Which of the following most accurately describes the actions of aldosterone?
A. Aldosterone increases Na+ secretion and K+ reabsorption in the cortical collecting ducts.
B. Aldosterone increases Na+ reabsorption and K+ secretion in the proximal tubule.
C. Aldosterone decreases Na+ reabsorption and K+ secretion in the cortical collecting ducts.
D. Aldosterone increases Na+ secretion and K+ reabsorption in the proximal tubule.
E. Aldosterone increases Na+ reabsorption and K+ secretion in the cortical collecting ducts.
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Question 2) Which of these would result in an increase in the osmolarity of urine?
A. increased levels of vasopressin in the plasma
B. increased levels of aldosterone in the plasma
C. decreased transport of Na+ and Cl- by the ascending limb of the loop of Henle
D. ingestion of a large volume of pure water
E. decreased urea permeability of the medullary collecting duct
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Question 3) Which of the following would be most likely to increase GFR?
A. sympathetic stimulation of afferent arteriolar smooth muscle
B. constricting efferent arterioles
C. a decrease in plasma volume
D. an increase in the concentration of plasma proteins
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Question 4) Which would result from ingesting a large amount of salt?
A. urine osmolarity would decrease
B. atrial natriuretic factor secretion would decrease
C. firing by hypothalamic osmoreceptors would decrease
D. secretion of atrial natriuretic factor would increase
E. secretion of vasopressin would decrease
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Question 5) Which of the following would cause a decrease in the excretion of Na+ and water?
A. increased hydrostatic pressure in the afferent renal arterioles
B. increased mean arterial blood pressure
C. increased atrial distension
D. decreased aldosterone secretion
E. decreased atrial natriuretic peptide secretion
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Question 6) In the presence of aldosterone, which nephron region reabsorbs the greatest fraction of the filtered Na+?
A. proximal tubule
B. macula densa
C. descending limb of the loop of Henle
D. distal convoluted tubule
E. cortical collecting duct
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Question 7) Which of the following organs is the main site of aldosterone secretion?
A. kidneys
B. adrenal glands
C. systemic and pulmonary blood vessels
D. liver
E. the atria of the heart
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Question 8) Which would occur as a result of a decrease in the total body content of Na+?
A. an increase in plasma volume, which induces an increase in GFR and Na+ reabsorption rate
B. a decrease in plasma volume, which induces an increase in GFR and Na+ reabsorption rate
C. an increase in plasma volume, which induces an increase in GFR and a decrease in Na+ reabsorption rate
D. a decrease in plasma volume, which induces a decrease in GFR and Na+ reabsorption rate
E. a decrease in plasma volume, which induces a decrease in GFR and an increase in Na+ reabsorption rate
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Question 9) What is the rate-limiting (regulated) step for stimulating the secretion of aldosterone?
A. conversion of angiotensin I to angiotensin II in the blood
B. secretion of angiotensinogen by the liver
C. conversion of angiotensinogen to angiotensin I in the blood
D. secretion of ACTH by the anterior pituitary
E. secretion of angiotensin II by the kidney
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Question 10) Which of the following statements regarding renal handling of Na+ is correct?
A. In the proximal tubule, Na+ is actively transported across the luminal membrane of the tubular epithelial cells.
B. Atrial natriuretic factor increases Na+ reabsorption.
C. In the absence of aldosterone, Na+ will be secreted by the cortical collecting ducts.
D. Na+ is actively reabsorbed in the ascending limb of the loop of Henle.
E. Without vasopressin, the collecting duct is impermeable to Na+.
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