Question 1

Which of the following is the primary buffer system in the plasma that is most effective due to the ability of the lungs to regulate one of its components?

Accepted Answer

Bicarbonate buffer system

Question 2

A patient with chronic kidney disease presents with metabolic acidosis. Laboratory results show a decreased plasma bicarbonate and an increased anion gap. Which of the following is the correct formula for calculating the anion gap?

Accepted Answer

$$AG = [Na^+] - ([Cl^-] + [$$HCO_3$$^-])$$

Question 3

Which of the following best explains why hypokalemia can lead to metabolic alkalosis?

Accepted Answer

Low potassium increases H+ secretion in the renal tubules, making urine more acidic and body fluids more alkaline.

Question 4

A patient is hyperventilating due to anxiety. Which acid-base disturbance is most likely to develop, and what is the expected change in arterial blood gases?

Accepted Answer

Respiratory alkalosis; decreased $$PCO_2$$ and increased pH

Question 5

Which of the following is a major source of hydrogen ions in the body?

Accepted Answer

Carbon dioxide metabolism forming carbonic acid

Question 6

A patient with severe diarrhea is found to have a normal anion gap metabolic acidosis. What is the most likely mechanism?

Accepted Answer

Loss of bicarbonate-rich fluids from the gastrointestinal tract

Question 7

Which of the following best describes the role of hemoglobin in acid-base balance?

Accepted Answer

Hemoglobin acts as a major non-bicarbonate buffer in erythrocytes, buffering hydrogen ions produced during CO2 transport.

Question 8

A patient with chronic obstructive pulmonary disease (COPD) develops respiratory acidosis. Which of the following best explains the underlying pathophysiology?

Accepted Answer

Decreased elimination of CO2 through the lungs increases $$PCO_2$$, lowering blood pH.

Question 9

Which of the following buffer systems is most important in the urine and intracellular fluid, but contributes only about 5% of the nonbicarbonate buffer value of plasma?

Accepted Answer

Phosphate buffer system

Question 10

A patient with diabetic ketoacidosis presents with rapid, deep breathing (Kussmaul respiration). Which compensatory mechanism is being activated?

Accepted Answer

Respiratory compensation to decrease $$PCO_2$$ and raise pH

Question 11

Which of the following best describes the effect of hyperkalemia on acid-base balance?

Accepted Answer

Hyperkalemia decreases H+ excretion, contributing to acidosis.

Question 12

Which of the following is a direct effect of increased respiratory rate and depth on acid-base status?

Accepted Answer

Decreased $$PCO_2$$ and increased pH

Question 13

A patient with severe vomiting is at risk for which acid-base disturbance, and what is the primary mechanism?

Accepted Answer

Metabolic alkalosis due to loss of acid-rich gastric fluids

Question 14

Which of the following is a function of the renal Na+-H+ exchanger in acid-base balance?

Accepted Answer

It extrudes H+ into the tubular fluid in exchange for Na+, helping to excrete acid.

Question 15

Which of the following best explains why the bicarbonate buffer system is so effective in the body?

Accepted Answer

The lungs can rapidly regulate $$CO_2$$, a component of the system, allowing quick compensation.

Question 16

A patient with lactic acidosis is found to have an increased anion gap. Which of the following best explains the increase in the anion gap?

Accepted Answer

Accumulation of unmeasured anions such as lactate in the plasma

Question 17

Which of the following is a common cause of respiratory alkalosis due to direct stimulation of the respiratory center?

Accepted Answer

Anxiety or hysteria

Question 18

Which of the following best describes the role of ammonia in renal acid-base regulation?

Accepted Answer

Ammonia is produced from glutamine, diffuses into the tubular lumen, and combines with H+ to form ammonium ions for excretion.

Question 19

A patient with methanol poisoning develops metabolic acidosis. Which of the following best describes the type of acidosis and the expected anion gap?

Accepted Answer

Increased anion gap metabolic acidosis

Question 20

Which of the following is a characteristic of protein buffer systems in plasma?

Accepted Answer

Albumin, via its imidazole groups, provides significant buffering capacity in plasma.

Hydrogen Ion Metabolism and Acid-Base Balance: Microbiology and Physiology Context

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