6 steps of neuromuscular junction
5
ACh binding opens ion channels that allows simultaneous passage of Na+ into muscle fibers and K+ out of muscle fibers. More Na+ ions enter than K+ ions exit, which produces change in membrane potential called "end plate potential"
4
ACh diffuses across synaptic cleft and binds to its receptors on sarcolemma
6
ACh effects are terminated by its breakdown in synaptic cleft by acetylcholinesterase and diffusion away from junction
3
Ca2+ entry causes ACh to be released by exocytosis
1
action potential (AP) comes from central nervous system and arrives at axon terminal of motor neuron
2
voltage-gated Ca2+ channels open. Ca2+ enters axon, moving down electrochemical gradient