Neurotransmitter of neuromuscular junction

Question

What do you mean by the neurotransmitter of neuromuscular junction? Explain, how the nervous system triggers the muscle contraction?

Answer 1

Nervous cells which result in contraction of muscles are motor neurons. The neurotransmitter of motor neurons is known as acetylcholine. Whenever a motor neuron gets excited the depolarizing current flows all along the membrane of its axon until reaching the synapse at neuromuscular junction: the neural impulse passage zone between the sarcolemma and the axon extremity. Near to the axonal extremity the depolarization permits entrance of the calcium ions to the axon. The calcium ions stimulate neuron in order to release acetylcholine in synapse. Then acetylcholine binds to the special receptors in outer surface of sarcolemma, permeability of this membrane is changed and action potential gets created. Depolarization is conduced all along the sarcolemma to sarcoplasmic reticulum which therefore releases calcium ions for the contraction of the sarcomere.