This sample test contains 25 multiple choice questions and answers on renal physiology. The answer key is provided at the end. If you do not understand a question or why the answer provided is correct, contact Dr. Walker at 220-7627 or email rlwalker@acs.ucalgary.ca
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1. The peritubular capillaries
a. supply nutrients and O2 to the tubular cells.
b. take up the substances that are reabsorbed by the tubules.
c. supply substances that are secreted by the tubules.
d. All of the above are correct.
e. None of the above is correct.
2. The glomerular filtrate as it enters Bowman's capsule
a. is a protein-free plasma.
b. is identical in composition to urine.
c. contains only substances that are not needed by the body.
d. is formed as a result of active forces.
e. is formed at a constant rate under all circumstances.
3. What establishes the colloidal osmotic pressure to determine a net
filtration pressure?
a. plasma proteins
b. glucose
c. sodium
d. urea
e. calcium
4. The filtration coefficient
a. is a measure of the surface area and permeability of the glomerular
membrane.
b. is a constant value.
c. can be varied by contraction of the podocytes and mesangial cells.
d. Both a and b above are correct.
e. Both a and c above are correct.
5. The glomerular capillary blood pressure in the nephron is 78 mm Hg. The
Bowman's capsular hydrostatic pressure is 24 mm Hg. The colloidal
osmotic pressure is 18 mm Hg. The net filtration pressure is __________
mm Hg.
a. 18
b. 26
c. 36
d. 42
e. 78
6. Which of the following forces oppose glomerular filtration?
a. blood-colloid osmotic pressure
b. Bowman's capsule hydrostatic pressure
c. glomerular-capillary blood pressure
d. Both a and b above are correct.
e. Both b and c above are correct.
7. Which of the following statements concerning the process of glomerular
filtration is correct?
a. Bowman's capsule hydrostatic pressure opposes filtration.
b. The glomerular filtration rate is limited by a Tm.
c. All of the plasma that enters the glomerulus is filtered.
d. Two of the above are correct.
e. All of the above are correct.
8. Which of the following factors would decrease the GFR?
a. a fall in plasma protein concentration
b. an obstruction such as a kidney stone in the tubular system, which
increases Bowman's capsule hydrostatic pressure
c. vasodilation of the afferent arterioles
d. Two of the above are correct.
e. All of the above would increase the GFR.
9. Which of the following is involved in autoregulation of the GFR?
a. a myogenic mechanism in which the afferent arteriole automatically
constricts when it is stretched
b. a tubulo-glomerular feedback mechanism in which vasoactive
chemicals released from the juxtaglomerular apparatus bring about
afferent arteriolar vasoconstriction
c. sympathetically induced vasoconstriction of the afferent arterioles
d. Both a and b above are correct.
e. All of the above are correct.
10. When arterial blood pressure is elevated above normal, which of the
following compensatory changes in renal function occur as a result of
the baroreceptor reflex?
a. Afferent arteriolar vasoconstriction
b. Afferent arteriolar vasodilation
c. Reduction in GFR
d. Both a and c above are correct.
e. Both b and c above are correct.
11. Which of the following statements regarding tubular reabsorption is
incorrect? Tubular reabsorption
a. refers to the movement of a substance from the tubular fluid to the
peritubular capillary blood.
b. is important for the conservation of substances important to the
body, such as Na+, Cl-, glucose, and amino acids.
c. can occur by active or passive transport mechanisms.
d. involves the process of transepithelial transport.
e. takes place only in the proximal tubule.
12. The Na+-K+ ATPase transport system that plays a pivotal role in much of
tubular reabsorption is located in the
a. luminal membrane of tubular cells.
b. basolateral membrane of tubular cells.
c. podocytes.
d. glomerular capillary membrane.
e. basement membrane.
13. Tubular maximum (Tm)
a. is the maximum amount of a substance that the tubular cells can
actively transport within a given time period.
b. is the maximum rate at which a substance is filtered at the
glomerulus.
c. occurs when the membrane carrier becomes saturated.
d. Both a and c above are correct.
e. Both b and c above are correct.
