5. Physiology

Renal Function — Quiz

Test your understanding of renal function with 5 practice questions.

Practice Questions

Question 1

Given a glomerular filtration rate of $125\,\mathrm{mL/min}$ and a tubular maximum (Tm) for glucose of $375\,\mathrm{mg/min}$, at what plasma glucose concentration does glycosuria begin (threshold)?

Question 2

A patient has plasma [Na$^+$] = 140 mEq/L, urine [Na$^+$] = 70 mEq/L, urine flow = 1.0 mL/min, and GFR = 120 mL/min. What is the fractional excretion of sodium (FE$_{Na}$)?

Question 3

Plasma PAH concentration is 0.05 mg/mL, urine PAH concentration is 50 mg/mL, and urine flow rate is 1.2 mL/min. What is the effective renal plasma flow (RPF) estimated by PAH clearance?

Question 4

Which feature of the vasa recta is essential for preserving the renal medullary osmotic gradient?

Question 5

Loop diuretic administration inhibits NKCC2 in the thick ascending limb. What is the resulting effect on the medullary osmotic gradient and maximal urine concentrating ability?