RENAL - ACID BASE – ADRENAL PHYSIOLOGY



RENAL - ACID BASE – ADRENAL PHYSIOLOGY

MCQS

22nd Dec 2011

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1. Secretion of K+ by the distal tubule will be decreased by which of the following?

a. Metabolic alkalosis

b. A high K+ diet

c. Hyperaldosteronism

d. Spironolactone administration

2. A woman has a plasma osmolarity of 300 mosm/(. The correct diagnosis is

a. SIADH

b. Water deprivation

c. Central diabetes insipidus

d. Nephrogenic diabetes insipidus

3. The following blood gas picture is most consistent with: pH = 7.56; pCO2 = 20mmHg; pO2 = 100mmHg; bicarb = 25mmol/(

a. Emphysema

b. Prolonged vomiting

c. Bicarbonate ingestion

d. 2 week residence at high altitude

4. The principal buffer in interstitial fluid is which of the following?

a. Carbonic acid

b. Hb

c. Phosphate

d. Compounds containing histidine

5. Regarding absorption of Na+ in the proximal tubule, which of the following is true?

a. The proximal tubule reabsorbs 80% of the filtered sodium load

b. Absorption of Na+ causes increasing hypertonicity in the tubule lumen

c. Absorption is powered by the Na+/H+ ATPase

d. Shares a common carrier with glucose

6. Which of the following agents does not cause contraction of the mesangial cells in the glomerulus?

a. Angiotensin II

b. Noradrenaline

c. Histamine

d. Dopamine

7. The lower pH limit of the urine is which of the following?

a. 1.0

b. 3.5

c. 4.5

d. 6.0

8. ADH (vasopressin) secretion is increased by which of the following?

a. Alcohol

b. Carbamazepine

c. ( extracellular fluid volume

d. Angiotensin I

9. With respect to the counter current system, which is false?

a. Solutes diffuse out of vessels conducting blood toward the cortex

b. Water diffuses out of ascending vessels

c. Water diffuses into the collecting ducts

d. Counter current exchange is passive and can operate even if counter current multiplication ceases

10. Which of the following is most permeable to water?

a. Thin ascending Loop of Henle

b. Distal convoluted tubule

c. Thin descending Loop of Henle

d. Thick ascending limp of Loop of Henle

11. pH 7.16; pCO2 = 24mmHg; pO2 = 100mmHg; bicarbonate = 6mmol/(; K+ = 3.4mmol/(

Which of the following is MOST likely to cause the above picture

a. Cyanide poisoning

b. Hyperventilation

c. Liquorice ingestion

d. Addison’s disease

12. Metabolic alkalosis can be caused by all of the following EXCEPT

a. Hyperaldosteronism

b. Hyperventilation

c. Hypokalaemia

d. Volume depletion

13. The consumption of oxygen by the kidney, which is incorrect?

a. Decreases as blood flow increases

b. Is regulated by erythropoietin

c. Remains constant as blood flow increases

d. Is greatest in the medulla

14. An increase in the concentration of plasma potassium causes an increase in which of the following?

a. Release of renin

b. Secretion of aldosterone

c. Secretion of ADH

d. Release of natriuretic hormone

15. Which of the following would increase GFR?

a. Constriction of the afferent arteriole

b. A decrease in afferent arteriolar pressure

c. Compression of the renal capsule

d. A decrease in the concentration of plasma protein

16. The greatest amount of hydrogen ion secreted by the proximal tubule is associated with which of the following?

a. Excretion of potassium ion

b. Reabsorption of calcium ion

c. Reabsorption of bicarbonate ion

d. Reabsorption of phosphate ion

17. All of the following comparisons between the distal nephron and the proximal tubule are correct EXCEPT

a. The distal nephron is less permeable to hydrogen ion than is the proximal tubule

b. The distal nephron has a more negative intraluminal potential than does the proximal tubule

