BRAINCAKEAction Potential
An action potential is a brief reversal of the potential difference across the membrane of a neurone, from about −70 mV (inside negative) to about +40 mV (inside positive). It lasts about 2 to 3 ms and is caused by the opening and closing of voltage-gated ion channels.
The sequence of events is shown on a graph of membrane potential against time:
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More in Mammalian Nervous System
- Myelinated Neurones
- Speed of Nerve Impulses
- Investigating Nerve Impulses
- Resting Potential
- Depolarisation
- Repolarisation
- Hyperpolarisation
- Refractory Period
All 38 lessons in Mammalian Nervous System · All Edexcel A-level Biology topics