the membrane. ACh is released normally, but its effect on the postsynaptic
membrane is reduced. The postjunctional membrane is less sensitive to
applied ACh, and the probability that any nerve impulse will cause a mus-
cle action potential is reduced. The edrophonium chloride (tensilon) test
uses a rapid acting and degrading acetylcholine esterase inhibitor. It causes
neuromuscular transmission to be increased in the patient. The physician
injects the tensilon and then looks for rapid relief of the symptoms, par-
ticularly the eyelids and the diplopia. Other structures labeled in the elec-
tron micrograph are: A =nucleus, B =mitochondria, C =myofilaments,
and D =nerve terminal.
250 Anatomy, Histology, and Cell Biology