The diagrams represent various states of abnormal hydration. In each diagram, the normal state (orange and lavender) is superimposed on the abnormal state (dashed lines) to illustrate the shifts in the volume (width of rectangles) and total osmolarity (height of rectangles) of the extracellular and intracellular fluid compartments.
7. Which of the diagrams represents the changes (after osmotic equilibrium) in extracellular and intracellular fluid volumes and osmolarities after the infusion of 1% dextrose?
8. Which of the diagrams represents the changes (after osmotic equilibrium) in extracellular and intracellular fluid volumes and osmolarities after the infusion of 3% sodium chloride?
9. Which of the diagrams represents the changes (after osmotic equilibrium) in extracellular and intracellular fluid volumes and osmolarities in a patient with the syndrome of inappropriate antidiuretic hormone (excessive secretion of antidiuretic hormone)?
10. After receiving a renal transplant, a patient develops severe hypertension (170/110 mm Hg). A renal arteriogram indicates severe renal artery stenosis in his single remaining kidney, with a reduction in GFR to 25% of normal. Which of the following changes, compared with normal, would be expected in this patient, assuming steady-state conditions?
12. If a patient has a creatinine clearance of 90 ml/min, a urine flow rate of 1 ml/min, a plasma K+ concentration of 4 mEq/L, and a urine K+ concentration of 60 mEq/L, what is the approximate rate of K+ excretion?
13. Which of the following changes would be expected in a patient with diabetes insipidus due to a lack of antidiuretic hormone (ADH) secretion?
14. A patient with severe hypertension (blood pressure 185/110 mm Hg) is referred to you. A renal magnetic resonance imaging scan shows a tumor in the kidney, and laboratory findings include a very high plasma renin activity of 12 ng angiotensin 1/ml/hr (normal = 1). The diagnosis is a renin-secreting tumor. Which of the following changes would you expect to find in this patient, under steady-state conditions, compared with normal?
15. Which of the following changes, compared with normal, would you expect to find 3 weeks after a patient ingested a toxin that caused sustained impairment of proximal tubular sodium chloride (NaCl) reabsorption? Assume that there has been no change in diet or ingestion of electrolytes.
16. A 26-year-old woman recently decided to adopt a healthier diet and eat more fruits and vegetables. As a result, her potassium intake increased from 80 to 160 mmol/day. Which of the following conditions would you expect to find 2 weeks after she increased her potassium intake, compared with before the increase?
17. An 8-year-old boy is brought to your office with extreme swelling of the abdomen. His parents indicate that he had a very sore throat a “month or so” ago and that he has been “swelling up” since that time. He appears to be edematous, and when you check his urine, you find large amounts of protein being excreted. Your diagnosis is nephrotic syndrome subsequent to glomerulonephritis. Which of the following changes would you expect to find, compared with normal?
18. Which of the following changes would you expect to find after administering a vasodilator drug that caused a 50% decrease in afferent arteriolar resistance and no change in arterial pressure?
A) Decreased renal blood flow, decreased GFR, and decreased peritubular capillary hydrostatic pressure
B) Decreased renal blood flow, decreased GFR, and increased peritubular capillary hydrostatic pressure
C) Increased renal blood flow, increased GFR, and increased peritubular capillary hydrostatic pressure
D) Increased renal blood flow, increased GFR, and no change in peritubular capillary hydrostatic pressure
19. A 32-year-old man complains of frequent urination. He is overweight (280 lb, 5 ft 10 in tall), and after measuring the 24-hr creatinine clearance, you estimate his GFR to be 150 ml/min. His plasma glucose is 300 mg/dL. Assuming that his renal transport maximum for glucose is normal, as shown in the figure above, what would be this patient’s approximate rate of urinary glucose excretion?
20. The clinical laboratory returned the following values for arterial blood taken from a patient: plasma pH = 7.28, plasma HCO3− = 32 mEq/L, and plasma Pco2 = 70 mm Hg. What is this patient’s acid–base disorder?
22. Which of the following would cause the greatest degree of hyperkalemia?
A) Increase in potassium intake from 60 to 180 mmol/day in a person with normal kidneys and a normal aldosterone system
24. Under conditions of normal renal function, which of the following is true of the concentration of urea in tubular fluid at the end of the proximal tubule?
25. Which of the following changes would be expected in a patient with Liddle’s syndrome (excessive activity of amiloride-sensitive sodium channel in the collecting tubule) under steady-state conditions, assuming that intake of electrolytes remained constant?
26. A patient’s urine is collected for 2 hr, and the total volume is 600 ml during this time. Her urine osmolarity is 150 mOsm/L, and her plasma osmolarity is 300 mOsm/L. What is her “free water clearance”?
27. A patient is referred for treatment of hypertension. After testing, you discover that he has a very high level of plasma aldosterone, and your diagnosis is Conn’s syndrome. Assuming no change in electrolyte intake, which of the following changes would you expect to find, compared with normal?