c. The distal nephron secretes more potassium than does the proximal tubule

d. The distal nephron secretes more hydrogen ion than does the proximal tubule

18. Urinary volume is increased by all of the following EXCEPT

a. Sympathetic stimulation

b. Diabetes insipidus

c. Increased renal arterial pressure

d. Infusion of mannitol

19. Which one of the following statements about aldosterone is correct?

a. It produces its effect by activating cAMP

b. It produces its effects by increasing membrane permeability to potassium

c. It causes an increased reabsorption of hydrogen ion

d. It is secreted in response to an increase in BP

20. The ability of the kidney to excrete a concentrated urine will increase if

a. The permeability of the proximal tubule to water decreases

b. The rate of blood flow through the medulla decreases

c. The rate of flow through the Loop of Henle increases

d. The activity of the Na-K pump in the Loop of Henle decreases

21. Which of the following returns closest to normal during chronic respiratory acidosis?

a. Arterial PCO2

b. Arterial PO2

c. Plasma concentration of bicarbonate

d. Arterial concentration of hydrogen ion

22. Renal correction of hyperkalaemia will result in which of the following?

a. Alkalosis

b. Increased secretion of HCO3-

c. Acidosis

d. Increased excretion of Na+

23. In controlling the synthesis and secretion of aldosterone – which of the following factors is LEAST important?

a. Renin

b. Angiotensin II

c. ACTH

d. Concentration of plasma K+

24. Ammonia is an effective and important urinary buffer for which of the following reasons?

a. Its production in the kidney ( during chronic alkalosis

b. The walls of the renal tubules are impermeable to NH3

c. The walls of the renal tubules are impermeable to NH4+

d. Its acid base reaction has a low pKa

25. pH 7.67, PO2 120mmHg on O2; PCO2 60mmHg and bicarbonate 36mmol/l on a blood gas is indicative of

a. Respiratory alkalosis

b. Mixed metabolic and respiratory alkalosis

c. Respiratory acidosis

d. Metabolic alkalosis

26. The TMg for women (transport maximum for glucose) in the kidney is about

a. 75mg/min

b. 100mg/min

c. 150mg/min

d. 300mg/min

27. A loss of function mutates in the gene of which of the following proteins is associated with nephrogenic diabetes insipidus

a. Aquaporin -1

b. Aquaporin -2

c. Aquaporin -3

d. Aquaporin -4

28. Dehydration increases the plasma concentration of all of the following EXCEPT

a. Vasopressin

b. Angiotensin II

c. Noradrenaline

d. Atrial natriuretic peptide

29. Calculate the anion gap from these results –

Na+ 142; K+ 3.5mmol/l; glucose 6mm0l/l; chloride 110mm0l/l; bicarbonate = 10mmol/l; urea = 7.0mmol/l

a. 15

b. 17

c. 22

d. 29

30. Regarding water excretion, which is true?

a. At least 87% of filtered water in kidney is reabsorbed

b. About 5% of filtered water is removed in the distal tubule

c. Aquaporin -1 plays a major role in water conservation, although it is unaffected by vasopressin

d. All of the above are correct

31. H+ secretion in the distal nephron is enhanced by all of the following EXCEPT

a. An increase in the level of plasma aldosterone

b. An increase in the tubular lumen concentration of poorly reabsorbable ions

c. Hyperkalaemia

d. Respiratory acidosis

32. Renin release from the juxtaglomerular apparatus is inhibited by which of the following?

a. ( agonists

b. Prostaglandins

c. Increased pressure within the afferent arterioles

d. Stimulation of the macula densa

33. Which of the following substances will be more concentrated at the end of the proximal tubule than at the beginning of the proximal tubule?

a. Glucose

b. Creatinine

c. Bicarbonate

d. Phosphate

34. Ammonia is an effective and important urinary buffer for which of the following reasons?

a. Its production in the kidney decreases during chronic acidosis

b. The walls of the renal tubules are impermeable to NH3

c. The walls of the renal tubules are impermeable to NH4+

d. Its acid-base reaction has a low pKa

35. The following blood picture is most likely consistent with:

( Na+ = 120mmol/l, K+ = 6.7 mmol/l, chloride = 95mmol/l, bicarbonate = 20.)

a. Normality

b. 1( adrenal insufficiency

c. 1( hyperaldosteronism

d. Diabetes insipidus

36. What is the glomerular filtration rate when urine flow = 1ml/minute; arterial plasma level of inulin = 0.20mg/ml, and urine concentration of inulin is 40mg/ml?

a. 80ml/min

b. 150ml/min

c. 200ml/min

d. 400ml/min

37. Which of the following substances is both reabsorbed +/- secreted in the kidney?

a. Potassium

b. Sodium

c. Bicarbonate

d. Glucose

38. Regarding renal handling of sodium, which is true?

a. Sodium is reabsorbed in the proximal tubule by the Na+ /2Cl-/ K+ transporter.

b. Mineralocorticoids increase tubular reabsorption of sodium.

c. Sodium excretion is decreased by drugs that decrease renal acid secretion by inhibiting carbonic anhydrase.

d. Overall = 90% of sodium filtered at the glomerulus is reabsorbed.

