Question 1

Which of the following best describes the relationship between hydrogen ion concentration and pH, as shown on the logarithmic pH scale?

Accepted Answer

A decrease of 1 pH unit corresponds to a tenfold increase in hydrogen ion concentration.

Question 2

A patient’s arterial blood pH is measured at 7.45, while their venous blood pH is 7.35. What is the most likely explanation for this difference?

Accepted Answer

Venous blood contains more carbon dioxide, which forms carbonic acid and lowers its pH.

Question 3

Which equation correctly represents the formation of carbonic acid in red blood cells, as catalyzed by carbonic anhydrase?

Accepted Answer

$$\mathrm{CO_2$ + H_2O \rightarrow H_2CO_3}$$

Question 4

Which buffer pair is primarily responsible for maintaining blood pH, and what is their normal ratio?

Accepted Answer

Sodium bicarbonate and carbonic acid; 20:1

Question 5

If a patient is experiencing metabolic acidosis, which of the following changes would you expect in their blood chemistry?

Accepted Answer

A deficit of sodium bicarbonate ($$\mathrm{$$NaHCO_3$$})$$

Question 6

Which mechanism acts immediately to prevent sharp changes in blood pH when acids or bases are added?

Accepted Answer

Chemical/buffer mechanism

Question 7

During hyperventilation, which acid-base disturbance is most likely to occur?

Accepted Answer

Respiratory alkalosis

Question 8

Which of the following best describes the action of a buffer in blood?

Accepted Answer

Buffers prevent sharp changes in pH by neutralizing added acids or bases.

Question 9

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

Accepted Answer

Metabolic alkalosis due to excess bicarbonate

Question 10

Which of the following equations represents the dissociation of a strong acid in water?

Accepted Answer

$$\mathrm{HCl \rightarrow H^+ + Cl^-}$$

Question 11

Which organ is the most effective regulator of blood pH, and how does it accomplish this?

Accepted Answer

Kidneys, by secreting hydrogen ions and reabsorbing bicarbonate

Question 12

If the ratio of sodium bicarbonate to carbonic acid in blood changes from 20:1 to 10:1, what is the likely effect on blood pH?

Accepted Answer

Blood pH will decrease, causing acidosis.

Question 13

Which of the following is a fixed acid that does not break down to form a gas and is buffered mainly by sodium bicarbonate?

Accepted Answer

Lactic acid

Question 14

What compensatory mechanism is activated when blood pH drops due to increased CO2 production during exercise?

Accepted Answer

Increased respiratory rate

Question 15

Which of the following best describes the effect of the respiratory mechanism on blood pH?

Accepted Answer

Respirations remove CO2, decreasing carbonic acid and increasing blood pH.

Question 16

A patient with emphysema is most likely to develop which acid-base disturbance?

Accepted Answer

Respiratory acidosis

Question 17

Which of the following best explains why large pH fluctuations may appear small on the pH scale?

Accepted Answer

The pH scale is logarithmic, so each unit represents a tenfold change in H+ concentration.

Question 18

Which of the following is NOT a mechanism that helps maintain pH homeostasis in body fluids?

Accepted Answer

Digestive mechanism

Question 19

Which acid-base disturbance is most likely in a patient with uncontrolled diabetes and prolonged diarrhea?

Accepted Answer

Metabolic acidosis

Question 20

In compensated metabolic acidosis, what happens to the ratio of sodium bicarbonate to carbonic acid?

Accepted Answer

The ratio remains at 20:1, but the total amounts of both decrease.

Acid-Base Balance: Mechanisms and Clinical Implications

Study Guide - Practice Questions