28. A patient with renal disease had a plasma creatinine of 2 mg/dL during an examination 6 months ago. You note that his blood pressure has increased about 30 mm Hg since his previous visit, and the lab tests indicate that his plasma creatinine is now 4 mg/dL. Which of the following changes, compared with his previous visit, would you expect to find, assuming steady-state conditions and no changes in electrolyte intake or metabolism?
30. The maximum clearance rate possible for a substance that is totally cleared from the plasma is equal to which of the following?
31. A patient has the following laboratory values: arterial pH = 7.13, plasma HCO3− = 15 mEq/L, plasma chloride concentration = 118 mEq/L, arterial Pco2 = 28 mm Hg, and plasma Na+ concentration = 141 mEq/L. What is the most likely cause of his acidosis?
32. A 26-year-old man develops glomerulonephritis, and his GFR decreases by 50% and remains at that level. For which of the following substances would you expect to find the greatest increase in plasma concentration?
33. A patient with a history of frequent and severe migraine headaches arrives at your office complaining of stomach pain and breathing rapidly. She informs you that she has had a severe migraine for the past 2 days and has taken eight times the recommended dose of aspirin to relieve her headache during that time. Which of the following changes would you expect to find, compared with normal?
Assume the following initial conditions: intracellular fluid volume = 40% of body weight before fluid administration, extracellular fluid volume = 20% of body weight before fluid administration, molecular weight of NaCl = 58.5g/mol, and no excretion of water or electrolytes.
34. A male patient appears to be dehydrated, and after obtaining a plasma sample, you find that he has hyponatremia, with a plasma sodium concentration of 130 mmol/L and a plasma osmolarity of 260 mOsm/L. You decide to administer 2 L of 3% sodium chloride (NaCl). His body weight was 60 kilograms before giving the fluid. What is his approximate plasma osmolarity after administration of the NaCl solution and after osmotic equilibrium? Assume the initial conditions described above.
35. What is the approximate extracellular fluid volume in this patient after administration of the NaCl solution and after osmotic equilibrium?
37. If the average hydrostatic pressure in the glomerular capillaries is 50 mm Hg, the hydrostatic pressure in the Bowman’s space is 12 mm Hg, the average colloid osmotic pressure in the glomerular capillaries is 30 mm Hg, and there is no protein in the glomerular ultrafiltrate, what is the net pressure driving glomerular filtration?
38. In a patient who has chronic, uncontrolled diabetes mellitus, which of the following sets of conditions would you expect to find, compared with normal?
39. Intravenous infusion of 1 L of 0.45% sodium chloride (NaCl) solution (molecular weight of NaCl = 58.5) would cause which of the following changes, after osmotic equilibrium?
40. The figure above shows the concentration of inulin at different points along the renal tubule, expressed as the tubular fluid/plasma ratio of inulin concentration. If inulin is not reabsorbed, what is the approximate percentage of the filtered water that has been reabsorbed prior to the distal convoluted tubule?
42. Which of the following changes would you expect to find in a patient with primary aldosteronism (Conn’s syndrome) under steady-state conditions, assuming that electrolyte intake remained constant?
43. A diabetic patient has developed chronic renal disease and is referred to your nephrology clinic. According to his family physician, his creatinine clearance has decreased from 100 ml/min to 40 ml/min over the past 4 years. His glucose has not been well controlled, and his plasma pH is 7.14. Which of the following changes, compared with before the development of renal disease, would you expect to find, assuming steady-state conditions and no change in electrolyte intake?
44. A 20-year-old woman arrives at your office complaining of rapid weight gain and marked fluid retention. Her blood pressure is 105/65 mm Hg, her plasma protein concentration is 3.6g/dL (normal = 7.0), and she has no detectable protein in her urine. Which of the following changes would you expect to find, compared with normal?
45. A 48-year-old woman complains of severe polyuria (producing about 0.5 L of urine each hour) and polydipsia (drinking two to three glasses of water every hour). Her urine contains no glucose, and she is placed on overnight water restriction for further evaluation. The next morning, she is weak and confused, her sodium concentration is 160 mEq/L, and her urine osmolarity is 80 mOsm/L. Which of the following is the most likely diagnosis?
46. Furosemide (Lasix) is a diuretic that also produces natriuresis. Which of the following is an undesirable side effect of furosemide due to its site of action on the renal tubule?
47. A patient complains of headaches, and an examination reveals that her blood pressure is 175/112 mm Hg. Laboratory tests give the following results: plasma renin activity = 11.5 ng angiotensin I/ml/hr (normal = 1), plasma Na+ = 144 mmol/L, and plasma K+ = 3.4 mmol/L. A magnetic resonance imaging procedure suggests that she has a renin-secreting tumor. Which of the following changes would you expect, compared with normal?
48. When the dietary intake of K+ increases, body K+ balance is maintained by an increase in K+ excretion primarily by which of the following?
