ACTION POTENTIAL

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Created by
Jasmine Singh

Cards (6)

  • WHAT IS AN ACTION POTENTIAL?
    temporary reversal of charges either side of part of the axon membrane after a stimulus of sufficient size is detected
  • WHAT IS THE ACTION POTENTIAL VALUE?
    +40 mV
  • WHAT IS THE AXON DESCRIBED AS IN AN ACTION POTENTIAL?
    depolarised
  • PROCESS OF ACTION POTENTIAL?
    1. NaVGCs closed at resting potential
    2. Some KVGCs are open
    3. Energy of stimulus = some NaVGCs open
    4. Na+ diffuse into axon via channels down electrochemical gradient
    5. Positive charge triggers PD reversal
    6. More NaVGCs open
    7. Greater influx of Na+ by diffusion
    8. Action potential of +40 mV reached = NaVGC close and KVGC open
    9. Electrical gradient reversed
    10. More KVGC open
    11. More K+ diffuse out
    12. Temporary overshoot of electrical gradient (hyperpolarisation)
    13. Some KVGCs close
    14. Na-KP pumps out Na+ and pumps K+ in
    15. Resting potential re-established (repolarised at -65 mV)
  • WHAT IS HYPERPOLARISATION?
    when the inside of the axon is more negative than usual
  • VALUE FOR HYPERPOLARISATION?
    -90 mV