PHGY 214 Lecture Notes - Lecture 4: Procaine, Axon Hillock, Myelin
17 Jan 2017
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Document Summary
Action potential: rapid change in vm due to coordinated action of certain voltage-gated channels. Action potential code information and trigger muscles and glands. It is the language of the nervous system. (there is change of voltage when changing permeability. Ap are all or none events (not graded) All: once reaching the threshold an ap occurs. None: if it does not real it, none. Digital code - fewer aps and more aps. Stronger stimulus = more aps not bigger aps. Lots of stimulation needed to get to the threshold. The ionic permeability basis of the action potential. There is a rapid rise and fall in pna, causing depolarization, bringing it up to vna (+60) There is a slower rise and fall of pk. There is repolarization, where it begins to go back to negative vk. Then comes the hyperpolarization, where it is lower than -60mv (around -90mv) after, it comes back. The functioning of voltage-gated channels during the action potential.