39. Regarding water excretion from the kidney, which is true?

a. Aquaporin 2 – is found in the cells of the thin ascending loop of Henle.

b. At least 67% of filtered water is absorbed – even when urine volume is very high.

c. The ascedning limb of the loop of Henle is impermeable to water.

d. When vasopressin is absent – the collecting duct epithelium is permeable to water.

40. Which of the following is false with respect to angiotensins?

a. Angiotensin I’s sole action is as a precursor of Angiotensin II

b. Angiotensin II is 4 to 8 times most potent vasoconstrictor than noradrenaline

c. Patients with cirrhosis are less responsive to Angiotensin II

d. Angiotensin III has less aldosterone stimulating effect than Angiotensin II

41. Regarding buffers in body fluids which is false?

a. H2PO4- is a major buffer in the blood

b. bicarbonate is a principal buffer in interstitial fluid

c. proteins are important buffers in intracellular fluid

d. proteins are one of the major buffers in the blood

 

 

42. Regarding pH of body fluid which is true?

a. gastric acid pH is around 3.0

b. pancreatic secretion pH is around 5.0

c. plasma pH is normally around 7.0

d. urine can sometimes be as acidic as a pH of 4.5

 

 

43. Renal acid secretion is altered by a change in which of the following?

a. partial pressure of CO2

b. concentration of serum potassium

c. level of carbonic anhydrase

d. all of the above

 

 

44. Regarding ammonia secretion which is false?

a glutaminase enzyme helps facillitate ammonia secretion

b. glutamic dehydrogenase helps facillitate ammonia secretion

c. the amount of ammonium ion excreted is reduces as urine pH increases

d. non-ionic diffusion is process by which the NH4+ concentration gradient is maintained across the tubules

 

 

45. Which of the following is true of the renal secretion of H+?

a. facilitated by renal tubular bicarbonate, ammonia and H2PO4-

b. occurs via the sodium, hydrogen antiport in the interstial border of  proximal tubule cells

c. all of the above

d. none of the above

 

 

46. What stimulates Vasopressin (ADH) secretion?

a. Increased osmotic pressure of plasma

b. Decreased ECF volume

c. Angiotensin II

d. All of the above

47. What decreases Vasopressin secretion?

a. Alcohol

b. Standing

c. Carbamezepine

d. Nausea & vomiting

48. Renin secretion is increased by which of the following?

a. Vasopressin (ADH)

b. Angiotensin II

c. catecholamines

d. hypertension

49. Which is true in regards to Angiotensin?

a. Its precursor, Angiotensinogen, is produced by the Adrenals.

b. Is inactive in its Angiotensin III form.

c. It stimulates both aldosterone & vasopressin release

d. Is most active as Angiotensin I

50. What is true regarding erythropoietin?

a. 85% comes from the kidneys, the remainder from the liver.

b. Has a half life of 5hrs, but its effect takes 2-3 days to appear.

c. As plasma haematocrit decreases, the erythropoietin level increases in a linear fashion.

