PRACTICE QUESTIONS

1. In carnivores, the usual role of the kidney in maintaining acid-base homeostasis is to:

a. Secrete excess bicarbonate.

b. Secrete excess ammonia.

c. Secrete excess acid.

d. Secrete excess carbon dioxide.

e. Secrete excess phosphate buffer.

2. The bulk of acid secretion (bicarbonate reabsorption) is accomplished by which renal tubule segment?

a. Proximal tubule

b. Thin limbs of Henles loop

c. Thick ascending limb of Henle’s loop

d. Distal convoluted tubule

e. Collecting duct

4. Which of the following statements regarding mechanisms of acid-base regulation by the collecting duct is false?

a. The cortical collecting duct responds to acidosis by increasing the net rate of acid secretion.

b. The cortical collecting duct responds to alkalosis with net bicarbonate secretion.

c. Proton and bicarbonate transport in the collecting duct are only slightly altered in response to systemic acid-base disturbances.

d. The collecting duct determines the ultimate pH of the urine.

e. The intercalated cells are largely responsible for acid secretion by the collecting duct.

5. Which of the following statements is correct?

a. Aldosterone affects acid excretion by enhancing bicarbonate secretion by the proximal tubule.

b. Aldosterone affects acid excretion by enhancing proton secretion by the collecting duct.

c. Aldosterone affects acid excretion by inhibiting bicarbonate secretion by the collecting duct.

d. Aldosterone affects acid excretion by inhibiting bicarbonate reabsorption by the proximal tubule.

e. Aldosterone has no effect on acid excretion.