What is a neuromuscular junction

Action potential arrives at the pre-synaptic knob. This causes the ___CA2+__ ion channels to ______OPEN_______. This causes ___________ containing acetylcholine to fuse with the _______PRE SYPAPTIC MEMBRANE__________________. Acetylcholine is released. Acetylcholine ___DIFFUSES___________ across the ___SYNAPTIC CLEFT___________ and binds to the ____RECEPTORS_________ on the _________________. This stimulates ___NA+_____ ion channels to open. _NA+_________ ions diffuse ___IN____ causing depolarisation. If the _____THRESHOLD________ is passed, action potentials will occur in the muscle membrane (sarcolemma). The action potentials move along the muscle membrane deep within the muscle. This stimulates calcium ions to diffuse out of the sarcoplasmic reticulum. Calcium ions causes the muscle contraction (remember the 7 steps of muscle contraction).