Neuromuscular Junction

What is the name of the neurotransmitter released at the neuromuscular junction?

• Dopamine

• Acetylcholine

• Norepinephrine

• Serotonin

Which structure releases calcium ions (Ca²⁺) into the sarcoplasm to initiate muscle contraction?​

​ ​ (a)  

• Sarcoplasmic reticulum
• Mitochondria
• T-tubules
• Myofibrils

What happens when acetylcholine binds to its receptor on the sarcolemma (muscle fiber membrane)?

• Sarcolemma becomes impermeable to ions

• Ligand-gated ion channels open causing depolarization

• Calcium ions are pumped into synaptic cleft

• Potassium ion channels close

Which ion triggers the synaptic vesicles to fuse with the presynaptic membrane in the neuromuscular junction?

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