Block 6 Renal Physiology Part 1
Questions and Answers
- 1.
A patient with congestive heart failure has a higher than normal plasma creatinine concentration because of:
- A.
A. A reduced GFR
- B.
B. Increased creatinine secretion
- C.
C. A reduction in protein metabolism
- D.
D. An increase in blood volume
- E.
E. Increased cardiac output
Correct Answer
A. A. A reduced GFRExplanation
In congestive heart failure, the heart is unable to pump blood effectively, leading to decreased blood flow to the kidneys. This reduction in blood flow causes a decrease in the glomerular filtration rate (GFR), which is the rate at which the kidneys filter waste products from the blood. As a result, the plasma creatinine concentration increases because the kidneys are not able to effectively remove creatinine from the blood. This is why option a, a reduced GFR, is the correct answer.Rate this question:
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- 2.
Which of the following would NOT be observed in uncontrolled diabetes mellitus?
- A.
A. Dehydration
- B.
B. Positive glucose clearance
- C.
C. Osmotic dieresis
- D.
D. Hypokalemia
- E.
E. Hyperglycemia
Correct Answer
D. D. HypokalemiaExplanation
In uncontrolled diabetes mellitus, the body is unable to properly regulate blood sugar levels, leading to hyperglycemia (high blood sugar levels). This can cause osmotic diuresis, where excess glucose in the urine pulls water out of the body, leading to dehydration. Positive glucose clearance refers to the body's attempt to remove excess glucose from the blood, which would be observed in uncontrolled diabetes. However, hypokalemia (low potassium levels) would not be observed in uncontrolled diabetes mellitus.Rate this question:
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- 3.
The pK’s of 5 weak acids are listed below. Which would be the best physiological buffering system in the plasma?
- A.
A. Weak acid A: pK = 1.6
- B.
B. Weak acid B: pK = 3.5
- C.
C. Weak acid C: pK = 6.8
- D.
D. Weak acid D pK = 9.3
- E.
E. Weak acid E: pK = 10.5
Correct Answer
C. C. Weak acid C: pK = 6.8Explanation
The best physiological buffering system in the plasma would be one that has a pK value closest to the physiological pH of around 7.4. Among the given weak acids, weak acid C has a pK value of 6.8, which is the closest to the physiological pH. Therefore, weak acid C would be the best physiological buffering system in the plasma.Rate this question:
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- 4.
Which of the following is a compensation method for respiratory acidosis?
- A.
A. Hypoventilation
- B.
B. Increased HCO3- excretion
- C.
C. Decreased intracellular buffering of H+ ions
- D.
D. Increased formation of ammonia through glutamine
- E.
E. Inhibition of ADH secretion
Correct Answer
D. D. Increased formation of ammonia through glutamineExplanation
Increased formation of ammonia through glutamine is a compensation method for respiratory acidosis. In respiratory acidosis, there is an accumulation of carbon dioxide in the blood, leading to an increase in H+ ions and a decrease in pH. To compensate for this imbalance, the kidneys increase the production of ammonia through the metabolism of glutamine. Ammonia can then combine with H+ ions to form ammonium, which can be excreted in the urine, helping to restore the acid-base balance in the body.Rate this question:
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- 5.
Which one of the following conditions produces metabolic acidosis?
- A.
A. Partial obstruction of the trachea
- B.
B. Severe vomiting
- C.
C. Inhibition of carbonic anhydrase
- D.
D. Living at high altitude (but not born there)
- E.
E. Excessive ingestion of antacids
Correct Answer
C. C. Inhibition of carbonic anhydraseExplanation
Inhibition of carbonic anhydrase can lead to metabolic acidosis. Carbonic anhydrase is an enzyme that helps convert carbon dioxide and water into carbonic acid, which then dissociates into bicarbonate ions and hydrogen ions. Inhibition of this enzyme disrupts the normal process of acid-base balance, leading to an accumulation of hydrogen ions and a decrease in bicarbonate ions. This imbalance results in metabolic acidosis, where there is an excess of acid in the body. The other options listed do not directly cause metabolic acidosis.Rate this question:
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- 6.
pH [HCO3-] PCO2 a. 7.57 44 50 b. 7.20 8 20 c. 7.52 20 25 d. 7.32 40 80 e. 7.24 25 60 Which patient is suffering from an anxiety-induced panic attack?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
C. C -
- 7.
