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5 Cards in this Set
- Front
- Back
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How are electrical impulses generated? |
They are generated by changes in the concentration of ions inside and outside the nerve cells causing a potential difference (Pd) called action potential. |
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What happens in depolarisation? |
The sodium gates open, the sodium diffuses into the cell carrying positive charge. Then the sodium gates closes when it has reached tresh hold. |
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What happens in repolarisation? |
The potassium gates open. Potassium diffuses out of the cell taking positive charge with it and the potassium gates close. |
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What happens in recovery? |
In recovery the potassium moves back into cell through non-voltage gated channels. Attracted by negative charge as hyperpolarised. Resting potential is when equilibrium has been restored. |
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What is saltotory conduction? |
The only region of a myelinated nerve fibre that can depolarise is at the nodes of Ranvier where there is no myelin. Thus means nerve impulse can travel a much longer distance. They can also travel faster than without myelin and the impulse jumps from one node to the next. |
