Respuesta :
When a nerve impulse reaches the end of an axon of a neuromuscular junction, calcium flows into the synaptic knob.
In a neuromuscular junction, there are three parts. They are the presynaptic terminal or synaptic knob, the synaptic cleft and the postsynaptic terminal. The calcium ions will work in the synaptic knob when the nerve impulse arrives.
Once that the nerve impulse reaches the end of the axon, it will affect the presynaptic terminal. In there, it causes the opening of voltage-gated calcium channels. As a result:
- Calcium flows into the presynaptic terminal.
- The calcium makes the vesicles (with neurotransmitters) descend and fuse with the terminal membrane to release the neurotransmitters to the synaptic cleft.
In conclusion, the nerve impulse causes the opening of voltage-gated calcium channels, and calcium flows into the synaptic knob.
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https://brainly.com/question/6602127
