative Feedback
12 Oct 2016
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Document Summary
Action potentials: potential changes across the membrane, conduct signals over long distances, encode information (their frequency and pattern does this) Ionic basis of the action potential: overton (1902) had hypothesized that an action potential might be due to. Na+ entering a cell: ionic mechanisms were not explained until 40 years later, conductance experiments were done on a squid membrane, found the membrane. Experiments by hodgkin and katz: was more permeable to ions during the ap. Proposed: change in permeability of the membrane from predominantly k+ to na+ What would happen if na+ channels opened in the membrane and permeability to. Na+ increase: inflow of na+ ions would depolarize the membrane, high permeability to na+ would drive the vm towards ena (+55mv) Overshoot: the inside of the membrane becomes more positive than the outside. Afterhyperpolarization (ahp): some potassium channels are still open and there is an efflux of positive charge, vm is more negative.