pH [HCO3-] PCO2 a. 7.57 44 50 b. 7.20 8 20 c. 7.52 20 25 d. 7.32 40 80 e. 7.24 25 60 Which patient is in diabetic ketoacidosis?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
B. B -
- 8.
pH [HCO3-] PCO2 a. 7.57 44 50 b. 7.20 8 20 c. 7.52 20 25 d. 7.32 40 80 e. 7.24 25 60 Which patient has chronic obstructive pulmonary disease?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
D. D -
- 9.
pH [HCO3-] PCO2 a. 7.57 44 50 b. 7.20 8 20 c. 7.52 20 25 d. 7.32 40 80 e. 7.24 25 60 Which patient has suffered from pneumonia for several days?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
D. DExplanation
The patient with a pH of 7.32, [HCO3-] of 40, and PCO2 of 80 is the one who has suffered from pneumonia for several days. This is indicated by the lower pH, which suggests acidosis, and the higher PCO2, which indicates respiratory acidosis. Additionally, the [HCO3-] level is within the normal range, indicating compensation for the acidosis.Rate this question:
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- 10.
In congestive heart failure, edema occurs as a direct result of:
- A.
A. Renal failure
- B.
B. Increased hydrostatic pressure in systemic capillaries
- C.
C. Decreased ADH
- D.
D. Increased plasma oncotic pressure
- E.
E. Increased urine output.
Correct Answer
B. B. Increased hydrostatic pressure in systemic capillariesExplanation
In congestive heart failure, the heart is unable to pump blood effectively, leading to a backup of blood in the systemic capillaries. This causes an increase in hydrostatic pressure, which forces fluid out of the capillaries and into the surrounding tissues, leading to edema. Renal failure, decreased ADH, increased plasma oncotic pressure, and increased urine output are not directly related to the development of edema in congestive heart failure.Rate this question:
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- 11.
A patient suffering from metabolic acidosis will NOT exhibit
- A.
A. An increase in urinary titratable acid
- B.
B. An increase in urinary potassium excretion
- C.
C. An increase in the urinary ammonium concentration
- D.
D. A decrease in urinary bicarbonate excretion
- E.
E. A decrease in urinary pH.
Correct Answer
B. B. An increase in urinary potassium excretionExplanation
Metabolic acidosis is a condition characterized by an accumulation of acid or a loss of bicarbonate in the body, leading to a decrease in blood pH. In order to compensate for this acidosis, the kidneys increase the excretion of acid in the urine. This is done by increasing the production of ammonium ions (NH4+) and titratable acids, which help eliminate acid from the body. Additionally, the kidneys also conserve potassium in order to maintain electrolyte balance. Therefore, it would be expected that a patient with metabolic acidosis would exhibit an increase in urinary titratable acid and urinary ammonium concentration, as well as a decrease in urinary pH. However, urinary potassium excretion would not be increased in this condition.Rate this question:
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- 12.
A patient is severely dehydrated following prolonged diarrhea that lasted several days but was not associated with vomiting. However, malaise and nausea prevented the patient from taking much food and drink during this period. After 3 days of theis diarrhea, the blood values are: pHa = 7.34, [HCO3- = 12mM, PaCO2 = 20mmHg, [Na+] =138mM, [K+] = 4.8mM, [Cl-] = 114mM. The above patient has:
- A.
A. Uncompensated metabolic acidosis
- B.
B. Partially compensated metabolic acidosis
- C.
C. Uncompensated respiratory acidosis
- D.
D. Partially compensated respiratory acidosis
- E.
E. A significantly increased anion gap
Correct Answer
B. B. Partially compensated metabolic acidosisExplanation
The patient is experiencing metabolic acidosis as indicated by the low pH and low bicarbonate levels. The low bicarbonate levels suggest that there is an excess of acid in the body. The low PaCO2 levels indicate that there is some compensation by the respiratory system to try to increase the pH by blowing off more carbon dioxide. However, the compensation is not enough to bring the pH back to the normal range, indicating partial compensation. The other options are not supported by the given information.Rate this question:
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- 13.
