Question 1

Which of the following equations correctly represents the equilibrium for the carbonic acid-bicarbonate buffer system in blood?

Accepted Answer

$$\mathrm{CO_2$ + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons $$HCO_3$$^- + H^+}$$

Question 2

A patient is experiencing hyperventilation. How does this affect the blood pH, according to the carbonic acid-bicarbonate buffer equilibrium?

Accepted Answer

Blood pH increases (alkalosis) because $$\mathrm{CO_2$} is $$removed, shifting equilibrium left and decreasing $$\mathrm{H^+}.$$

Question 3

Which component acts as the conjugate base in the carbonic acid-bicarbonate buffer system?

Accepted Answer

$$\mathrm{$$HCO_3$$^-}$$

Question 4

If a patient’s blood becomes too acidic, which direction will the equilibrium shift to minimize the change in pH?

Accepted Answer

The equilibrium shifts left, converting $$\mathrm{H^+}$$ and $$\mathrm{$$HCO_3$$^-}$$ into $$\mathrm{H_2CO_3}$$ and then $$\mathrm{CO_2$}$$ and $$\mathrm{H_2O}.$$

Question 5

Which of the following best describes the role of the carbonic acid-bicarbonate buffer system in blood?

Accepted Answer

It resists changes in pH by neutralizing added acids or bases through reversible reactions.

Question 6

A person holds their breath for an extended period. What is the expected effect on blood pH and why?

Accepted Answer

Blood pH decreases (acidosis) because $$\mathrm{CO_2$}$$ accumulates, shifting equilibrium right and increasing $$\mathrm{H^+}.$$

Question 7

Which equation represents the Henderson-Hasselbalch equation for the bicarbonate buffer system?

Accepted Answer

$$\mathrm{pH = p}K_a + \log \left( \dfrac{[$$HCO_3$$^-]}{[H_2CO_3]} \right)$$

Question 8

Which of the following scenarios would most likely result in metabolic alkalosis?

Accepted Answer

Excessive vomiting, leading to loss of gastric acid and increased $$\mathrm{$$HCO_3$$^-} in $$blood.

Question 9

If the concentration of $$\mathrm{$$HCO_3$$^-} in $$blood decreases significantly, what is the expected effect on blood pH?

Accepted Answer

Blood pH decreases, leading to metabolic acidosis.

Question 10

Which of the following best explains why the carbonic acid-bicarbonate buffer system is effective in blood?

Accepted Answer

It is in equilibrium with atmospheric $$\mathrm{CO_2$}$$, allowing rapid adjustment via respiration.

Question 11

A patient with chronic lung disease has elevated $$\mathrm{CO_2$}$$ levels. What acid-base disorder are they most at risk for?

Accepted Answer

Respiratory acidosis

Question 12

Which of the following changes would shift the equilibrium $$\mathrm{CO_2$ + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons $$HCO_3$$^- + H^+} to $$the right?

Accepted Answer

Increasing $$\mathrm{CO_2$}$$ concentration

Question 13

Which physiological process is primarily responsible for removing excess $$\mathrm{CO_2$}$$ from the body to help maintain pH balance?

Accepted Answer

Exhalation via the respiratory system

Question 14

A patient is given an intravenous solution containing sodium bicarbonate ($$\mathrm{$$NaHCO_3$$}). $$What is the expected effect on blood pH?

Accepted Answer

Blood pH increases due to increased $$\mathrm{$$HCO_3$$^-}$$, shifting equilibrium left and reducing $$\mathrm{H^+}.$$

Question 15

Which of the following best describes the effect of hypoventilation on the carbonic acid-bicarbonate buffer system?

Accepted Answer

It increases $$\mathrm{CO_2$}$$, shifting equilibrium right and increasing $$\mathrm{H^+}$$, causing acidosis.

Acid-Base Equilibria and the Bicarbonate Buffer System in Blood

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