chapter 5 BRS physiology

12. A buffer pair (HA/A-) has a pK of 5.4. At a blood pH of 7.4, the concentration of HA is (A) 1/l00 that of A- (B) 1/10 that of A- (C) equal to that of A- (D) 10 times that of A- (E) 100 times that of A-

A

13. Which of the following would produce an increase in the reabsorption of isosmotic fluid in the proximal tubule? (A) Increased filtration fraction (B) Extracellular fluid (ECF) volume expansion (C) Decreased peritubular capillary protein concentration (D) Increased peritubular capillary hydrostatic pressure (E) Oxygen deprivation

A

26. Which of the following causes hyperkalemia? (A) Exercise (B) Alkalosis (C) Insulin injection (D) Decreased serum osmolarity (E) Treatment with β-agonists

A

28. Which of the following is an action of parathyroid hormone (PTH) on the renal tubule? (A) Stimulation of adenylate cyclase (B) Inhibition of distal tubule K+ secretion (C) Inhibition of distal tubule Ca2+ reabsorption (D) Stimulation of proximal tubule phosphate reabsorption (E) Inhibition of production of 1,25-dihydroxycholecalciferol

A

34. Which set of arterial blood values describes a patient with a 5-day history of vomiting? pH HCO3 - (mEq/L) Pco2 (mm Hg) (A) 7.65 48 45 (B) 7.50 15 20 (C) 7.40 24 40 (D) 7.32 30 60 (E) 7.31 16 33

A

38. At which nephron site is the tubular fluid inulin concentration lowest? (A) Site A (B) Site B (C) Site C (D) Site D (E) Site E

A

39. At which nephron site is the tubular fluid glucose concentration highest? (A) Site A (B) Site B (C) Site C (D) Site D (E) Site E

A

41. Which curve describes the alanine profile along the nephron? (A) Curve A (B) Curve B (C) Curve C (D) Curve D

A

A 45-year-old woman develops severe diarrhea while on vacation. She has the following arterial blood values: pH = 7.25 Pco2 = 24 mm Hg [HCO3 -] = 10 mEq/L Venous blood samples show decreased blood [K+] and a normal anion gap. 3. The correct diagnosis for this patient is (A) metabolic acidosis (B) metabolic alkalosis (C) respiratory acidosis (D) respiratory alkalosis (E) normal acid-base status

A

18. A patient has the following arterial blood values: pH = 7.52 Pco2 = 20 mm Hg [HCO3 −] = 16 mEq/L Which of the following statements about this patient is most likely to be correct? (A) He is hypoventilating (B) He has decreased ionized [Ca2+] in blood (C) He has almost complete respiratory compensation (D) He has an acid-base disorder caused by overproduction of fixed acid (E) Appropriate renal compensation would cause his arterial [HCO3 -] to increase

B

20. Which of the following causes a decrease in renal Ca2+ clearance? (A) Hypoparathyroidism (B) Treatment with chlorothiazide (C) Treatment with furosemide (D) Extracellular fluid (ECF) volume expansion (E) Hypermagnesemia

B

22. A woman has a plasma osmolarity of 300 mOsm/L and a urine osmolarity of 1200 mOsm/L. The correct diagnosis is (A) syndrome of inappropriate antidiuretic hormone (SIADH) (B) water deprivation (C) central diabetes insipidus (D) nephrogenic diabetes insipidus (E) drinking large volumes of distilled water

B

31. Which set of arterial blood values describes a patient with partially compensated respiratory alkalosis after 1 month on a mechanical ventilator? A) 7.65 48 45 (B) 7.50 15 20 (C) 7.40 24 40 (D) 7.32 30 60 (E) 7.31 16 33

B

43. A 5-year-old boy swallows a bottle of aspirin (salicylic acid) and is treated in the emergency room. The treatment produces a change in urine pH that increases the excretion of salicylic acid. What was the change in urine pH, and what is the mechanism of increased salicylic acid excretion? (A) Acidification, which converts salicylic acid to its HA form (B) Alkalinization, which converts salicylic acid to its A- form (C) Acidification, which converts salicylic acid to its A- form (D) Alkalinization, which converts salicylic acid to its HA form

