KIN110 Lecture Notes - Lecture 14: Gap Junction, Axon Terminal, Die Shrink
14 Sep 2016
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Review of nervous system basics the resting membrane potential. Resting membrane potential changes can be produced by changing the membrane permeability: ex. Changes give rise to two types of signals: graded potentials and action potentials. Two ways in which the membrane potential changes: depolarization: decrease (eg. -70mv=>-65mv). Increases probability of nerve impulses: hyperpolarization: increase (eg. -70mv=>-75mv). Used to transmit nerve signals over a short distance. Brief reversal of potential in short membrane patch. Magnitude and distance varies with stimulus strength. Used to transmit nerve signals over long distances. Brief but more intense - reversal of potential in short patch of membrane. Differences from graded potentials: do not decay with distance, typically occur in axons, begin as graded potentials in dendrites/cell bodies, If the stimulus increases you don"t get a stronger impulse. Depolarization must reach a threshold value or axon will not re.