A patient is severely dehydrated following prolonged diarrhea that lasted several days but was not associated with vomiting. However, malaise and nausea prevented the patient from taking much food and drink during this period. After 3 days of theis diarrhea, the blood values are: pHa = 7.34, [HCO3- = 12mM, PaCO2 = 20mmHg, [Na+] =138mM, [K+] = 4.8mM, [Cl-] = 114mM. In the above patient, which one of the following would you expect to be decreased?
- A.
A. Plasma [aldosterone]
- B.
B. Plasma [atrial natriuretic peptide]
- C.
C. Plasma [angiotensin II]
- D.
D. Plasma [ADH]
- E.
E. Hematocrit
Correct Answer
B. B. Plasma [atrial natriuretic peptide]Explanation
Prolonged diarrhea can lead to dehydration and loss of fluids, which can cause a decrease in blood volume. This decrease in blood volume stimulates the release of atrial natriuretic peptide (ANP) from the atria of the heart. ANP acts to increase the excretion of sodium and water by the kidneys, helping to restore fluid balance. Therefore, in this patient, it would be expected that the plasma concentration of ANP would be increased, not decreased.Rate this question:
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- 14.
A patient is severely dehydrated following prolonged diarrhea that lasted several days but was not associated with vomiting. However, malaise and nausea prevented the patient from taking much food and drink during this period. After 3 days of theis diarrhea, the blood values are: pHa = 7.34, [HCO3- = 12mM, PaCO2 = 20mmHg, [Na+] =138mM, [K+] = 4.8mM, [Cl-] = 114mM. In the above patient, comparing the relative changes in the volume of various compartments, which statement is correct?
- A.
A. The ICF volume decreases more than the ECF volume.
- B.
B. The packed rbc volume decreases more than the plasma volume.
- C.
C. The ISF volume decreases more than the plasma volume
- D.
D. The volume of all compartments decrease to an equal degree
- E.
E. The plasma volume decreases more than any other volume decreases
Correct Answer
C. C. The ISF volume decreases more than the plasma volumeExplanation
The given blood values indicate metabolic acidosis with a low bicarbonate level (HCO3-) and a low PaCO2. This suggests that there is an excessive loss of bicarbonate due to diarrhea. In response to dehydration, the body tries to maintain plasma volume by shifting fluid from the interstitial fluid (ISF) to the plasma. Therefore, the ISF volume decreases more than the plasma volume. This is supported by the fact that the chloride level (Cl-) is higher than normal, indicating a compensatory shift of chloride from the ISF to the plasma.Rate this question:
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- 15.
Assuming the same capacity, the buffer that is most effective in the body is the one with a pK of:
- A.
A. 6.1
- B.
B. 6.4
- C.
C. 6.7
- D.
D. 6.9
- E.
E. 7.2
Correct Answer
E. E. 7.2Explanation
The buffer that is most effective in the body is the one with a pK of 7.2. This is because the pH of the human body is around 7.4, which is slightly basic. A buffer with a pK close to the pH of the body will be able to resist changes in pH more effectively, as it will be able to accept or donate protons to maintain a stable pH. Therefore, a buffer with a pK of 7.2 would be the most effective in the body.Rate this question:
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- 16.
Acidosis will result from:
- A.
A. Hyperaldosteronism
- B.
B. Renal failure
- C.
C. Intravenous infusion of Ringer-lactate solution
- D.
D. Hypokalemia
- E.
E. Consumption of a large volume of fruit juice.
Correct Answer
B. B. Renal failureExplanation
Renal failure can lead to acidosis because the kidneys are responsible for maintaining the balance of acids and bases in the body. When the kidneys are not functioning properly, they are unable to excrete excess acid from the body, leading to an accumulation of acid in the blood. This can result in a decrease in blood pH, causing acidosis.Rate this question:
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- 17.
pHa PaCO2, mmHg, plasma [HCO3-], mEq/L A. 7.20 73 28 B. 7.55 44 40 C. 7.33 44 45 D. 7.65 25 28 E. 7.45 20 14 Chronic (partially compensated) respiratory alkalosis.
