notes 3 - to conduct more smoothly w/o stopping Mylenation...

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19:28 Ions and the Action Potential Resting potential is negative: More (-) inside, more (+) outside In fact, more K+ is inside, and more Na+ outside (NA+ channel)  Depolarization   NA+ channels open   Na+ flows into cell More depolarization   Na+ channels inactivate (K+ channel)  depolarization   K+ channels open BUT SLOWLY   K+ flows out  of cell   repolarization   hyperpolarization Negative resting potential maintained by pumps and channels The action potential is self-perpetuating : Once it starts it keeps going, due to Na+ channels The action potential is self-limiting : Na+ channels inactivate and K+ chanels repolarize Action Potential Propagation: How does it have an effect @ end of axon? Passive currents (opening of channels)  depolarization (again) Action potential (again) Myelin Insulates axon of the cell Allows Saltatory Conduction; less amt of Node of Ranvier b/c of myelin allows it 
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Unformatted text preview: to conduct more smoothly w/o stopping Mylenation develops thru life So how does it actually send info to next cell? Synaptic Transmission Two main types of synapse: electrical & chemical Electrical synapse: Less common Electric current flows across the synapse Sides are linked Passive FAST (instantaneous) Biodirectional Post-synaptic cell can affect pre-synaptic cell Chemical synapse: More common Chemicals flow across the synapse Sides are not linked Unidirectional Most recreational drugs stimulate chemical neurotransmitters Cascade of Synaptic Events Action potential invades! Changes membrane potential Influx of Ca2+ Vesicles fuse with membrane Transmitters are released (exocytosis ) Diffusion across membrane Postsynaptic binding Postsynaptic changes Likelihood of action potential increases or decreases Endocytosis 19:28 19:28...
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This note was uploaded on 03/08/2011 for the course PSY 341K taught by Professor Gilden during the Spring '08 term at University of Texas at Austin.

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notes 3 - to conduct more smoothly w/o stopping Mylenation...

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