Explain the process that occurs in neuromuscular junctions from when the action potential in the pre-synaptic knob to transmission in the next neurone (6 marks).
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The action potential in the pre-synaptic neurone causes calcium ion channels to open
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This causes calcium ions to diffuse into the neurone, down its concentration gradient
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This causes vesicles containing acetylcholine to fuse to the pre-synaptic membrane
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Acetylcholine is then released into the synaptic cleft
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Acetylcholine diffuses across the cleft and binds to sodium channels on the post-synaptic membrane, opening them
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Sodium ions diffuse into the post-synaptic membrane, causing depolarisation and triggering an action potential
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Acetylcholinesterase in the synaptic cleft binds to acetylcholine and delivers it back to the pre-synaptic knob to be recycled
HE
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