Chapter 41 Which is the following occurs with carbon monoxide

Hall: Guyton and Hall Textbook of Medical Physiology, 12th Edition

Chapter 41: Regulation of Respiration

Test Bank

1. Five hours after an uneventful knee surgery, a conscious 50-year-old woman has minor

heart pains and a decrease in systolic blood pressure from 110 to 90 mmHg. Arterial

blood gas analysis on her breathing room air shows:

pH 7.30

pCO2 52 mmHg

pO2 58 mmHg

Which of the following is the most likely cause of these findings?

A. Alveolar hypoventilation

B. Cardiac failure

C. Hypoxia due to anesthetic gases

D. Pulmonary hypertension

ANS: A

2. Voluntary apnea (breath-holding) for 60 seconds will:

A. Decrease alveolar pCO2

B. Increase arterial pO2

C. Inhibit the arterial chemoreceptors

D. Increase alveolar pCO2

3. Which of the following play a part in the increase in ventilation with moderate exercise?

A. Reflexes from moving limbs

B. Decrease in body temperature

C. Fall in arterial pO2

D. Rise in arterial pCO2

4. A 9-year-old boy decided to find out how long he could breathe into and out of a paper

bag. After ~2 minutes his friends noticed that he was breathing very rapidly and forced

him to stop. Which of the following was the most potent stimulus for the boy’s

hyperventilation?

A. Decreased arterial PO2

B. Increased arterial PO2

C. Increased arterial PCO2

D. Decreased arterial PCO2

E. Increased pH

Test Bank

41-2

5. Which of the following conditions would be expected to stimulate the arterial

chemoreceptors?

A. Mild anemia

B. Normal breathing

C. Hypoxia due to ascent to high altitude

D. Hyperventilation

E. Exposure to carbon monoxide

6. Hyperventilation will result FROM:

A. A decrease in arterial pCO2 to less than 30 mmHg

B. Direct stimulation of the medulla chemosensitive area caused by an increase in pH

C. An increase in alveolar pCO2

D. An increase in alveolar PO2

7. Which of the following would result in a decrease in nerve activity from the peripheral

chemoreceptors?

A. A decrease in arterial oxygen content

B. A decrease in blood pH

C. A decrease in arterial blood pressure

D. An increase in arterial pO2

8. While playing ball, a child fell and injured his head, producing a lesion in the respiratory

center. As a result, he is hypoventilating. Twenty minutes after the accident the data that

would best fit his condition are:

pH pCO2 pO2

A. 7.50 30 60

B. 7.35 60 100

C. 7.25 60 60

D. 7.30 70 80

E. 7.40 50 90

9. The main reason that respiratory compensation occurs in metabolic acidosis is due to

stimulation of:

A. The carotid bodies by CO2

B. The carotid bodies by H+

C. The central chemoreceptors by CO2

Test Bank

41-3

D. The central chemoreceptors by H+

E. The central chemoreceptors by O2

10. Which is the following occurs with carbon monoxide inhalation?

Alveolar pO2 Alveolar pCO2 Peripheral Chemoreceptor Activity

A. ↑ ↔ ↔

B. ↔ ↔ ↔

C. ↓ ↔ ↑

D. ↓ ↓ ↓

E. ↓ ↓ ↑

F. ↔ ↓ ↑

11. During moderate aerobic exercise:

A. Arterial pO2 increases

B. Arterial pCO2 increases

C. Arterial pH increases

D. Blood lactate level decreases

12. Peripheral and central chemoreceptors may both contribute to the increased ventilation

that occurs as a result of:

A. A decrease in arterial oxygen content

B. A decrease in arterial blood pressure

C. An increase in arterial carbon dioxide tension

D. A decrease in arterial oxygen tension

E. An increase in arterial pH