49. A female patient has unexplained severe hypernatremia (plasma Na+ = 167 mmol/L) and complains of frequent urination and large urine volumes. A urine specimen reveals that the Na+ concentration is 15 mmol/L (very low) and the osmolarity is 155 mOsm/L (very low). Laboratory tests reveal: plasma renin activity = 3 ng angiotensin I/ml/hr (normal = 1.0), plasma antidiuretic hormone (ADH) = 30 pg/ml (normal = 3 pg/ml), and plasma aldosterone = 20 ng/dL (normal = 6 ng/dL). Which of the following is the most likely reason for her hypernatremia?
50. Juvenile (type I) diabetes mellitus is often diagnosed because of polyuria (high urine flow) and polydipsia (frequent drinking) that occur because of which of the following?
A) Increased delivery of glucose to the collecting duct interferes with the action of antidiuretic hormone
B) Increased glomerular filtration of glucose increases Na+ reabsorption via the sodium-glucose co-transporter
C) When the filtered load of glucose exceeds the renal threshold, a rising glucose concentration in the proximal tubule decreases the osmotic driving force for water reabsorption
51. You begin treating a hypertensive patient with a powerful loop diuretic (e.g., furosemide). Which of the following changes would you expect to find, compared with pretreatment values, when he returns for a follow-up examination 2 weeks later?
52. In acidosis, most of the hydrogen ions secreted by the proximal tubule are associated with which of the following processes?
53. Administration of a thiazide diuretic (e.g., chlorothiazide) would be expected to cause which of the following effects as its primary mechanism of action?
54. Two weeks after constricting the renal artery of a sole remaining kidney to initially reduce renal artery pressure by 20 mm Hg (from 100 to 80 mm Hg), which of the following changes would you expect, compared with before constriction of the artery?
55. Because the usual rate of phosphate filtration exceeds the transport maximum for phosphate reabsorption, which of the following is true?
56. Which of the following changes, compared with normal, would be expected to occur, under steady-state conditions, in a patient whose severe renal disease has reduced the number of functional nephrons to 25% of normal?
57. In a patient with severe syndrome of inappropriate antidiuretic hormone (excessive antidiuretic hormone secretion), which of the following changes, compared with normal, would you expect to find? Assume steady-state conditions and that the intake of water and electrolytes has remained constant.
Choose the appropriate nephron site in the diagram above.
59. In a patient with severe central diabetes insipidus caused by a lack of antidiuretic hormone secretion, which part of the tubule would have the lowest tubular fluid osmolarity?
60. In a person on a very low potassium diet, which part of the nephron would be expected to reabsorb the most potassium?
62. In a normally functioning kidney, which part of the tubule has the lowest permeability to water during antidiuresis?
64. Which of the following changes would you expect to find in a dehydrated person deprived of water for 24 hours?
65. Which of the following changes would you expect to find after acute administration of a vasodilator drug that caused a 50% decrease in renal efferent arteriolar resistance and no change in afferent arteriolar resistance or arterial pressure?
66. Which of the following would be expected to cause a decrease in extracellular fluid potassium concentration (hypokalemia) at least in part by stimulating potassium uptake into the cells?
67. Which of the following is true of the tubular fluid that passes through the lumen of the early distal tubule in the region of the macula densa?
68. If a person has a kidney transport maximum for glucose of 350 mg/min, a GFR of 100 ml/min, a plasma glucose of 150 mg/dL, a urine flow rate of 2 ml/min, and no detectable glucose in the urine, what would be the approximate rate of glucose reabsorption, assuming normal kidneys?
69. A patient complains that he is always thirsty, and his breath has an acetone smell. You suspect that he has diabetes mellitus, and that diagnosis is confirmed by a urine sample that tests very positive for glucose and a blood sample that shows a fasting blood glucose concentration of 400 mg/dL. Compared with normal, you would expect to find which of the following changes in his urine?
70. Which of the following statements is correct?
A) Urea reabsorption in the medullary collecting tubule is less than in the distal convoluted tubule during antidiuresis
B) Urea concentration in the interstitial fluid of the renal cortex is greater than in the interstitial fluid of the renal medulla during antidiuresis
C) The thick ascending limb of the loop of Henle reabsorbs more urea than the inner medullary collecting tubule during antidiuresis
A person with normal body fluid volumes weighs 60 kg and has an extracellular fluid volume of approximately 12.8 L, a blood volume of 4.3 L, and a hematocrit of 0.4; 57% of his body weight is water. Answer the following three questions based on this information.
75. Which of the following nephron segments is the primary site of magnesium reabsorption under normal conditions?
To evaluate kidney function in a 45-year-old woman with type II diabetes, you ask her to collect her urine over 24 hours. She collects 3600 ml of urine in that period. The clinical laboratory returns the following results after analyzing the patient’s urine and plasma samples: plasma creatinine = 4 mg/dL, urine creatinine = 32 mg/dL, plasma potassium = 5 mmol/L, and urine potassium = 10 mmol/L.
77. What is this patient’s approximate GFR, assuming that she collected all her urine in the 24-hour period?
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