Instructions: In this Section, occasionally there are questions with multiple correct answers.
Read all options!
1. The ‘gold standard’ for estimation of glomerular filtration rate is the estimation of urinary clearance of:
A. inulin
B. creatinine
C. urea
D. mannitol
E. glucose
F. para-amino hippuric acid
2. In clinical practice, the urinary clearance of which substance is most frequently estimated as a surrogate of GFR?
A. Inulin
B. Creatinine
C. Urea
D. Mannitol
3. Which of the following substances should not
be used to measure GFR?
A. Inulin
B. Creatinine
C. Iothalamate
D. Glucose
E. Phenol red
4. The term filtration fraction is used to refer to:
A. RPF / GFR
B. GFR / RPF
C. RPF GFR
5. What fraction of renal plasma flow is normally filtered in the glomerular capillaries?
A. 0.1
B. 0.2
C. 0.3
D. 0.4
6. When mean arterial pressure is held constant, selective constriction of glomerular efferent arterioles:
A. increases GFR
B. decreases filtration fraction
C. decreases renal plasma flow
7. Mesangial cells are similar to:
A. pericytes
B. fibrocytes
C. mast cells
D. ependymal cells
8. In humans, what percentage of nephrons has long loops of Henle?
A. 5
B. 15
C. 25
D. 85
9. The macula densa is located in the:
A. juxtaglomerular cells
B. extraglomerular mesangium
C. beginning of distal tubule
D. peritubular capillaries
10. The kidneys do not synthesize or secrete:
A. calcitriol
B. rennin
C. erythropoietin
D. PGE2
11. The brush border on the luminal membrane is most extensive in cells of the:
A. PCT
B. loop of Henle
C. DCT
D. collecting duct
12. Which of the following increases renal cortical blood flow?
A. Prostaglandin E2
B. Norepinephrine
C. Angiotensin II
D. Vasopressin
13. In the kidneys, type I medullary interstitial cells secrete:
A. renin
B. PGE2
C. aquaporins
D. aldosterone
14. The para-aminohippuric acid (PAH) clearance of a 56-year-old male with sustained elevations of blood urea nitrogen, creatinine and potassium was estimated to be 100 ml/min. His PCV is 20. Assuming renal extraction of PAH to be complete, his renal blood flow is approximately:
A. 25 ml/min
B. 125 ml/min
C. 250 ml/min
D. 600 ml/min
15. The renal plasma flow (RPF) of a patient was to be estimated through the measurement of para- amino hippuric acid (PAH) clearance. The technician observed the procedures correctly but due to an error in weighing inadvertently used thrice the recommended dose of PAH. The RPF estimated thus is likely to be:
A. falsely high
B. falsely low
C. high or low depending on GFR
D. correct and is unaffected by the overdose of PAH
16. If the glomerular capillary hydrostatic pressure, osmotic pressure of plasma proteins, hydrostatic pressure in the Bowman’s space and oncotic pressure in the interstitium are respectively 40, 25, 5, and 0 mm Hg respectively, what is the net pressure driving filtration of fluid into the Bowman’s space?
A. 10 mm Hg
B. 15 mm Hg
C. 20 mm Hg
D. 25 mm Hg
17. In an experimental animal with acutely induced bilateral obstruction of ureters, glomerular filtration rate declines within 30 min of ligation of ureters primarily due to a/an:
