Chapter 43 Relative to sea level residents who have been

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

Chapter 43: Aviation, High-Altitude, and Space Physiology

Test Bank

1. Which of the following sets of data best describe a normal person breathing air at an

altitude of 18,000 ft?

pO2 pCO2 Saturation Arterial pH

A. 500 35 85% 7.4

B. 28 30 60% 7.5

C. 120 25 99% 7.2

D. 33 80 45% 7.0

E. 124 50 98% 7.35

2. An astronaut is exercising in space. He has an increase in cardiac output from 4 to 15

L/min. Blood flow in his lungs would be in ______ at rest and ______ during exercise.

A. Zone III, zone III

B. Zone II, zone II

C. Zone I, zone III

D. Zone II, zone II

3. A tourist left New York and flew to Switzerland to climb Mt. Blanc in the Swiss Alps,

which is 15,771 feet above sea level, barometric pressure = 420 mmHg. His physician

had suggested that he take acetazolamide, a carbonic anhydrase inhibitor before and

throughout his trip. IF he had taken this what would be the expected response?

A. Return of pH to normal

B. Normal ventilation

C. Hypoventilation

D. Normal arterial blood gases

4. Upon their return to earth after two weeks in space, an astronaut will exhibit:

A. An increased blood pressure

B. An increased urinary output

C. A decreased muscle tone

D. An elevated cardiac output

E. A normal blood volume

Test Bank

43-2

5. Which of the following will return toward normal during acclimatization to high altitude

(12,000 ft)?

A. Arterial carbon dioxide tension

B. Arterial hydrogen ion concentration

C. Arterial hemoglobin concentration

D. Alveolar ventilation

6. Compared with normal values at sea level, an acute (two-hour) expose to high altitude

(15,000 ft) will result in which of the following?

A. Increase in blood hemoglobin to 22 g%

B. Decrease in arterial pCO2

C. Blood acidosis

D. Normal arterial oxygen saturation

7. Between sea level and 10,000 ft altitude, which of the following will not different?

A. Fractional percentage of O2

B. Inspired pO2

C. Dissolved O2 in the blood

D. Dissolved CO2 in the blood

8. Relative to sea level residents who have been at altitude for three days, high altitude

natives have a lower:

A. Systemic arterial pCO2

B. Systemic arterial pO2

C. Systemic arterial O2 bound to hemoglobin

D. Resistance to O2 diffusion in the lungs

9. A person is flying at 6,000 ft (barometric pressure 638 mmHg) in an unpressurized

airplane, breathing air. If alveolar ventilation is normal what would be his arterial pO2?

A. 50 mmHg

B. 60 mmHg

C. 75 mmHg

D. 85 mmHg

E. 99 mmHg

Test Bank

43-3

10. In an acclimatized person at high altitudes, oxygen delivery to the tissues may be

adequate at rest because of:

A. An increase in hemoglobin concentration

B. The presence of an acidosis

C. A decrease in the number of tissue capillaries

D. The presence of a normal arterial pO2

E. The presence of a lower-than-normal arterial pCO2

11. A pilot is flying a pressured commercial airplane at 35,000 ft and is breathing normal air.

There will be:

A. A hypoxic vasoconstriction in his/her lungs

B. A decrease in his/her alveolar pCO2

C. An increase in his/her arterial pO2

D. A hyperventilation due to increased PCO2

E. A normal ventilation and normal blood gases

12. A non-acclimatized person is breathing air at an altitude of 15,000 ft (barometric pressure

= 483). The person is walking and has a doubled alveolar ventilation and a doubled

metabolism. What is the pO2 in the alveoli?

A. 42

B. 66

C. 91

D. 152

E. 383