A 43-year-old man is brought in 18 hours after a meal that included home-bottled vegetables. Over the past six hours his eyelids have drooped, his vision has doubled and his voice has weakened, and his mouth is very dry. Both pupils measure 7 mm and react sluggishly to light. Shoulder abduction is weak against resistance. Sensation is normal throughout and he is fully alert and orientated.
Failure of which one of the following steps between the nerve impulse and muscle contraction best explains this man's findings 18 hours after the meal?
Keep going — a set of ten like this one, one at a time.
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