Human kidney discussion

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16. A tumor in the adrenal cortex can lead to the continuous secretion of large amounts of aldosterone. What effect would that have on the levels ofNa+ and K+?

17. What result do you expect from a mutation in aquaporin-2 that makes it insensitive to ADH (so that the level of water channels is low)?

Additional questions to think about later
18. Substance T is present in the urine. Does this prove that it is filtered at the glomerulus?

19. Substance V is a small molecule present in plasma that is not normally present in the
urine; does this prove that it is not filtered?

20. The concentration of urea in urine is always much higher than the concentration in
plasma. Does this mean that urea is secreted?

21. In the steady state, is the amount of NaCl in the urine of a person ingesting 12 g of
sodium/day less or equal to 12 g/day?

22. The glomerular filtration rate(GFR) is the volume of fluid that is filtered (transfered
from the glomerulus to Bowman's capsule) per minute. It can be estimated from the
excretion of substance (such as inulin) that are filtered, but not reabsorbed. (FYI, this
number is also reported as clearance, as in the volume of blood that the substance has
been clearedfrom.)

GFR = (conc. inulin in urine) x volume of urine
conc. inulin inplasma

A normal subject is producing 1 ml urine/min with a concentration of inulin of 0.48
mg/ml. The concentration of inulin in the blood is 0.004 mg/ml. What is the GFR?

23. Why do patients taking diuretics that block Na+ resorption in the ascending loop of
Henle need K+ supplements?


		16. A tumor in the adrenal cortex can lead to the continuous secretion of large amounts of aldosterone. What effect would that have on the levels ofNa+ and K+?
		17. What result do you expect from a mutation in aquaporin-2 that makes it insensitive to ADH (so that the level of water channels is low)?
		Additional questions to think about later 18. Substance T is present in the urine. Does this prove that it is filtered at the glomerulus? 19. Substance V is a small molecule present in plasma that is not normally present in the urine; does this prove that it is not filtered? 20. The concentration of urea in urine is always much higher than the concentration in plasma. Does this mean that urea is secreted? 21. In the steady state, is the amount of NaCl in the urine of a person ingesting 12 g of sodium/day less or equal to 12 g/day?
		22. The glomerular filtration rate(GFR) is the volume of fluid that is filtered (transfered from the glomerulus to Bowman's capsule) per minute. It can be estimated from the excretion of substance (such as inulin) that are filtered, but not reabsorbed. (FYI, this number is also reported as clearance, as in the volume of blood that the substance has been clearedfrom.) GFR = (conc. inulin in urine) x volume of urine conc. inulin inplasma A normal subject is producing 1 ml urine/min with a concentration of inulin of 0.48 mg/ml. The concentration of inulin in the blood is 0.004 mg/ml. What is the GFR?
		23. Why do patients taking diuretics that block Na+ resorption in the ascending loop of Henle need K+ supplements?