Egan Ch. 12

What is the most important component in the O2 transport system?

• Dissolved O2 in ml/dl

• HCO3–

• Hb

• PaO2

During normal inspiration, which of the following occurs?

• Alveoli at the apexes expand less than those at the bases.

• Alveoli at the apexes expand more than those at the bases.

• Alveoli at the bases and apexes expand almost equally.

• Alveoli at the bases expand less than those at the apexes.

Which condition causes an increase in alveolar dead space?

• Absorption atelectasis

• Blockage of pulmonary circulation

• Increase in anatomic dead space

• Pulmonary vasodilation

Calculate the approximate PAO2 given the following conditions (assume R = 0.8): FiO2 = .40, PB = 770 mm Hg, PACO2 = 31 mm Hg

• 100 mm Hg

• 135 mm Hg

• 250 mm Hg

• 723 mm Hg

What is the approximate normal level of carbon dioxide production (CO2) for an adult?

• 200 ml/min

• 250 ml/min

• 4200 ml/min

• 2000 ml/min

Which of the following “layers” must be traversed by gases moving across the alveolar-capillary membrane?

1. Alveolar epithelial membrane

2. Capillary endothelial membrane

3. Interstitial space

4. Transbronchial radial tethering mechanisms

• 1, 2, 3

• 1, 2, 4

• 2, 3

• All the above

What is the normal range of PAO2 – PaO2 for healthy young adults breathing room air?

• 5 to 10 mm Hg

• 10 to 20 mm Hg

• 20 to 30 mm Hg

• 50 to 60 mm Hg

The PAO2 depends on which of the following factors?

1. Ambient (atmospheric) pressure

2. Fractional concentration of inspired O2

3. Level of VA

4. Types of fuels burned (fat, protein, and carbohydrate)

• 1, 2, 3

• 2, 3, 4

• 3, 4

• all the above

The expected PaO2 for an 80-year-old man who is otherwise in good health and breathing room air is approximately what level?

• 50 mm Hg

• 75 mm Hg

• 80 mm Hg

• 90 mm Hg

When a Hb molecule accumulates excessive amounts of HCO3–, it is expelled from the cell in exchange for Cl–. What is this called?

• Bohr effect

• Haldane effect

• Hamburger phenomenon

• Hydrolysis phenomenon