Question

Explain the transmission of nerves imples in the neuromuscular function

Answer 1

1. As an action potential arrives at the presynaptic terminal, a depolarisation of the motor neuron membrane occurs which initiates the opening of voltage-gated Ca2+ ion channels - releasing Ca2+ into the neuron to stimulate the release of vesicles containing Acetylcholine.
2. Acetylcholine acts as the neurotransmitter in this context. These vesicles can then bind, and dock to the membrane of the presynaptic neuron with the assistance of SNARE proteins, releasing Acetylcholine into the synaptic cleft.
3. Acetylcholine is then able to diffuse across the synaptic cleft, eventually binding to nicotinic Acetylcholine receptors on the motor end-plate (the post-synaptic membrane).
4. This binding causes a further opening of voltage-gated Na+ ion channels, which cause an influx of Na+, depolarising the membrane.
5. An action potential is then able to be propagated along the sarcolemma as further Na+ ion channels are opened.

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