B

7. The following information was obtained in a 20-year-old college student who was participating in a research study in the Clinical Research Unit: Plasma Urine [Inulin] = 1 mg/mL [Inulin] = 150 mg/mL [X] = 2 mg/mL [X] = 100 mg/mL Urine flow rate = 1 mL/min Assuming that X is freely filtered, which of the following statements is most correct? (A) There is net secretion of X (B) There is net reabsorption of X (C) There is both reabsorption and secretion of X (D) The clearance of X could be used to measure the glomerular filtration rate (GFR) (E) The clearance of X is greater than the clearance of inulin

B

17. Which of the following would cause an increase in both glomerular filtration rate (GFR) and renal plasma flow (RPF)? (A) Hyperproteinemia (B) A ureteral stone (C) Dilation of the afferent arteriole (D) Dilation of the efferent arteriole (E) Constriction of the efferent arteriole

C

19. Which of the following would best distinguish an otherwise healthy person with severe water deprivation from a person with the syndrome of inappropriate antidiuretic hormone (SIADH)? (A) Free-water clearance CH O 2 ( ) (B) Urine osmolarity (C) Plasma osmolarity (D) Circulating levels of antidiuretic hormone (ADH) (E) Corticopapillary osmotic gradient

C

23. A patient is infused with paraaminohippuric acid (PAH) to measure renal blood flow (RBF). She has a urine flow rate of 1 mL/min, a plasma [PAH] of 1 mg/mL, a urine [PAH] of 600 mg/mL, and a hematocrit of 45%. What is her "effective" RBF? (A) 600 mL/min (B) 660 mL/min (C) 1,091 mL/min (D) 1,333 mL/min

C

29. A man presents with hypertension and hypokalemia. Measurement of his arterial blood gases reveals a pH of 7.5 and a calculated HCO3− of 32 mEq/L. His serum cortisol and urinary vanillylmandelic acid (VMA) are normal, his serum aldosterone is increased, and his plasma renin activity is decreased. Which of the following is the most likely cause of his hypertension? (A) Cushing syndrome (B) Cushing disease (C) Conn syndrome (D) Renal artery stenosis (E) Pheochromocytoma

C

9. One gram of mannitol was injected into a woman. After equilibration, a plasma sample had a mannitol concentration of 0.08 g/L. During the equilibration period, 20% of the injected mannitol was excreted in the urine. The woman's (A) extracellular fluid (ECF) volume is 1 L (B) intracellular fluid (ICF) volume is 1 L (C) ECF volume is 10 L (D) ICF volume is 10 L (E) interstitial volume is 12.5 L

C

6. The reabsorption of filtered HCO3 - (A) results in reabsorption of less than 50% of the filtered load when the plasma concentration of HCO3 - is 24 mEq/L (B) acidifies tubular fluid to a pH of 4.4 (C) is directly linked to excretion of H+ as NH4 + (D) is inhibited by decreases in arterial Pco2 (E) can proceed normally in the presence of a renal carbonic anhydrase inhibitor

D

A 45-year-old woman develops severe diarrhea while on vacation. She has the following arterial blood values: pH = 7.25 Pco2 = 24 mm Hg [HCO3 -] = 10 mEq/L Venous blood samples show decreased blood [K+] and a normal anion gap. 4. Which of the following statements about this patient is correct? (A) She is hypoventilating (B) The decreased arterial [HCO3 -] is a result of buffering of excess H+ by HCO3 - (C) The decreased blood [K+] is a result of exchange of intracellular H+ for extracellular K+ (D) The decreased blood [K+] is a result of increased circulating levels of aldosterone (E) The decreased blood [K+] is a result of decreased circulating levels of antidiuretic hormone (ADH)

D

14. Which of the following substances or combinations of substances could be used to measure interstitial fluid volume? (A) Mannitol (B) D2O alone (C) Evans blue (D) Inulin and D2O (E) Inulin and radioactive albumin

E

16. Compared with a person who ingests 2 L of distilled water, a person with water deprivation will have a (A) higher free-water clearance CH O 2 ( ) (B) lower plasma osmolarity (C) lower circulating level of antidiuretic hormone (ADH) (D) higher tubular fluid/plasma (TF/P) osmolarity in the proximal tubule (E) higher rate of H2O reabsorption in the collecting ducts