A. increase in filtration fraction
B. increase in renal plasma flow
C. increase in hydrostatic pressure in Bowman’s space
D. decrease in glomerular capillary permeability
18. Which of the following substances is cleared the most by the kidneys?
A. Inulin
B. PAH
C. Creatinine
D. Urea
19. Which of the following substances normally has a “clearance ratio” of about 1.2?
A. Inulin
B. Creatinine
C. Urea
D. PAH
20. Which of the following substances has a clearance ratio close to 1?
A. Creatinine
B. Mannitol
C. Urea
D. Glucose
21. Arrange the following substances in the descending order of their clearance. [Cr: creatinine; PAH: para-aminohippuric acid]
A. PAH > Inulin > Urea > Cr > Glucose
B. Inulin > PAH > Cr > Urea > Glucose
C. PAH > Cr > Inulin > Urea > Glucose
22. The tubular transport maximum for glucose (Tmax for glucose) in a healthy young man is about:
A. 100 mg/min
B. 225 mg/min
C. 375 mg/min
D. 500 mg/min
23. If urine [Na] = 100 mM, plasma [Na] = 140 mM, urine [Cr] = 100 mg/dL, serum [Cr] = 1.4 mg/dL, and urine flow rate = 2 ml/min, then, fractional excretion of sodium (FENa) is approximately:
A. 0.1%
B. 0.5%
C. 1%
D. 2%
24. In a healthy individual with a normal renal plasma flow, in which segment of the nephron would the concentration of PAH be the least?
A. Proximal convoluted tubule
B. Thin descending limb of loop of Henle
C. Thick ascending limb of loop of Henle
D. Cortical collecting duct
25. Autoregulation of GFR is achieved through changes in:
A. renal perfusion pressure
B. renal blood flow
C. glomerular afferent arteriolar resistance
D. glomerular efferent arteriolar resistance
26. In a healthy adult human with a resting BP averaging about 110/70 mm Hg who is not on any medication, the earliest MAP at which renal autoregulation of GFR is overwhelmed is when mean arterial pressure falls below:
A. 30 mm Hg
B. 50 mm Hg
C. 70 mm Hg
D. 90 mm Hg
27. In an individual with normal renal function but with fluctuations in glomerular filtration rate (GFR) of 10% around a mean GFR of 100 ml/min, fractional reabsorption of Na and Cl in which segment of the nephron is relatively constant?
A. Proximal tubule
B. Thick ascending limb of loop of Henle
C. Distal convoluted tubule
D. Cortical collecting duct
28. The rate-limiting step in the biosynthesis of angiotensin II is the secretion of:
A. renin
B. angiotensinogen
C. angiotensin I
D. angiotensin II
29. Renin in the circulation originates mainly from:
A. macula densa
B. juxtaglomerular cells
C. type I medullary interstitial cells
D. peritubular capillaries
30. The substrate for renin is:
A. angiotensinogen
B. angiotensin I
C. angiotensin II
D. bradykinin
31. Angiotensin converting enzyme is a / an:
A. dipeptidyl carboxypeptidase
B. aminopeptidase
C. aspartyl protease
32. Physiologically, important stimulators of aldosterone production by the zona glomerulosa cells include (tick all that apply):
A. a rise in plasma [K+]
B. angiotensin II
C. angiotensin III
33. Several hormones regulate tubular reabsorption of water and electrolytes at different sites in the nephron. Which of the following combinations is/are correct?
A. Angiotensin II acts in the DCT
B. Aldosterone acts in the collecting ducts
C. ADH acts in the PT
D. ANP acts in the loop of Henle
34. The actions of aldosterone are antagonized by:
A. angiotensin III
B. arginine vasopressin (AVP)
C. ANP
35. Which hormone directly induces proton secretion by alpha-intercalated cells in the collecting ducts?
A. Aldosterone
B. Atrial natriuretic peptide
C. Vasopressin
D. Parathyroid hormone
36. All about angiotensins:Which of the following are true and which are false?
1. Angiotensin converting enzyme is a dipeptidyl carboxypeptidase.
2. ANG II is a much more potent vasopressor compared to norepinephrine.
3. ANG III is a more potent pressor than ANG II.
4. ANG II stimulates aldosterone release from adrenal cortex.
5. ANG II inhibits ADH release.
6. ANG II has a dipsogenic effect (i.e., induces hirst)
7. ANG II causes mesangial cells to contract.
8. ANG II facilitates norepinephrine release from postganglionic sympathetic neurons.
9. ANG II has a greater constrictor effect upon glomerular afferent arterioles.
10. ANG II reduces renal plasma flow.
11. When GFR is reduced, ANG II’s actions enable a decrease in filtration fraction.
12. ANG II increases Na and H2O reabsorption by a direct action on PT.
13. ANG II increases Na and Cl reabsorption by the DCT.
14. ANG II increases Na reabsorption by P cells in the collecting duct.
15. ANG II directly stimulates potassium secretion by P cells in the collecting duct.
16. ANG II plays an important role in cardiac remodeling after a myocardial infarction.
37. Chronic licorice ingestion is characterized by:
A. low blood pressure
B. hyperkalemia
C. metabolic acidosis
D. a decrease in plasma renin activity
38. In the nephron, glucose reabsorption occurs mainly in the:
A. proximal tubule
B. loop of Henle
C. distal convoluted tubule
D. collecting duct
39. The following data were obtained on a patient: Creatinine clearance = 125 ml/min; plasma [glucose] = 400 mg/dL. If the tubular maximum for glucose were 350 mg/min, what would the glucose excretion rate be?
