KAAP220 Lecture Notes - Lecture 22: Sodium Channel, Axon Terminal, Membrane Potential
28 Nov 2018
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Document Summary
Membrane potential = potential difference across a membrane due to unequal charge distribution across the membrane. Inside of membrane slightly negative compared to outside. Results from difference in permeability of cell membrane to various ions and from active transport mechanisms. Resting membrane potential (resting potential) = membrane potential of an undisturbed cell; starting point. Graded potential = temporary, localized change in resting potential, produced by a typical stimulus. Decreases with distance from stimulus (graded potential) Action potential = electrical event that involves one location on the axon membrane but then spreads along axon surface toward axon terminals. Neurotransmitter binds to receptors on postsynaptic cell membrane; changes permeability and produces graded potentials in postsynaptic cell membrane. Response of postsynaptic cell depends on action of stimulated receptors and other stimuli acting on cell at same time. Simplest form of information processing in nervous system. Extracellular fluid (ecf) has high concentrations of sodium ions and chloride ions.
