Deck 12: Acid-Base Balance During Exercise

Question 1

Which of the following plays the most important role in acid-base balance during exercise?

A) respiratory system
B) kidneys
C) both a and b
D) neither a nor b

Answer 1

A

Question 2

Muscle pH is generally

A) 0.4-0.6 pH units lower than blood pH.
B) 0.4-0.6 pH units higher than blood pH.
C) equal to blood pH.

Answer 2

A

Question 3

Carbon dioxide is considered an acid because it

A) directly liberates H⁺ when it enters the plasma.
B) is rapidly converted to lactic acid.
C) can react with water to form carbonic acid, which dissociates to release H⁺.
D) none of the above.

Answer 3

C

Question 4

The bicarbonate buffer system results in the stimulation of ventilation.

Question 5

The first line of defense in protecting against pH change during exercise is

A) sodium bicarbonate supplementation.
B) blood buffers.
C) intracellular buffers.
D) plasma bicarbonate.

Question 6

The most important of the blood buffers is/are

A) bicarbonate.
B) blood proteins.
C) hemoglobin.
D) platelets.

Question 7

Sodium bicarbonate has been ingested by athletes in an attempt to improve performance by

A) increasing blood buffering capacity.
B) decreasing muscle lactate production.
C) stimulating pulmonary ventilation to increase oxygen transport.
D) increasing plasma volume.

Question 8

An example of a strong base is bicarbonate (HCO₃^-).

Question 9

Metabolic acidosis is a result of the overproduction of ketoacids, which can occur

A) during exercise.
B) in uncontrolled diabetes.
C) as a result of high levels of glucose metabolism.
D) all of the above.

Question 10

Which of the following is true of the pH of arterial blood?

A) The normal pH is 7.0.
B) A pH of 7.0 would be considered acidosis.
C) A pH of 7.0 would be considered alkalosis.
D) None of the above is true.

Question 11

Acidosis could be due to

A) a decrease in the H⁺ concentration.
B) a loss of acids from the blood.
C) an accumulation of bases in the blood.
D) none of the above.

Question 12

Acids are defined as

A) molecules that release hydroxyl ions (OH^-).
B) molecules that release hydrogen ions (H⁺).
C) molecules that combine with hydrogen ions.
D) substances that raise the hydrogen ion concentration of the solution.

Question 13

The most common and strongest acid produced in skeletal muscle during heavy exercise is ________________ acid.

A) phosphoric
B) lactic
C) acetoacetic
D) citric

Question 14

One of the principal means by which the kidneys regulate acid-base balance is by increasing or decreasing the bicarbonate concentration of the blood.

Question 15

The respiratory system works in the regulation of acid-base balance by lowering the blood tension of

A) O₂.
B) CO₂.
C) HCO₃.
D) H₂CO₃.

Question 16

Which of the intracellular buffers contributes the most to the cell's buffering capacity?

A) muscle bicarbonate
B) intracellular phosphate groups
C) intracellular proteins
D) all of the above contribute equally

Question 17

Which of the following sports would have the greatest risk of acid-base disturbance?

A) baseball
B) 100-m sprint
C) 800-m run
D) 10,000-m run

Question 18

Which of the following events occurs at approximately 50-60% VO₂ max?

A) a decrease in plasma bicarbonate concentration
B) an increase in blood lactic acid concentration
C) a decrease in blood pH
D) all of the above

Question 19

An increase in the hydrogen ion concentration in contracting skeletal muscle can impair performance by hydrogen ions competing with calcium ions for binding sites on troponin.

Question 20

The principal buffer against acidosis during exercise is intracellular phosphate groups.

Question 21

A lack of the enzyme carbonic anhydrase would affect the ability of the body to both buffer the blood and to transport CO₂.