ACTION POTENTIALS Flashcards
1
Q
what are 3 things they are looking for in your answer?
A
- Name of ion channel
- Do they open or close?
- Movement of ions
2
Q
what is happening at resting potential?
A
- Na+/K+ pump actively transports 3 Na+ out/2 K+ in
- some K + diffuses back out down electrochemical gradient
3
Q
what is happening at the generator potential?
A
- a weak stimulus causes some Na+ channels to open so some Na+ diffuses IN
- threshold not reached
- resting potential is restored by the Na/K pump
4
Q
what is happening when threshold reached?
A
- generator potential reaches threshold so many v-gated Na+ channels open
- Na+ diffuses into axon
5
Q
what is happening during depolarisation?
A
- V-gated Na+ channels are open and Na+ is diffusing in
6
Q
What is happening during repolarisation?
A
- voltage gated K+ channels OPEN so K+ diffuses out
- V-gated Na+ channels close
7
Q
what is happening during hyperpolarisation?
A
the membrane potential is more negative than the resting potential because K+ channels are slow to close
8
Q
what is the refractory period?
A
- when another action potential cant be started
- ensures they are discrete and unidirectional