E

27. Which of the following is a cause of metabolic alkalosis? (A) Diarrhea (B) Chronic renal failure (C) Ethylene glycol ingestion (D) Treatment with acetazolamide (E) Hyperaldosteronism (F) Salicylate poisoning

E

33. Which set of arterial blood values describes a patient with untreated diabetes mellitus and increased urinary excretion of NH4 +? pH HCO3 - (mEq/L) Pco2 (mm Hg) (A) 7.65 48 45 (B) 7.50 15 20 (C) 7.40 24 40 (D) 7.32 30 60 (E) 7.31 16 33

E

37. At which nephron site is the tubular fluid inulin concentration highest during antidiuresis? (A) Site A (B) Site B (C) Site C (D) Site D (E) Site E

E

Which set of arterial blood values describes a patient with chronic renal failure (eating a normal protein diet) and decreased urinary excretion of NH4 +? pH HCO3 - (mEq/L) Pco2 (mm Hg) (A) 7.65 48 45 (B) 7.50 15 20 (C) 7.40 24 40 (D) 7.32 30 60 (E) 7.31 16 33

E

a early PCT b late c tip of loop d DCT e CD 35. At which nephron site does the amount of K+ in tubular fluid exceed the amount of filtered K+ in a person on a high-K+ diet? (A) Site A (B) Site B (C) Site C (D) Site D (E) Site E

E

1. Secretion of K+ by the distal tubule will be decreased by (A) metabolic alkalosis (B) a high-K+ diet (C) hyperaldosteronism (D) spironolactone administration (E) thiazide diuretic administration

D

11. A negative free-water clearance (−C ) H O 2 will occur in a person who (A) drinks 2 L of distilled water in 30 minutes (B) begins excreting large volumes of urine with an osmolarity of 100 mOsm/L after a severe head injury (C) is receiving lithium treatment for depression and has polyuria that is unresponsive to the administration of antidiuretic hormone (ADH) (D) has an oat cell carcinoma of the lung, and excretes urine with an osmolarity of 1,000 mOsm/L

D

15. At plasma para-aminohippuric acid (PAH) concentrations below the transport maximum (Tm), PAH (A) reabsorption is not saturated (B) clearance equals inulin clearance (C) secretion rate equals PAH excretion rate (D) concentration in the renal vein is close to zero (E) concentration in the renal vein equals PAH concentration in the renal artery

D

2. Jared and Adam both weigh 70 kg. Jared drinks 2 L of distilled water, and Adam drinks 2 L of isotonic NaCl. As a result of these ingestions, Adam will have a (A) greater change in intracellular fluid (ICF) volume (B) higher positive free-water clearance CH O 2 ( ) (C) greater change in plasma osmolarity (D) higher urine osmolarity (E) higher urine flow rate

D

21. A patient arrives at the emergency room with low arterial pressure, reduced tissue turgor, and the following arterial blood values: pH = 7.69 [HCO3 -] = 57 mEq/L Pco2 = 48 mm Hg Which of the following responses would also be expected to occur in this patient? (A) Hyperventilation (B) Decreased K+ secretion by the distal tubules (C) Increased ratio of H2PO4 - to HPO4 -2 in urine (D) Exchange of intracellular H+ for extracellular K

D

25. A woman runs a marathon in 90°F weather and replaces all volume lost in sweat by drinking distilled water. After the marathon, she will have (A) decreased total body water (TBW) (B) decreased hematocrit (C) decreased intracellular fluid (ICF) volume (D) decreased plasma osmolarity (E) increased intracellular osmolarity

D

30. Which set of arterial blood values describes a heavy smoker with a history of emphysema and chronic bronchitis who is becoming increasingly somnolent? pH HCO3 35-39. - (mEq/L) Pco2 (mm Hg) (A) 7.65 48 45 (B) 7.50 15 20 (C) 7.40 24 40 (D) 7.32 30 60 (E) 7.31 16 33

D

42. Which curve describes the paraaminohippuric acid (PAH) profile along the nephron? (A) Curve A (B) Curve B (C) Curve C (D) Curve D

D