Deck 10: Acid-Base Regulation

Question 1

A young, previously healthy drug overdose victim with severely depressed ventilation enters the emergency room with the following arterial blood gases: pH = 7.22, PaCO₂ = 70 mm Hg, HCO₃^-= 28 mEq/L.What is the acid-base disturbance of this victim?

A) Uncompensated respiratory acidosis
B) Compensated respiratory acidosis
C) Uncompensated respiratory alkalosis
D) Uncompensated metabolic acidosis

Answer 1

Uncompensated respiratory acidosis

Question 2

What is the function of buffers?

A) They force H⁺ to go inside the cell.
B) They readily combine with HCO₃^-, removing H⁺ from solution.
C) They readily combine with H⁺ ions, removing them from solution.
D) They increase the HCO₃^- concentration in plasma.

Answer 2

They readily combine with H⁺ ions, removing them from solution.

Question 3

Which of the following variables are computed by the H-H equation?
I.pK
II.pH
III.HCO₃^-
IV.PCO₂

A) I, II
B) III, IV
C) II, IV
D) II, III, IV

Answer 3

II, III, IV

Question 4

Which of the following organs is responsible for the physical removal of H⁺?

A) Kidneys
B) Lungs
C) Intestine
D) Pancreas

Question 5

Which of the following is considered a rapid compensatory mechanism to restore the pH back to normal levels in the presence of a metabolic acidosis?

A) CO₂ retention
B) CO₂ elimination
C) HCO₃^- retention
D) HCO₃^- elimination

Question 6

Which of the following statements are true of acid excretion?
I.The lungs excrete only volatile acid.
II.The lungs can excrete large quantities of CO₂ in minutes.
III.The kidneys excrete primarily fixed acids.
IV.The kidneys remove fixed acids at a much slower pace (hours to days).

A) II, III, IV
B) I, II, III, IV
C) II, IV
D) I, II, III

Question 7

Which of the following systems has the greatest buffering capacity?

A) Hb
B) HCO₃^-
C) Organic phosphates
D) Plasma proteins

Question 8

According to the widely accepted Brønsted-Lowry theory, what is an acid?

A) Any substance that donates an electron (H⁺) to an aqueous solution
B) Any substance that donates a proton (H⁺) to an aqueous solution
C) Any substance that accepts a proton (H⁺), removing it from solution
D) Any substance that accepts an electron (H⁺), removing it from solution

Question 9

What is the pH of a chemically neutral solution?

A)6.5
B)7.0
C)7.5
D)8.0

Question 10

In general, when the nonbicarbonate buffer concentration is normal, an acute PaCO? rise to a level of 60 mm Hg will be associated with which of the following changes in the [HCO??]?

A) [HCO3-] rises to approximately 34 mEq/L.
B) [HCO3-] rises to approximately 31 mEq/L.
C) [HCO3-] rises to approximately 26 mEq/L.
D) [HCO3-] rises to approximately 25 mEq/L.

Question 11

Because pH is a logarithmic scale, it is anticipated that a change of one pH unit will result in what change in [H⁺]?

A) Twofold change
B) Fivefold change
C) Tenfold change
D) Twentyfold change

Question 12

In general, when the nonbicarbonate buffer concentration is normal, an acute PaCO₂ rise of 10 mm Hg will be associated with which of the following changes?

A) [HCO₃^-] rises by approximately 10 mEq/L.
B) [HCO₃^-] rises by approximately 5 mEq/L.
C) [HCO₃^-] rises by approximately 2 mEq/L.
D) [HCO₃^-] rises by approximately 1 mEq/L.

Question 13

In general, when the nonbicarbonate buffer concentration is normal, an acute PaCO₂ decrease of 10 mm Hg below 40 mm Hg will be associated with which of the following changes?

A) [HCO3-] decreases by approximately 10 mEq/L.
B) [HCO3-] decreases by approximately 5 mEq/L.
C) [HCO3-] decreases by approximately 2 mEq/L.
D) [HCO3-] decreases by approximately 1 mEq/L.

Question 14

What is the normal ratio of [HCO₃^-] to dissolved CO₂ necessary to maintain a pH of 7.40?

A) 10:1
B) 20:1
C) 30:1
D) 40:1

Question 15

Which of the following are the major mechanisms responsible for maintaining a stable pH in the face of massive CO₂ production?
I.Proteins
II.Ventilation
III.Isohydric buffering
IV.HCO₃^-

A) I, II, III
B) III, IV
C) I, II, III, IV
D) II, III

Question 16

According to the widely accepted Brønsted-Lowry theory, what is a base?

A) Any substance that donates an electron (H⁺) to an aqueous solution
B) Any substance that donates a proton (H⁺) to an aqueous solution
C) Any substance that accepts a proton (H⁺), removing it from solution
D) Any substance that accepts an electron (H⁺), removing it from solution

Question 17

Which of the following is the only volatile acid of physiological significance in the body?

A) Carbonic acid
B) Lactic acid
C) Phosphoric acid
D) Sulfuric acid

Question 18

Which of the following nonbicarbonate buffers is the most important?

A) Hb
B) HCO₃^-
C) Organic phosphates
D) Plasma proteins

Question 19

Which of the following disturbances in the pH may potentially occur in patients with nasogastric suction catheters?

A) Respiratory alkalosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Metabolic acidosis

Question 20

Which of the following are examples of a fixed acid?
I.Carbonic acid
II.Lactic acid
III.Phosphoric acid
IV.Sulfuric acid

A) I, II
B) III, IV
C) II, IV
D) II, III, IV