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Unformatted text preview: REV: Nernst vs GHK
REV: REV: Action Potentials
REV: Phases of the Action Potential Fig. 4‐4, p. 91 Fig. 4‐5, p. 92
Rat cardiac cell Frog twitch muscle Phases of the Action Potential (cont’d) Fig. 4‐7, p. 94 The Action Potential is directed by
changes in membrane permeability
Channel behavior affects
firing rate • Recall Na+ channel inactivation Absolute Refractory Period • Na+ channels are inactivated
• Lasts until repolarization
• No stimulus can initiate another AP Relative Refractory Period Fig. 4-11, p. 99 • Some Na+ channels still inactivated
• Potassium current still hyperpolarizing
• Can trigger an AP with strong stimulus Action Potential Propagation
Initiated by graded potentials Changes in Membrane Potential Fig. 4‐1, p. 88 Passive Propagation along a membrane
Fig. 4‐2, p. 89
Fig. 4‐3, p. 90 • The voltage change across the membrane gets
smaller with distance from the initiation zone. Action Potential Propagation (cont’d)
• The spread of excitability in a neuron
is directional Fig. 4‐9a, p. 97 Fig. 4‐8, p. 95 Action Potential Propagation (cont’d)
Contiguous Conduction Fig. 4‐9, p. 97 ...
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This note was uploaded on 11/24/2011 for the course NPB 97952 taught by Professor ? during the Spring '09 term at UC Davis.
- Spring '09