NROB60H3 Chapter Notes - Chapter 4: Voltage Clamp, Patch Clamp, Saxitoxin
13 Dec 2016
School
Department
Course
Professor
Document Summary
Action potential, membrane potential becomes positive for a brief time. Oscilloscope: record the voltage of membrane in neurons as it changes over time. Overshoot: inside of neuron is more positively charged than the outside. Falling phase: rapid repolarization will be slightly more negative than at resting potential. Undershoot: when the membrane potential is lower than resting. Then, gradually goes back to -65 mv potential. Generate action potential: na+ channel open and move into the neuron, the charge of the cytoplasm of the neuron becomes more positive depolarization. If depolarization reaches a critical level, action potential will be generated. What causes the na+ channel to open depends on the type of neuron. Sensory neurons use external stimuli (eg. prick of thumb) Passing continuous current through neuron will cause multiple action potentials. Firing frequency of action potentials reflected by the current used to depolarize cell: more current = faster depolarization = faster action potentials, maximum firing frequency of 1000hz.
