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Unformatted text preview: Biology 100, Fall 2008 (rev. 05/06/08) Notes on the Nervous System (see Chap 45) The Resting Potential : Inside of cell body and axon is negative (approx. -70 mV ) when there are no nerve impulses occurring . The resting potential is nearly the same as the potassium equilibrium potential . It is present because (a) the resting nerve cell membrane is mainly potassium permeable and (b) there is a potassium ion (K + ) gradient across the membrane. Special Terms: Depolarization = more positive (upward from the resting level) Hyperpolarization = more negative (downward from the resting level) The Action Potential = Nerve Impulse: Ion Gradients Electrical Signal (nerve impulse)-- Na + conc. high on outside-- K + conc. high on inside--> Gradients maintained by action of Na-K pump (which uses ATP) Signal: -70 mV --> +30 mV --> -70 mV ==> 100 mV amplitude...
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This note was uploaded on 01/22/2011 for the course BIO 100 taught by Professor Sokolove during the Fall '08 term at UMBC.
- Fall '08