A. 50 mg/min
B. 100 mg/min
C. 150 mg/min
D. 200 mg/min
40. In the presence of vasopressin, most of the water filtered by the kidneys is reabsorbed in the:
A. proximal tubule
B. thin descending limb
C. thick ascending limb
D. collecting ducts
41. The tubular fluid at the end of the PT is
with respect to plasma
A. isotonic
B. hypotonic
C. hypertonic
42. Which is the ‘concentrating segment’ of the nephron?
A. Descending limb of loop of Henle
B. Thin ascending limb of loop of Henle
C. Thick ascending limb of loop of Henle
D. Collecting ducts
43. Which portion of the tubule is least permeable to water?
A. Proximal tubule
B. Thin descending limb of Henle’s loop
C. Thick ascending limb of Henle’s loop
D. Cortical collecting duct
44. Which is the fundamental mechanism generating hypertonicity in the medullary interstitium?
A. Active transport of NaCl in thick ascending limb
B. Action of ADH in the collecting ducts
C. Passive recirculation of NaCl in the medullary interstitium
D. Urea permeability of collecting ducts
45. Which of the following transport mechanisms in the macula densa allows it to sense Na and Cl concentrations in the tubular fluid that flows past this segment?
A. Apical chloride channels
B. 1Na-1K-2Cl transporter (NKCC2)
C. Na-Cl cotransporter
D. Na-H exchanger
E. ROMK exchanger
46. What does the macula densa sense?
A. Na concentration of fluid delivered to it
B. Cl concentration of the fluid delivered to it
C. Volume of fluid delivered to it
47. The ‘diluting segment’ of the nephron is:
A. proximal tubule
B. descending limb of loop of Henle
C. thick ascending limb of loop of Henle
D. cortical collecting duct
48. ‘Free water’ is formed mainly in the:
A. descending limb of loop of Henle
B. thin ascending limb of loop of Henle
C. thick ascending limb of loop of Henle
D. collecting duct
49. What fraction of filtered water is reabsorbed in the loop of Henle?
A. 15%
B. 25%
C. 35%
D. 5%
50. What fraction of filtered Na is reabsorbed in the loop of Henle?
A. 15%
B. 25%
C. 35%
D. 5%
51. In the absence of medication or disease processes affecting transport in the nephron, fluid entering the early distal tubule is:
A. always isotonic
B. always hypotonic
C. always hypertonic
D. isotonic or hypotonic
E. hypertonic when urine is concentrated
F. hypotonic when urine is dilute
52. Principal cells (P cells) in the cortical collecting duct of the nephron are mainly involved in:
A. secretion of protons
B. potassium reabsorption
C. reabsorption of sodium and chloride
D. ADH-stimulated water reabsorption
53. The retention of ‘free water’ by ADH in the collecting ducts is mediated mainly by which aquaporin in the luminal membrane?
