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+--- Thread: nbme 15 qqqq - stranger016 (/showthread.php?tid=764089)
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nbme 15 qqqq - stranger016 - ArchivalUser - 01-14-2014
Does anybody have an explanation for this question?
15) A healthy 25-year-old man participates in a study of muscle function. The electrophysiologic observations made on a muscle biopsy specimen are shown. Via iontophoresis, 1um acetylcholinen (Ach) was applied to the muscle surface. Extracellular Ca2+ concentration was decreased to prevent end-plate potentials from acting as a suprathreshold for muscle action potentials.
Normal muscle:
eep Amplitude meep Amplitude Response (in mV) to Ach
10 (in mV) 1 (in mV) 1 (1 uM)
[eep = end-plate potential; meep = miniature epp]
Based on these findings, which of the following electrophysiologic characteristics is expected in a muscle biopsy specimen from a patient with ACUTE BOTULISM?
eep Amplitude (in mV) meep Amplitude (inmV) Response (in mV) to Ach (1 um)
A) 1 0.5 0.5
B) 1 1 1
C) 2 0.2 0.2
D) 5 0.2 0.1
E) 15 1 1
can someone please explain why aaaa is wrongg
plzzz someone eplain
0 - ArchivalUser - 01-15-2014
anyone please
0 - ArchivalUser - 01-16-2014
no one???
0 - ArchivalUser - 01-16-2014
I think botulinum doesnit effect spontaneous depolarizations that's why it's unchanged
0 - ArchivalUser - 01-16-2014
botulism inhibits the release of ach so shouldn't response to ach be less than the normal muscle????
0 - ArchivalUser - 01-16-2014
In the absence of an action potential, acetylcholine vesicles spontaneously leak into the neuromuscular junction and cause very small depolarizations in the postsynaptic membrane. This small response is called a miniature end plate potential (MEPP) and is generated by one acetylcholine-containing vesicle. It represents the smallest possible depolarization which canb generated
0 - ArchivalUser - 01-16-2014
Botulinum will just effect the release of ach due a nerve impulse
0 - ArchivalUser - 01-16-2014
eep and meep both will have reduced values,also there will be no response.If it is a repetitive stimulation, there will be some postsynaptic response.
0 - ArchivalUser - 01-16-2014
ohhhh got it
thanx rainbow28 and dochtorc
0 - ArchivalUser - 01-16-2014
A seems appropriate?