50 Analytical Multiple Choice Questions on Acid Base Balance with Explanation- Part 4

 

31. What is the primary mechanism by which the lungs regulate acid-base balance?

a) Excretion of bicarbonate

b) Conversion of CO₂ into carbonic acid

c) Regulation of oxygen levels

d) Control of carbon dioxide excretion

Answer: d) Control of carbon dioxide excretion

Explanation: The lungs regulate acid-base balance by controlling the exhalation of carbon dioxide (CO₂), which directly affects the concentration of carbonic acid in the blood and, consequently, the pH.

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32. Which of the following conditions is most likely to lead to metabolic alkalosis?

a) Lactic acidosis

b) Hypoaldosteronism

c) Chronic vomiting

d) Diabetic ketoacidosis

Answer: c) Chronic vomiting

Explanation: Chronic vomiting leads to the loss of gastric acid (hydrochloric acid), which reduces hydrogen ion concentration in the body and causes a relative increase in bicarbonate, resulting in metabolic alkalosis.

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33. What is the expected blood pH in a patient with fully compensated metabolic acidosis?

a) Less than 7.35

b) Between 7.35 and 7.45

c) Greater than 7.45

d) Unpredictable without knowing bicarbonate levels

Answer: b) Between 7.35 and 7.45

Explanation: In fully compensated metabolic acidosis, the pH is restored to normal range (7.35-7.45) due to respiratory compensation, which involves hyperventilation to reduce CO₂ and lower carbonic acid concentration.

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34. How does hyperkalemia affect the acid-base balance?

a) It leads to respiratory acidosis

b) It causes intracellular alkalosis

c) It induces metabolic acidosis

d) It has no significant effect on acid-base balance

Answer: c) It induces metabolic acidosis

Explanation: Hyperkalemia can lead to metabolic acidosis because high levels of potassium cause a shift of hydrogen ions out of cells, increasing extracellular hydrogen ion concentration and lowering blood pH.

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35. Which of the following is a key feature of mixed acid-base disorders?

a) Normal pH with abnormal PCO₂ and HCO₃⁻

b) High pH with low bicarbonate

c) Low pH with elevated PCO₂ and bicarbonate

d) Consistent patterns of PCO₂ and bicarbonate changes

Answer: a) Normal pH with abnormal PCO₂ and HCO₃⁻

Explanation: In mixed acid-base disorders, compensatory mechanisms may lead to a normal pH, but the underlying disorder can cause abnormal PCO₂ and bicarbonate levels. This combination of abnormalities indicates multiple concurrent disturbances.

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36. In the context of acid-base balance, what is the function of carbonic anhydrase in red blood cells?

a) Conversion of CO₂ into bicarbonate

b) Conversion of bicarbonate into carbon dioxide

c) Buffering hydrogen ions directly

d) Facilitating the binding of oxygen to hemoglobin

Answer: a) Conversion of CO₂ into bicarbonate

Explanation: Carbonic anhydrase catalyzes the reversible conversion of carbon dioxide (CO₂) and water into carbonic acid, which then dissociates into bicarbonate and hydrogen ions. This reaction is crucial for CO₂ transport and acid-base balance.

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37. Which of the following conditions would most likely cause a low anion gap?

a) Multiple myeloma

b) Salicylate toxicity

c) Diabetic ketoacidosis

d) Lactic acidosis

Answer: a) Multiple myeloma

Explanation: A low anion gap can occur in multiple myeloma due to the presence of abnormal proteins (e.g., paraproteins) that increase the concentration of unmeasured cations, thereby reducing the anion gap.

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38. Which of the following is the most effective renal response to chronic metabolic acidosis?

a) Increased excretion of hydrogen ions

b) Increased reabsorption of sodium ions

c) Decreased reabsorption of potassium ions

d) Decreased excretion of hydrogen ions

Answer: a) Increased excretion of hydrogen ions

Explanation: In response to chronic metabolic acidosis, the kidneys increase the excretion of hydrogen ions and reabsorb more bicarbonate to help neutralize the excess acid and restore normal blood pH.

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39. A patient with metabolic alkalosis is likely to experience which of the following electrolyte imbalances?

a) Hyperkalemia

b) Hypernatremia

c) Hypokalemia

d) Hypercalcemia

Answer: c) Hypokalemia

Explanation: Metabolic alkalosis is often associated with hypokalemia, as the shift of hydrogen ions out of cells leads to an influx of potassium ions into cells, reducing the extracellular potassium concentration.

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40. In which of the following situations is a patient likely to develop respiratory acidosis?

a) Pulmonary embolism

b) Panic attack

c) Chronic obstructive pulmonary disease (COPD)

d) High-altitude exposure

Answer: c) Chronic obstructive pulmonary disease (COPD)

Explanation: COPD impairs the ability to exhale CO₂, leading to its accumulation in the blood and resulting in respiratory acidosis.

50 Analytical Multiple Choice Questions on Acid Base Balance with Explanation- Part 1

50 Analytical Multiple Choice Questions on Acid Base Balance with Explanation- Part 2 

50 Analytical Multiple Choice Questions on Acid Base Balance with Explanation- Part 3

50 Analytical Multiple Choice Questions on Acid Base Balance with Explanation- Part 4 

50 Analytical Multiple Choice Questions on Acid Base Balance with Explanation- Part 5