A. AQP-1
B. AQP-2
C. AQP-3
D. AQP-4
54. Vasa recta receive blood from:
A. afferent arterioles of cortical nephrons
B. afferent arterioles of juxtamedullary nephrons
C. efferent arterioles of cortical nephrons
D. efferent arterioles of juxtamedullary nephrons
55. Hypertonicity in the inner medulla is maintained because:
A. vasa recta receive 50% of renal blood flow
B. of the low blood flow rate through vasa recta
C. NaCl passively moves into the medullary interstitium from the thin ascending limb
56. The system for the formation of concentrated or dilute urine does not include the:
A. proximal convoluted tubule
B. loop of Henle
C. collecting ducts
D. vasa recta
E. medullary interstitium
57. Urea is reabsorbed from:
A. thick ascending limb of loop of Henle
B. distal convoluted tubule
C. cortical collecting ducts
D. inner medullary collecting ducts
58. The reabsorption of urea by the inner medullary collecting ducts is dependent on facilitation by:
A. angiotensin II
B. aldosterone
C. antidiuretic hormone
D. atrial natriuretic peptide
59. Which segment of the nephron is permeable to urea?
A. Descending limb of loop of Henle
B. Thin ascending limb of loop of Henle
C. Thick ascending limb of loop of Henle
60. In the inner medullary interstitium, which of the following contributes the most to osmolality?
A. NaCl
B. Urea
61. ‘Free water’ formation in the lumen of the nephron is essential for production of:
A. dilute urine
B. concentrated urine
62. The principal regulator of plasma osmolality is:
A. plasma [Na]
B. antidiuretic hormone
C. aldosterone
D. angiotensin II
E. renin
63. Plasma potassium concentration is chiefly
regulated by:
A. aldosterone
B. vasopressin (ADH)
C. renin
D. ANP
64. Which ion is both secreted and absorbed by the nephron?
A. Na
B. K
C. Cl
D. Ca
65. Potassium secretion occurs mainly in:
A. PT
B. early distal tubule
C. late distal tubule
D. cortical collecting ducts
E. loop of Henle
66. In a euvolemic normotensive healthy adult with, ADH secretion is most likely to be stimulated by:
A. intake of 500 ml water
B. intake of 30 ml of 10% ethanol
C. 2.5 mg of enalapril
D. ingestion of a 400 g meal consisting exclusively of simple sugars
67. Which of the following inhibits ADH secretion?
A. Hyperosmolality
B. Exercise
C. Angiotensin II
D. Ethanol
68. Which of the following is consistent with hypotonic urine?
A. A high Uosm / Posm ratio
B. A urinary pH of 7
C. Positive free water clearance
D. Urine specific gravity of 1015
69. In humans, when urine is maximally concentrated, the ratio of osmolality of urine to plasma is about:
A. 1.2
B. 2
C. 4.6
D. 7.5
70. The obligatory 24 hr urine volume to maintain solute homeostasis in a healthy adult male weighing 65 kg and consuming a balanced 2000 calorie diet is approximately
A. 100 ml
B. 500 ml
C. 1000 ml
D. 1500 ml
71. Water deprivation fails to produce an increase in urine osmolality in:
A. neurogenic diabetes insipidus
B. nephrogenic diabetes insipidus
72. When the osmolality of urine is 1400 mOsm/Kg H2O, the greatest amount of water is reabsorbed in:
A. cortical collecting ducts
B. outer medullary collecting ducts
C. inner medullary collecting ducts
D. proximal tubule
E. descending thin limbs
73. In a healthy adult, the urge to void urine is first felt at a bladder volume of about:
A. 50 ml
B. 150 ml
C. 250 ml
D. 350 ml
74. In a healthy adult, the volume of urine in the bladder that initiates reflex contraction of the bladder is about:
A. 50–100 ml
B. 100–200 ml
C. 200–300 ml
D. 300–400 ml
75. What is the immediate effect of spinal cord transection on bladder function?
A. Urinary retention
B. Overflow incontinence
C. Anuria
76. Which of the following is characterized by a hypercontractile, shrunken bladder, increased frequency of urination and incontinence?
