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Unformatted text preview: 1-23-08 anatomy notes1.Organ Systems2.Nervous Systema.Membrane Potentials and Associated Phenomenai.Action Potential1.Sequence of Eventsa.Axon at Resting Potential (-70mV)i.MUST be at resting potentialb.Portion of axon must receive an adequate stimulusi.Heat, cold, electrical, mechanical, or chemical stimulusc.Increased Na Permeabilityi.Electrical shock given to one piece of axon causes increased Na permeabilityii.Na moves ECF moves into ICF through special channels called Sodium Voltage Gated Channelsiii.Enough Na enters axon, such that electric charge reversesd.Reversal of electrical chargefull depolarization resulting in action potentialAction Potential1.Adequate Stimulus2.RP (-70mV) moves to threshold (-55mV)3.-55mV morea.Na voltage gates open4.1-4 fulla.depolarizationb.-70-30 (action potential)c.-70-80: hyperpolarizatione.Repolarization-follows depolarizationi.At 30mV, Na voltage gates closeii.K voltage gates open1.K moves from ICFECF2.Loss of K creates charge in ICFa.pos. 30-80mVf.f....
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