Action Potentials

Action Potentials - Action Potentials If the total...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Action Potentials If the total electrical activity of the cell results in a depolarization past threshold at the trigger zone , then the neuron will fire an action potential . The opening of the voltage-gated Na + channels on the axonal membrane causes the axonal membrane to depolarize beyond 0 mV and peak at ~ +35mV. The VG-Na + channels inactivate and delayed VG-K + channels open, allowing the efflux of K + from the cell, repolarizing the axonal membrane. These VG-K + channels remain open slightly longer than necessary to repolarize the axonal membrane, resulting in a slight overshoot of the RMP. In contrast to local potentials, APs are all-or-none , non-decremental , and irreversible . Refractory Periods The slight overshoot of the RMP at the end of the AP results in a period of resistance to further stimulation known as a refractory period. The absolute refractory period is the time when no stimulus, no matter how strong, can trigger an AP. This occurs as long as the VG-Na + gates are
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/30/2012 for the course BSC BSC1085 taught by Professor Sharonsimpson during the Fall '10 term at Broward College.

Page1 / 2

Action Potentials - Action Potentials If the total...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online