Lecture%205

Lecture 5 - Lecture 5 Outline action potential conduction synaptic transmission pre-synaptic events and postsynaptic events excitatory and

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Lecture 5 10/7/04 Outline: action potential conduction, synaptic transmission: pre-synaptic events and post- synaptic events, excitatory and inhibitory synapses, convergence and divergence, Action Potential -local effect in an excitable membrane due to the opening of Na+ channels- positive feedback loop- more and more depolarization until all channels are open -a propagated signal because it regenerates itself -speed depends on: 1. length of axon (short length = small fiber = small diameter, and more action potentials are needed to travel the distance) -in a larger axon, a action potential can influence more area 2. speed increases with increased diameter (range of .1m/sec to 100m/sec) 3. greatly increased with myelin - gives salutatory conduction -the jumping of action potentials down myelinated axons; “jumps from one node of Ranvier to the next -fast and slow fibers needed -to move your pinky toe if 2 way conduction: motor neuron in the spinal cord would send an action potential doesn axon to your toe, and that action potential would generate another going back up to the spine, which would generate another back down the spine- an infinite loop of action potentials-
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This note was uploaded on 04/02/2008 for the course BILD 26 taught by Professor Aaa during the Fall '06 term at UCSD.

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Lecture 5 - Lecture 5 Outline action potential conduction synaptic transmission pre-synaptic events and postsynaptic events excitatory and

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