Question

If a concentrated NaCl solution is infused directly into the renal tubes of a healthy person, what is the most likely effect?

Answer 1

A - urine volume decreases because of decreased filtrate osmolarity
B - urine volume increases because of decreased filtrate osmolarity
C - urine volume increases because of increased filtrate volume
D - urine volume decreases because of increased filtrate osmolarity

solution is C but not exactly sure why

Answer 2

Please do not comment unless you are making a serious attempt at the problem.

Answer 3

I'm not completely sure, but here is my view as why:

If concentrated NaCl goes in the renal tubules, then the blood would be hypotonic to the filtrate. This would mean H2O would be secreted to the tubules to maintain tonicity and osmolarity. Therefore, the urine volume would definitely increase. I'm not sure what filtrate 'volume' has to do with this, I think osmolarity and concentration matter more.

Answer 4

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2709207/

I believe this might include the answer

Answer 5

Personally, I would've gone for an option like "Urine volume increases because of increased filtrate osmolarity" but there was no option like that so I suppose C was the only one left