A. Deafferented bladder
B. Denervated bladder
C. Spastic neurogenic bladder
D. Bladder in acute paraparesis
77. Which of the following is not a feature of tabes dorsalis?
A. Bladder wall hypertrophy
B. Distended bladder
C. Urinary retention
D. Incontinence
78. The most abundant buffer in proximal tubular fluid is:
A. bicarbonate
B. phosphate
C. ammonia
79. Normally, most of the filtered HCO3 is reabsorbed from:
A. PT
B. distal tubule
C. cortical collecting duct
D. loop of Henle
80. In the nephron, the highest amount of H ions is secreted into tubular lumen in the:
A. PCT
B. DCT
C. collecting ducts
D. loop of Henle
81. The principal mechanism of H+ secretion in the proximal convoluted tubule is via:
A. Na–H exchanger
B. H–ATPase
C. H–K ATPase
D. H–Ca exchanger
82. The principal site of ammoniagenesis in the nephron is:
A. PT
B. Loop of Henle
C. Early distal tubule
D. Late distal tubule
E. Outer medullary collecting duct
83. The principle site of acidification of tubular fluid is:
A. proximal convoluted tubule
B. loop of Henle
C. the aldosterone sensitive distal nephron
D. urinary bladder
84. The principal mechanism for acid secretion by type A intercalated cells in the nephron is:
A. H–ATPase
B. Na–H exchanger
C. H–Ca exchanger
D. H–K ATPase
85. Normally, in urine, most of the H+ is tied up with:
A. bicarbonate
B. phosphate
C. ammonia
86. Urinary ratio of NH4+ to titratable acid ranges from:
A. 1-2.5
B. 2-5
C. 0.1-0.5
D. 5-7
87. Normally, most of the titratable acidity of urine is attributable to acid buffered by:
A. bicarbonate
B. phosphate
C. ammonia
D. uric acid
E. creatinine
88. Type B intercalated cells in the collecting duct are concerned with:
A. secretion of protons
B. controlled bicarbonate secretion
C. ADH-stimulated water reabsorption
D. Na reabsorption
89. In arterial blood gas analysis, which of the following is calculated?
A. Arterial pH
B. Plasma bicarbonate
C. PaCO2
D. PaO2
90. In a healthy human with an arterial plasma pH of 7.38, and normal levels of electrolytes, the anion gap reflects the plasma concentration of:
A. HCO3
B. chloride
C. protein anions
91. In a normal adult human on an average diet, and with an arterial plasma pH of 7.37, which of the following is least likely to be present in urine obtained first thing in the morning?
A. Calcium
B. Urea
C. Uric acid
D. HCO3
92. If PaCO2 is 80 mm Hg and arterial plasma [H+] is 80 nmol/L, then plasma [HCO3] is:
A. 40 mmol/L
B. 28 mmol/L
C. 24 mmol/L
D. 10 mmol/L
93. In Question 92, what is the acid-base status?
A. Compensated metabolic alkalosis
B. Uncompensated respiratory acidosis
C. Compensated respiratory acidosis
D. Uncompensated metabolic acidosis
E. Normal acid-base status
94. Sodium bicarbonate should not be administered to a patient with a/an:
A. arterial blood pH of 7.1
B. serum [HCO3] of 12 mM
C. PaO2 of 50 mm Hg
D. PaCO2 of 68 mm Hg
95. The most common acid-base disturbance in patients who are on mechanical ventilators is:
A. metabolic acidosis
B. metabolic alkalosis
C. respiratory acidosis
D. respiratory alkalosis
96. In a patient with acidosis, arterial plasma bicarbonate is 12 mmol/L. If the acidosis were solely due to loss of bicarbonate, PaCO2 is expected to be between
A. 16 and 20 mm Hg
B. 20 and 24 mm Hg
C. 24 and 28 mm Hg
D. 28 and 32 mm Hg
97. The following values were obtained from a patient diagnosed to have metabolic acidosis. PaO2 = 90 mm Hg, PaCO2 = 30 mm Hg, plasma [HCO3] = 10 mM, the pH of CSF in this patient would be about:
A. 7.20
B. 7.25
C. 7.33
D. 7.40
98. Which of the following is not elevated in ethylene glycol poisoning?
A. Anion gap
B. Base excess
C. Osmolar gap
D. Serum osmolality
99. The severity of acidosis is related to:
A. anion gap
B. pH of arterial plasma
C. pH of ICF and plasma
D. plasma HCO3
100. The following data are obtained on a patient on a 2000 kcal diet that includes 1 g of protein per kg body weight.
Creatinine clearance = 100 ml/min Plasma pH = 7.4
Serum Na = 140; K = 5; HCO3 = 24; Cl = 105
mmol/L
Urine NH4 = 20 mmol/L
Urine titratable acidity = 20 mmol/L Urine volume = 2 liters per day
Approximately how much new HCO3 is generated per day?
A. 20 mmol
B. 40 mmol
C. 60 mmol
D. 80 mmol
