PSYC 2390 Lecture : Lecture January 12
22 Jan 2012
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Document Summary
The inside of the cell has more negative ions relative to the outside. Membrane is selectively permeable lets in some substances but not others. Negative membrane potential resting potential (70 millivolts) action potential (40 millivolts) Action potential occurs when the selective permeability of the membrane changes for half a millisecond and sodium comes into the intracellular fluid and potassium gets booted out. Membrane potential goes lower then 70 millivolts and then has a recovery phase, gates close and potassium cant get out. Slight delay between one action potential and the next it takes a while to get the cell ready for another action potential. When there is an action potential the change is always the same either you have one or you don t. Occurs when you haven t stimulated a neuron enough to get an action potential. Graded potentials fade away and never make it to the end of the axon.
