526
Chapter 14
4. Which of the following contributes directly to the generation of
a hypertonic medullary interstitium in the kidney?
a. active sodium transport in the descending limb of Henle’s
loop
b. active water reabsorption in the ascending limb of Henle’s loop
c. active sodium reabsorption in the distal convoluted tubule
d. water reabsorption in the cortical collecting duct
e. secretion of urea into Henle’s loop
5. An increase in renin is caused by
a. a decrease in sodium intake.
b. a decrease in renal sympathetic nerve activity.
c. an increase in blood pressure in the renal artery.
d. an aldosterone-secreting adrenal tumor.
e. essential hypertension.
6. An increase in parathyroid hormone will
a. increase plasma 25(OH) D.
b. decrease plasma 1,25-(OH)
2
D.
c. decrease calcium excretion.
d. increase phosphate reabsorption.
e. increase calcium reabsorption in the proximal tubule.
7. Which of the following is a component of the renal response to
metabolic acidosis?
a. reabsorption of hydrogen ions
b. secretion of bicarbonate into the tubular lumen
c. secretion of ammonium into the tubular lumen
d. secretion of glutamine into the interstitial fl
uid
e. carbonic anhydrase-mediated production of HPO
4
2–
8. Which of the following is consistent with respiratory alkalosis?
a. an increase in alveolar ventilation during mild exercise
b. hyperventilation
c. an increase in plasma bicarbonate
d. an increase in arterial CO
2
e. urine pH < 5.0
9. Which is true about the difference between cortical and
juxtamedullary nephrons?
a. Most nephrons are juxtamedullary.
b. The efferent arterioles of cortical nephrons give rise to most
of the vasa recta.
c. The afferent arterioles of the juxtamedullary nephrons give
rise to most of the vasa recta.
d. All cortical nephrons have a loop of Henle.
e. Juxtamedullary nephrons generate a hyperosmotic medullary
interstitium.
10. Which of the following is consistent with untreated chronic
renal failure?
a. proteinuria
b. hypokalemia
c. increased plasma 1,25-(OH)
2
D
d. increased plasma erythropoeitin
e. increased plasma bicarbonate
Chapter 14 Quantitative and Thought Questions
(Answers appear in Appendix A.)
1. Substance T is present in the urine. Does this prove that it is
fi lterable at the glomerulus?
2. Substance V is not normally present in the urine. Does this
prove that it is neither fi ltered nor secreted?
3. The concentration of glucose in plasma is 100 mg/100 ml,
and the GFR is 125 ml/min. How much glucose is fi ltered per
minute?
4. A person is excreting abnormally large amounts of a particular
amino acid. Just from the theoretical description of
T
m
-limited
reabsorptive mechanisms in the text, list several possible causes.
5. The concentration of urea in urine is always much higher
than the concentration in plasma. Does this mean that urea is
secreted?
6. If a person takes a drug that blocks the reabsorption of sodium,
what will happen to the reabsorption of water, urea, chloride,
glucose, and amino acids and to the secretion of hydrogen ions?
7. Compare the changes in GFR and renin secretion occurring in
response to a moderate hemorrhage in two individuals—one
taking a drug that blocks the sympathetic nerves to the kidneys
and the other not taking such a drug.
8. If a person is taking a drug that completely inhibits angiotensin-
converting enzyme, what will happen to aldosterone secretion
when the person goes on a low-sodium diet?
9. In the steady state, is the amount of sodium chloride excreted
daily in the urine of a normal person ingesting 12 g of sodium
chloride per day: (a) 12 g/day or (b) less than 12 g/day?
Explain.
10. A young woman who has suffered a head injury seems to have
recovered but is thirsty all the time. What do you think might
be the cause?
11. A patient has a tumor in the adrenal cortex that continuously
secretes large amounts of aldosterone. What is this condition
called, and what effects does this have on the total amount of
sodium and potassium in her body?
12. A person is taking a drug that inhibits the tubular secretion of
hydrogen ions. What effect does this drug have on the body’s
balance of sodium, water, and hydrogen ions?
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