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
E. EExplanation
The given answer is E, which corresponds to a pH of 7.45, PaCO2 of 20 mmHg, and plasma [HCO3-] of 14 mEq/L. In respiratory alkalosis, the pH is elevated (>7.45) and the PaCO2 is decreased (Rate this question:
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- 18.
pHa PaCO2, mmHg, plasma [HCO3-], mEq/L A. 7.20 73 28 B. 7.55 44 40 C. 7.33 44 45 D. 7.65 25 28 E. 7.45 20 14 Acute respiratory acidosis
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
A. AExplanation
A pH of 7.20 indicates acidemia (acidic blood). A PaCO2 of 73 mmHg indicates respiratory acidosis, which is caused by an increase in carbon dioxide levels in the blood. A plasma [HCO3-] of 28 mEq/L indicates compensated metabolic acidosis, which occurs as a compensatory mechanism to maintain pH balance. Therefore, the correct answer is acute respiratory acidosis.Rate this question:
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- 19.
pHa PaCO2, mmHg, plasma [HCO3-], mEq/L A. 7.20 73 28 B. 7.55 44 40 C. 7.33 44 45 D. 7.65 25 28 E. 7.45 20 14 Mixed disturbance
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
D. DExplanation
The given answer "D" is the correct answer because it indicates a pH value of 7.65, which is higher than the normal range of 7.35-7.45. This indicates alkalosis. Additionally, the PaCO2 value of 25 mmHg is lower than the normal range of 35-45 mmHg, indicating respiratory alkalosis. The plasma [HCO3-] value of 28 mEq/L is within the normal range of 22-28 mEq/L, indicating normal bicarbonate levels. Therefore, the combination of alkalosis and low PaCO2 suggests a mixed disturbance.Rate this question:
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- 20.
pHa PaCO2, mmHg, plasma [HCO3-], mEq/L A. 7.20 73 28 B. 7.55 44 40 C. 7.33 44 45 D. 7.65 25 28 E. 7.45 20 14 Acute metabolic alkalosis
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
B. BExplanation
The correct answer is B, which corresponds to a pH of 7.55, a PaCO2 of 44 mmHg, and a plasma [HCO3-] of 40 mEq/L. This combination of values indicates a respiratory compensation for a primary metabolic alkalosis. The elevated pH and HCO3- levels suggest an excess of bicarbonate in the blood, which is characteristic of metabolic alkalosis. The slightly elevated PaCO2 indicates that the respiratory system is compensating by retaining carbon dioxide to try to normalize the pH.Rate this question:
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- 21.
Respiratory compensation for metabolic alkalosis takes 12-24hrs to be fully effective because:
- A.
A. CO2 takes that long to be produced metabolically.
- B.
B. The central chemoreceptors require this time to adapt to the hypercapnia produced by attempts to hypoventilate
- C.
C. It takes 24hrs to increase the CSF pH.
- D.
D. Peripheral chemoreceptors only effectively respond to a decrease in plasma pH.
Correct Answer
B. B. The central chemoreceptors require this time to adapt to the hypercapnia produced by attempts to hypoventilateExplanation
The central chemoreceptors require this time to adapt to the hypercapnia produced by attempts to hypoventilate. This means that it takes time for the chemoreceptors in the brain to adjust to the increased levels of carbon dioxide in the blood, which occurs when someone tries to decrease their breathing rate. Once the central chemoreceptors have adapted, they can effectively stimulate the respiratory system to increase ventilation and compensate for the metabolic alkalosis.Rate this question:
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- 22.
As blood flows through metabolizing tissues the pH decreases. The pH decrease is less than would be predicted from the amount of carbonic acid being generated, primarily because of the buffering by:
- A.
A. Intracellular proteins
- B.
B. Plasma phosphate
- C.
C. Plasma proteins
- D.
D. Hemoglobin
- E.
E. HCO3-/H2CO3 buffer pair
Correct Answer
D. D. HemoglobinExplanation
As blood flows through metabolizing tissues, carbonic acid is generated, which would normally decrease the pH. However, the pH decrease is less than expected because of the buffering effect of hemoglobin. Hemoglobin acts as a buffer by binding to hydrogen ions, preventing them from significantly affecting the pH. This buffering action helps to maintain a relatively stable pH in the blood despite the production of carbonic acid.Rate this question:
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- 23.
Which one of the following statements does NOT correctly describe ammonium handling by the kidneys?
- A.
Ammonium enters the medullary interstitum by diffusion trapping
- B.
The major sources of urinary ammonium is from proximal tubular glutamine metabolism.
- C.
Ammonium enters the proximal tubule lumen in exchange for sodium.
- D.
Glutamine metabolism is stimulated by acidosis and hypokalemia
- E.
