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So, the EPPs seem to be whole number multiples of some unit MEPP. The vesicle
theory of signal transmission across the neuromuscular junction is consistent
with the quantal nature of EPPs. Here's the picture:
There will be thousands of little vesicles each filled with a dose of acetylcholine (ACh). Simply put, the effect of the incoming impulse on the vesicles is to cause them to fuse to the membrane leading to the release of their contents across the membrane. The ACh then promotes an appropriate reaction in the muscle. Hence the transmitted signal will come in packets, each packet or quantal response corresponding to a vesicle releasing its ACh. We might then ask if the behavior of any given vesicle is independent of the others. And is the probability that a given vesicle will fuse and release the same for all the vesicles? If so, then mathematics predicts a certain statistical behavior, a distribution of responses that, if observed, would tend to corroborate the notion that the vesicles are independent and the probabilities the same. |