Biomedical Engineering: Bridging Medicine and Technology 1st Edition by Veronique Tran,Mark Saltzman

Exercise 11

Assume that the plasma concentration of substance X is 2 mg/mL and that it
is freely filtered in the glomerulus.
a. If the GFR is 125 mL/min, what is the rate of substance X flow into the
renal tubules?
b. If the maximum tubular reabsorption rate for substance X is 200 mg/min,
how much X will be reabsorbed and how much will be excreted?
c. Why do many compounds-including substance X in this example-have
a maximum tubular reabsorption rate (i.e., what determines the maximum
reabsorption rate for a compound)?