d. All of the above

51. Which of the following causes relaxation of mesangial cells in the glomerulus?

a. Endothelins

b. Angiotensin II

c. Noradrenalin

d. Dopamine

52. Regarding substances used for the measurement of GFR which of the following is false?

a. Must be readily secreted and reabsorbed in the tubules

b. Must not be metabolised

c. Must be non-toxic

d. Must be freely filtered in the glomerulus

53. As stimulation of the renal nerves increases which of the following is false?

a. Renin secretion is increases

b. Na+ reabsorption is increases

c. GFR increases

d. Sensitivity of the JG cells increases

54. Where is Na+ reabsorbed in the largest quantities?

a. Proximal tubule

b. Thick ascending loop of Henle

c. Distal convoluted tubule

d. Collecting ducts

55. In which portion of the nephron does Aldosterone regulate sodium absorption?

a. Proximal tubule

b. Thick ascending loop of Henle

c. Distal convoluted tubule

d. Collecting ducts

56. Which is true regarding the nephron?

a. the glomerular basement membrane allows free passage of all substances

less than 4mm

b. the nephron is 200um in diameter

c. podocytes form filtration slits 25nm wide

d. glomerular capillary endothelium has pores 200nm in diameter

57. With respect to cellular function in the kidney, which is false?

a. juxtaglomerular cells secrete rennin

b. I cells secrete prostagladins

c. mesangial cells take up immune complexes

d. P cells are involved in ADH-stimulated water reabsorption

58. Which is true regarding renal blood flow?

a. a high protein diet increases renal blood flow

b. Angiotensin II and dopamine increases renal blood flow

c. protagladins decrease cortical blood flow

d. noradrenaline constricts efferent arterioles

59. Which is false with respect to renal blood flow?

a. the medulla is vulnerable to hypoxia

b. medullary flow is greater than cortical flow

c. cortical PO2 = 50 mmHg

d. clearance of PAH = 630 ml/min

60. Which of the following relaxes mesangial cells?

a. Angiotensin II

b. PGF2

c. PGE2

d. Histamine

61. Which of the following is not secreted by the tubules?

a. creatinine

b. uric acid

c. potassium

d. sodium

62. What is the renal threshold for glucose in men?

a. 375 mg/min

b. 300 mg/dL

c. 180 mg/dL

d. 300 mg/min

63. Regarding permeability and transport in the nephron, which is false?

a. the thin portion of the loop of Henle is impermeable to Na+

b. the thick ascending limb is impermeable to water

c. the tubular fluid is isotonic to plasma at the end of the loop of Henle

d. most water and Na+ reabsorption occurs in the proximal convoluted tubule

64. Which of the following does not increase Na+ excretion?

a. ANP

b. Angiotensin II

c. increased GFR

d. PGE2

65. Which is true regarding K+ excretion?

a. rate of excretion is proportionate to rate of flow of tubular fluid

b. Most K+ excretion occurs in the proximal tubules

c. it is decreased when Na+ concentration is high in the distal tubule

d. it is decreased when H+ secretion is decreased

66. Which is incorrect regarding mechanism of action of some diuretics?

a. Spironolactone – inhibits action of aldosterone in collecting ducts

b. amiloride – inhibits ENaCs in collecting ducts

c. frusemide – inhibits Na-K-2Cl channels in the thick ascending Loop of Henle

d. Thiazides – inhibits Na-H exchange in proximal convoluted tubule

67. Regarding body fluid composition, which is true?

a. Phosphates are more abundant in plasma than in intracellular fluid

b. Cl- is the dominant anion in intracellular fluid

c. Proteins tend to have a negative charge at physiologic pH

d. Extracellular fluid constitutes 40% if the total body weight

68. Which of the following is true with respect to buffers and fluid/solute movement?

a. The buffering capacity of an acid is best when its pKa is higher than the pH of the solution

b. Fick’s law states diffusion is inversely proportionate to the cross-sectional area

c. Osmolarity if affected by the volume of the various solutes in the solution

d. Because of glucose metabolism, infusion of 5% glucose has the net effect of infusing a hypertonic solution

69. During replication, which is incorrect?

a. During mitosis, separation of the DNA is catalysed by DNA polymerase

b. In RNA, uracil replaces the thymine in DNA

c. Transcription is the production of RNA from DNA

d. Translation is catalysed by RNA polymerase

70. Which of the following is a nutritionally essential amino acid?

a. Arginine

b. Alanine

c. Glutamine

d. Tyrosine

71. Which is incorrect regarding plasma lipids?

a. Free fatty acids can circulate as lipoproteins bound to albumin

b. The endogenous pathway transports lipoproteins from the intestine to the liver

c. Exogenous ingested lipids are transported by chylomicrons

d. Lipoprotein lipase requires heparin as a cofactor

72. Regarding buffering systems which is correct?

a. Carbonic anhydrase is found in high concentrations in the gastric-acid secreting cells and the renal tubular cells

b. Haemoglobin acts as a buffer

c. In a respiratory acidosis and alkalosis, buffering is almost all intracellular

