PHYS20008 Lecture Notes - Lecture 5: Axon Hillock, Myelin, Schwann Cell
10 May 2018
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Lecture 5
- Ouabain, a specific inhibitor of the sodium potassium pump applied to neuron. The
next action potential that fires after ouabain application will appear the same as
normal.
- Action potentials are due to the passive flow of ions through the channels
- The sodium potassium pump sets the environment so that the concentration
gradients exist, long term maintenance, 3Na+ out / 2K+ in
- Refractory period: time can’t fire another action potential
- Action potentials are always the same size and shape, set by timing of channels to
be a specific event.
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- Trigger zone = axon hillock = AP initiation site, the start of axon
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Document Summary
Ouabain, a specific inhibitor of the sodium potassium pump applied to neuron. The next action potential that fires after ouabain application will appear the same as normal. Action potentials are due to the passive flow of ions through the channels. The sodium potassium pump sets the environment so that the concentration gradients exist, long term maintenance, 3na+ out / 2k+ in. Refractory period: time can"t fire another action potential. Action potentials are always the same size and shape, set by timing of channels to be a specific event. Trigger zone = axon hillock = ap initiation site, the start of axon. Absolute refractory period: voltage-gated sodium channels are in action or inactive state, absolutely cannot fire another ap because channels aren"t ready to. Ap from doubling back on self because area behind ap is in its absolute refractory period, can"t be repolarised by sodium moving in)
