Step I MEPP&EPP

[Miracoli]

55-year-old woman visits her physician because of double vision, eyelid droop, difficulty chewing
and swallowing, and general weakness in her limbs. All these symptoms are made worse with exercise
and occur more frequently late in the day. In this pt you are most likely to find the EPP(end plate potential)& MEPP(miniature end plate potential) to be:
__________________EPP______________________________________MEPP____
A)_______________normal____________________________________normal___
B)_______________normal____________________________________increase___
C)_______________increase____________________________________normal___
D)_______________decrease____________________________________normal___
E)_______________normal_____________________________________decrease___
F)_______________decrease___________________________________decrease___
G)_______________decrease___________________________________increase___

 

[alicealicealice]

F
Both decreased, because the amplitude of both depends on the amount of functioning receptors.

 

[BlueArc]

F or maybe D?

 

[surgok]

F?

 

[Miracoli]

FF is correct
pt has myathenia gravis
- Myasthenia Gravis(MG)-- antibodies directed against the AChR- -> fewer AChRs are opened by each quantum of ACh release, and the amplitude of the MEPP is reduced. Fewer MEPPs are generated and the EPP is lower.

Thank you for participation
For more explanation about membrane potential check here
http://www.usmleforum.com/files/forum/2014/1/767949.php