NBME 7 Question.. Confusing, Please Help - saadke

[ArchivalUser]

65 year old man comes in with SOB for 12 hours. Crackles on chest ausculation. Pitting Edema etc.. basically CHF..

Which of the following changed in renal function is most likely?
a) decrease CL- reabsorption
b) decrease Na reabsorption
c) increased GFR
d) increase K excretion
e) increase renal blood flow

So obviously renin-AT system will be activated. So the answer is between C and D. The right answer is D, but why can't it be c as well? AT increase will contract the efferent arteriole increasing the GFR. I don't understand why that can't be the answer!!!

[ArchivalUser]

i think since there is hypovolemia due to transudation in chf.....the inc in gfr caused by angiotensin is not enuf to raise gfr that means it doesnt compensate properly for the drop in gfr due to hypovolemia.....a similar quesn is present in uw whr a pt comes wid sever nausea vommiting diarrhea and has inc ff but gfr still decreases...refer that quesn further from uw if u still have doubt...

[ArchivalUser]

Can u please help me understand Q 15 block 4 NBME 7

[ArchivalUser]

hiii jyothi....the quesn is a bit tricky here...we shud read the question carefully....all he meant was the mechanism by which adenylyl cyclase is activated...and that is by GTP because we are talking about G protein coupled receptor system with 7 serpentine transmembrane domains linked to intracellular G-protin that activates adenylyl cyclase which inturn inc. cAMP....very tricky quesn...i too got it wrong on my exam
i hope u got it

[ArchivalUser]

hi jyothi...how much did u scre on nbme7 and wen ru givin exam??? whats ur study plan till the exam?? i gave my nbme7 las week and got low--205....rite nw im doin fa....my exams in early march...wht abt u???