Hall: Guyton and Hall Textbook of Medical Physiology, 12th Edition
Chapter 44: Physiology of Deep-Sea Diving and Other Hyperbaric Conditions
Test Bank
1. A diver is breathing 21% O2 while suspended motionless at a depth of 99 feet. What is
the alveolar pO2?
A. 100 mmHg
B. 149 mmHg
C. 419 mmHg
D. 578 mmHg
E. 3,000 mmHg
ANS: D
2. Which of the following occurs during scuba diving?
Alveolar pO2 Alveolar pCO2 Peripheral Chemoreceptor Activity
A. ↑ ↔ ↔
B. ↔ ↔ ↔
C. ↓ ↔ ↑
D. ↓ ↓ ↓
E. ↓ ↓ ↑
F. ↔ ↓ ↑
3. The partial pressure of oxygen in dry air (21% O2) inhaled by divers at a depth of 100
feet below sea level (4 atmospheres) is approximately:
A. 160 mm Hg
B. 320 mm Hg
C. 640 mm Hg
D. 1,280 mm Hg
4. Regarding a healthy recreational scuba diver at a depth of 66 feet in the Caribbean Sea,
which statement is true?
A. Her lungs are smaller than normal
B. She has an elevated arterial pO2 and a normal pCO2
C. All gas partial pressures in her blood (oxygen, nitrogen, carbon dioxide and water
vapor) are elevated
D. There are increases in both fraction of inspired oxygen (FiO2) and inspired nitrogen
(FiN2)
Test Bank
44-2
5. A scuba diver is diving from the surface to 100 ft. He has an increase in cardiac output
from 5 to15 L/min. As he swims downward, the blood flow in the base of his lungs will
be in ______ and at the apex will be at ______.
A. Zone III, zone III
B. Zone II, zone II
C. Zone I, zone III
D. Zone II, zone II
6. A 44-year-old male is scuba diving at 60 feet and loses track of the time. Upon return to
the surface he notices pain in his knees. This pain is the result of:
A. Nitrogen narcosis
B. Excess generation of oxygen free radicals
C. Decompression sickness
D. Increase arterial pCO2
7. A scuba diver at a depth of 130 feet below the surface of the ocean has a minute
respiratory volume of 5 L/min. Expressed as a sea level equivalent, the rate of air use
from his tank is:
A. 5 L/min
B. 10 L/min
C. 15 L/min
D. 25 L/min
8. A diver at a depth of 500 feet will have a normal tidal volume to:
A. Remove carbon dioxide from the blood
B. To remove excess nitrogen
C. Allow adequate diffusion of oxygen to blood
D. To prevent collapse of the lungs
ANS: A
9. At a depth of 100 feet, a scuba diver inhales fully to achieve a lung volume of 6 liters. As
he rises to the surface, he continually exhales so that when he gets to the surface he still
has a lung volume of 6 liters. How much air did he exhale?
A. 2 liters
B. 10 liters
C. 14 liters
D. 18 liters
Test Bank
44-3
10. A person is scuba diving at 100 feet breathing compressed air. What is the approximate
alveolar pCO2?
A. 10 mmHg
B. 20 mmHg
C. 40 mmHg
D. 80 mmHg
E. 160 mmHg
11. A diver is breathing 10% O2 at a pressure of 1,500 mmHg. The diver’s body temperature
is 37 C, and pCO2 = 32 mmHg. What is the alveolar pO2?
A. 63 mmHg
B. 105 mmHg
C. 150 mmHg
D. 203 mmHg