14. The renal threshold is
a. the maximum amount of a particular substance that can be excreted
in the urine per unit of time.
b. the maximum amount of a particular substance that the tubular cells
are capable of actively reabsorbing per unit of time.
c. the plasma concentration of a particular substance at which its Tm
is reached and the substance first appears in the urine.
d. the maximum amount of waste products that can be concentrated in
the urine per unit of time.
e. the maximum amount of water that can be osmotically absorbed across
the tubules per unit of time.
15. Given the following data for substance X (GFR = 125 ml/min, Tm = 125
mg/min, at a plasma concentration of 200 mg/100 ml), how much of
substance X is filtered, reabsorbed, and excreted?
a. 200 mg/min filtered, 125 mg/min reabsorbed, 75 mg/min excreted
b. 250 mg/min filtered, 125 mg/min reabsorbed, 125 mg/min excreted
c. 125 mg/min filtered, 125 mg/min reabsorbed, 0 mg/min excreted
d. 250 mg/min filtered, 200 mg/min reabsorbed, 50 mg/min excreted
e. None of the above is correct.
16. The juxtaglomerular apparatus
a. secretes renin in response to sodium depletion or plasma volume
reduction.
b. is a thickened region of specialized cells at a point where the
distal tubule comes into intimate contact with the afferent and
efferent arterioles of the same nephron.
c. is the site of Na+ reabsorption in the kidneys.
d. Both a and b above are correct.
e. All of the above are correct.
17. Aldosterone
a. stimulates Na+ reabsorption in the distal tubules.
b. is secreted by the juxtaglomerular apparatus.
c. stimulates K+ secretion in the distal tubule.
d. Both a and b above are correct.
e. Both a and c above are correct.
18. The greatest percentage of Na+ reabsorption takes place in the
a. proximal tubule.
b. loop of Henle.
c. distal tubule.
d. collecting tubule.
e. renal pelvis.
19. Sodium reabsorption in the distal portions of the nephron is stimulated
by
a. atrial natriuretic peptide.
b. vasopressin.
c. angiotensin II.
d. aldosterone.
e. renin.
20. Which of the following is not attributable to atrial natriuretic
peptide (ANP)?
a. ANP is released from the cardiac atria when the ECF volume is
reduced.
b. ANP inhibits Na+ reabsorption in the distal parts of the nephron.
c. ANP inhibits renin secretion by the kidneys.
d. ANP inhibits aldosterone secretion by the adrenal cortex.
e. ANP inhibits sympathetic nervous activity to the heart and blood
vessels.
21. Water reabsorption
a. occurs passively by osmosis in the proximal tubule.
b. is under the control of vasopressin in the distal and collecting
tubules.
c. occurs by active transport in the distal and collecting tubules.
d. Both a and b above are correct.
e. All of the above are correct.
22. Which of the following stimulates aldosterone secretion?
a. An increase in plasma K+.
b. A decrease in plasma K+.
c. Activation of the renin-angiotensin pathway.
d. Both a and c above are correct.
e. Both b and c above are correct.
23. The __________ establish the medullary vertical osmotic gradient by
means of countercurrent multiplication.
a. loops of Henle of juxtamedullary nephrons
b. loops of Henle of cortical nephrons
c. vasa recta of juxtamedullary nephrons
d. vasa recta of cortical nephrons
e. vasopressin-secreting cells
24. The ascending limb of the loop of Henle of a juxtamedullary nephron
a. actively transports NaCl out of the lumen into the interstitial
fluid.
b. is highly permeable to H2O.
c. is always impermeable to H2O.
d. Both a and b above are correct.
e. Both a and c above are correct.
25. Vasopressin secretion
a. induces the kidneys to produce a small volume of concentrated
urine.
b. is stimulated when the body fluids are hypertonic.
c. is inhibited when the arterial blood pressure is dangerously low.
d. Both a and b above are correct.
e. All of the above are correct.
Answer Key
1. d
2. a
3. a
4. e
5. c
6. d
7. a
8. b
9. d
10. b
11. e
12. b
13. d
14. c
15. b
16. d
17. e
18. a
19. d
20. a
21. d
22. d
23. a
24. e
25. d