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10 Cards in this Set
- Front
- Back
1 |
An action potential arrives at the axon terminal of the presynaptic neurone. |
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2 |
The action potential causes voltage-gated calcium ion channels to open in the presynaptic terminal. |
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3 |
Calcium ions diffuse into the axon terminal (synaptic knob). |
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4 |
This promotes the synaptic vesicles containing neurotransmitter (acetylcholine, ACh) to move to the presynaptic membrane. ACTIVE PROCESS SO REQUIRES ATP |
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5 |
The influx of calcium ions promotes the neurotransmitter to be released via exocytosis. |
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6 |
The neurotransmitter quickly diffuses across the synaptic cleft. |
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7 |
2 ACh molecules bind with 1 ligan-gated sodium channel at the postsynaptic membrane. This opens the sodium ion channels but doesn't let ACh through. |
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8 |
This causes the channel to open. |
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9 |
When enough sodium channels open, depolarising the membrane and creating a new action potential. |
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10 |
The enzyme acetylcholinesterase (attached to the postsynaptic membrane) breaks down ACh. Much of the choline is absorbed through the presynaptic membrane and remade into ACh. ATP REQUIRED. |