NBB 301 Chapter Notes - Chapter 3: Voltage Clamp, Alan Lloyd Hodgkin, Andrew Huxley

• School: Emory University
• Department: Neuroscience & Behavioral Sci
• Course: NBB 301
• Professor: Frenzel Kristen

Document Summary

Early influx of na into neuron (transient inward current) followed by delayed efflux of k (sustained outward outward current: two voltage-dependent membrane conductances, membrane conductance: reciprocal of the membrane resistance; related to membrane permeability. Both na and k conductances are voltage-dependent --- both conductances increase progressively as the neuron is depolarized: ionic currents that flow when neuronal membrane is depolarized are due to : Inactivation of na conductance: reconstruction of the action potential, hodgkin-huxley model, mimicked refractory period: when axon becomes refractory to further excitation for a brief period of time after an action potential. Selective increase in na conductance is responsible for action potential initiation. Rate of depolarization falls b/c electrochemical driving force on na decreases and b/c na conductance inactivates: hyperpolarization of membrane potential --> k conductance turns off --> membrane potential returns to resting. Positive feedback loop of activation voltage-dependent na conductance.