Action Potentials Flashcards
1
Q
What are all of the 6 elements of action potentials?
A
resting potential generator potential threshold depolarisation repolarisation hyperpolarisation
refreactory period
2
Q
What is the resting potential?
A
- sodium potassium pump
- active transport - using ATP
- Na+ diffused out
- K+ pushed in
- Some K+ diffuse out via potassium ion channel
3
Q
What is the generator potential?
A
- weak stimulus
- some sodium ion channels will open
- some sodium ions diffuse in but dont reach threshold
- sodium potassium ion pump restores resting potential
4
Q
What is the threshold?
A
- generator potential reaches threshold
- many voltage gated sodium ions channels open
- sodium ions diffuse into axon
- positive feedback
5
Q
What is depolarisation?
A
- sodium ion channels are open
- sodium ions diffuse in
6
Q
What is repolarisation?
A
- potassium ion channels open (voltage gated)
- potassium diffuses OUT
- voltage gated sodium ions close
7
Q
What is hyperpolarisation?
A
- membrane potential is more negative than the resting potential
- potassium channel ions are slow to close
8
Q
What is the refractory period?
A
- action potential cannot be triggered - can’t start a new one
- makes action potentials discrete (dont overlap) and unidirectional (one way)
