NROB60H3 Study Guide - Final Guide: Inhibitory Postsynaptic Potential, Resting Potential, Axon Terminal
Document Summary
The ups and downs of an action potential. Neuronal membrane at rest, the voltmeter reads a steady potential difference of about -65 mv. During the action potential, the membrane potential brie y becomes positive. Oscilloscope is used to study action potentials - records the voltage as it changes over time. The rst part = rising phase -characterized by a rapid depolarization of the membrane. Inside of the neuron is positively charged with respect to the outside = overshoot. Falling phase - rapid repolarization until the inside of the membrane is actually more negative than the resting potential. This last part of the falling phase = undershoot or after-hyperpolarization . Finally, there is a gradual restoration of the resting potential. Critical level of depolarization that must be reached in order to trigger an action potential = threshold. The depolarization that causes action potentials arises in different ways in different neurons.
