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Advanced urinary system quiz

Clinical Application #1: Inulin and Measuring the Glomerular Filtration Rate

Inulin is a compound produced by plants such as artichokes, onions and garlic which does not get secreted nor reabsorbed along the nephron. Because of this special characteristic we can say that the amount of inulin excreted in the urine per minute is equal to the amount that is filtered by the glomerulus per minute (the glomerular filtration rate).

Doctors inject inulin directly into the blood plasma to determine the glomerular filtration rate. Two equations are utilized to determine the glomerular filtration rate. Remember, the inulin excreted per minute and inulin filtered per minute are equivalent to one another since no inulin gets secreted nor absorbed along the nephron.

Inulin excreted per minute = V \cdot U

Where $V$ ‍ = rate of urine formation (mL/min)
Where $U$ ‍ = inulin concentration in urine (mg/mL)

Inulin filtered per minute = G F R \cdot P

Where $P$ ‍ = inulin concentration in plasma (mg/mL)
Where $G F R$ ‍ = glomerular filtration rate (mL/min)

Based on the information above, determine the glomerular filtration rate of a patient with an inulin concentration in the urine of 15 mg per mL; an inulin concentration in the plasma of 0.25 mg per mL; and a rate of urine formation of 2 mL per minute.

The patient has a glomerular filtration rate of

mL/min

Health and medicine

Course: Health and medicine > Unit 1

Problem

Clinical Application #1: Inulin and Measuring the Glomerular Filtration Rate