d. All of the above are correct

73. Regarding the Siggaard-Andersen curve nomogram, which is correct?

a. The nomogram plots total CO2 concentration against pH

b. Higher Hb concentrations cause a loss of buffering ability

c. The buffer base is equal to the total number of buffer anions

d. The Base Excess is positive in acidosis

74. Renal acid secretion is enhanced by which of the following factors?

a. High PCO2, Low K+, Aldosterone activity

b. High PCO2, High K+, Aldosterone activity

c. Low PCO2, Low K+, Aldosterone inhibition

d. High PCO2, Low K+, Aldosterone inhibition

75. Regarding compensatory mechanisms for acid-base disturbance, which is incorrect?

a. HCO3- is reabsorbed in exchange for H+

b. Cations are lost producing diuresis with low acid loads

c. The limiting urinary pH is about 4.5

d. Respiratory compensation of a metabolic alkalosis is limited by the mechanisms of the carotid and aortic chemoreceptors

76. With regard to ammonia secretion, which is false?

a. Ammonia is very water soluble so diffuses into urine along its concentration gradient

b. In chronic acidosis, the amount of excreted ammonia decreases

c. The process of ammonia secretion into the urine is called ionic diffusion

d. All of the above

77. Which of the following is correct regarding Na+ handling in the kidney:

a. 60% is reuptaken in the Collecting ducts

b. The Na-K-2Cl cotransporter is present in the thick ascending loop

c. Aldosterone mainly affects Na+ transport in the PCT

d. The majority of filtered Na+ is not reabsorbed

78. When measuring GFR using Inulin, if Urine flow is 1ml/min, Plasma inulin concentration is 0.25mg/ml and Urine inulin concentration is 30mg/ml, the GFR is:

a. 120ml/min

b. 12ml/min

c. 7.5ml/min

d. 30ml/min

79. Which of the following factors and its effect on renal blood flow is correctly paired?

a. Noradrenaline: Increases RBF

b. Acetylcholine: Decreases RBF

c. Angiotensin II: Decreases RBF

d. Dopamine: Decreases RBF

80. Regarding Glucose handling in the kidney, which is true?

a. 50% of filtered glucose is reabsorbed

b. Glucose is transported together with Na+

c. There is no threshold for the amount of Glucose that can be absorbed per unit volume

d. The main transport of Glucose occurs in the DCT

81. The effect of salt and water concentration in the Thick ascending Loop on the Renal arteriolar pressure is called:

a. Autoregulation

b. Glomerulotubular balance

c. Splay

d. Tubuloglomerular feedback

82. Principle buffers in the blood include all EXCEPT:

a. Sodium

b. Bicarbonate

c. Protein

d. Haemoglobin

83. Match pH with it’s correct fluid:

a. Gastric HCl – pH 5.0

b. Pancreatic juice – pH 8.0

c. Maximal urine acidity – pH 4.0

d. Normal plasma – pH 7.2

84. Which of the following is true with regards to urinary pH changes:

a. pH of urine varies from 4.0 to 9.0

b. For each H+ ion excreted there is a net gain of 2 HCO3- ions

c. Has implications for the body’s electrolyte and acid-base economy.

d. When base is added to the body fluids, the HCO3- ions are buffered raising the plasma OH-.

85. In respiratory acidosis:

a. There is a reduction in arterial PCO2 caused by increased ventilation.

b. the interior of cells become less acidic with increased PCO2

c. Renal tubular H+ secretion is decreased.

d. HCO3- reabsorption is increased.

86. In metabolic acidosis:

a. The plasma pH is high

b. The plasma HCO3- is low

c. The arterial pCO2 remains high

d. The plasma pH, HCO3- and pCO2 are all high

87. Regarding vasopressin, which is false?

a. All vasopressin receptors are G-coupled

b. It increases expression of aquaporin-1 channels in the collecting ducts

c. Haemorrhage is a potent stimulus for secretion

d. V1a receptors are also found in the liver and brain

88. Which of the following increases vasopressin secretion?

a. Decreased osmotic pressure of plasma

b. Increased ECF volume

c. Nausea and vomiting

d. Alcohol

89. Which of the following does not increase renin secretion?

a. Cirrhosis

b. Cardiac failure

c. Diuretics

d. Lying down

90. In the kidney, erythropoietin is secreted by:

a. Cells in the peritubular capillary bed

b. Cells in the distal tubules

c. Cells in the proximal tubules

d. Cells in the macula densa

91. Dehydration increases plasma concentration of all of the following except?

a. Aldosterone

b. Angiotensin II

c. Vasopressin

d. ANP

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