150.A 33-year-old woman is referred to the neurology clinic complaining
of weakness of the eye muscles which began 2 months ago. Subsequently
she has had diplopia and increasing difficulty in swallowing. Her speech is
slurred and she says that she has difficulty clearly enunciating and pro-
nouncing many words. The physical exam reveals bilateral ptosis and an
unstable, waddling gait, and some shortness of breath. Laboratory and
diagnostic tests reveal a positive edrophonium chloride (tensilon) test and
autoantibodies to the acetylcholine receptor. On the accompanying trans-
mission electron micrograph which region is most affected in this disease?
Nervous System 239a. A
b. B
c. C
d. D
e. E
(Micrograph courtesy of Dr. Michael J.Werle.)