Ammonia contributes to the countercurrent multiplication mechanisms resulting in medullary interstitial hyperosmolarity.
Correct Answer
A. Ammonium enters the medullary interstitum by diffusion trappingExplanation
Ammonium enters the medullary interstitium by diffusion trapping.Rate this question:
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- 24.
A patient is suffering from diabetic ketoacidosis (and has not been treated with insulin as yet). Which of the following responses would be observed in this patient?
- A.
A. Hypoventilation
- B.
B. Increased buffering of H+ by plasma proteins
- C.
C. Increased utilization of glucose by skeletal muscle.
- D.
D. Decreased urinary phosphate buffering
- E.
E. Decreased bicarbonate reabsorption
Correct Answer
B. B. Increased buffering of H+ by plasma proteinsExplanation
In diabetic ketoacidosis, there is an accumulation of ketones and acidic byproducts in the blood. To counteract the increased acidity, the body attempts to buffer the excess hydrogen ions (H+) by binding them to plasma proteins. This increased buffering of H+ by plasma proteins helps to maintain the pH balance in the blood. Hypoventilation (option a) is not typically observed in diabetic ketoacidosis. Increased utilization of glucose by skeletal muscle (option c) is not directly related to the acid-base balance. Decreased urinary phosphate buffering (option d) and decreased bicarbonate reabsorption (option e) would actually contribute to the acidosis rather than counteract it.Rate this question:
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- 25.
Patients with congestive heart failure often develop hypokalemia (low plasma [K+]). One mechanism that leads to the development of hypokalemia is:
- A.
A. Decreased tubular fluid flow
- B.
B. ANP-induced K+ reabsorption in the proximal tubule
- C.
C. Lack of insulin
- D.
D. Aldosterone-induced K+ secretion by principal cells
- E.
E. Destruction of cardiac tissue.
Correct Answer
D. D. Aldosterone-induced K+ secretion by principal cellsExplanation
The correct answer is d. Aldosterone-induced K+ secretion by principal cells. In patients with congestive heart failure, there is an activation of the renin-angiotensin-aldosterone system. Aldosterone acts on the principal cells of the collecting ducts in the kidneys, increasing the reabsorption of sodium and promoting the secretion of potassium. This leads to an increase in urinary potassium excretion and ultimately results in hypokalemia (low plasma [K+]).Rate this question:
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- 26.
A 15-yr old girl develops nephritic syndrome. Kf is greatly increased; the net negative charge on the glomerular basement membrane is lost. Which parameter is LEAST affected in nephritic syndrome?
- A.
A. GFR
- B.
B. Filtered load of protein.
- C.
C. Urine excretion
- D.
D. Tm for glucose transport in the proximal tubule
- E.
E. Composition of the urine.
Correct Answer
D. D. Tm for glucose transport in the proximal tubuleExplanation
In nephritic syndrome, the glomerular basement membrane becomes more permeable, leading to increased filtration of protein. This results in a higher filtered load of protein and increased urine excretion. Glomerular filtration rate (GFR) may also be affected, as it is a measure of the rate at which fluid is filtered through the glomerulus. However, the transport maximum (Tm) for glucose transport in the proximal tubule is least affected because it is a separate process from the filtration of protein and does not depend on the integrity of the glomerular basement membrane. Therefore, the correct answer is d. Tm for glucose transport in the proximal tubule.Rate this question:
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- 27.
In a patient suffering from metabolic acidosis, which compensation does not occur?
- A.
A. Buffering of H+ by intracellular proteins
- B.
B. Movement of K+ from the interstitium into muscle cells.
- C.
C. Hyperventilation
- D.
D. Increased reabsorption of K+ by intercalated cells
- E.
E. Increased formation of ammonia and ammonium ions.
Correct Answer
B. B. Movement of K+ from the interstitium into muscle cells.Explanation
In metabolic acidosis, the body tries to compensate by buffering excess H+ ions with intracellular proteins (option a), increasing the respiratory rate (hyperventilation) to remove CO2 (option c), and increasing the formation of ammonia and ammonium ions to excrete excess acid (option e). The movement of K+ from the interstitium into muscle cells (option b) is not a compensation mechanism for metabolic acidosis. Therefore, option b is the correct answer.Rate this question:
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Mar 21, 2023Quiz Edited by
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