Generation of the Action Potential

What is the magnitude (amplitude) of an action potential?

100 mV [the membrane goes from -70 mV to +30 mV. Thus, during the action potential, the inside of the cell becomes more positive than the outside of the cell.]

Where in the neuron is an action potential initially generated?

axon hillock [this region (first part of the axon) receives local signals (graded potentials) from the soma and dendrites and has a high concentration of voltage-gated Na+ channels.]

Hyperpolarization results from __________.

slow closing of voltage-gated K+ channels [ the slow closing of the voltage-gated K+ channels means that more K+ is leaving the cell, making it more negative inside.]

The repolarization phase of an action potential results from __________.

the opening of voltage-gated K+ channels [as the voltage-gated K+ channels open, K+ rushes out of the cell, causing the membrane potential to become more negative on the inside, thus repolarizing the cell]

The depolarization phase of an action potential results from the opening of which channels?

voltage-gated Na+ channels [when the voltage-gated Na+ channels open, Na+ rushes into the cell causing depolarization.]