Respiratory - from West's 8th ed Chapter 1 - Structure & Function

Question 1

Concerning the blood-gas barrier of the human lung:

A. The thinnest part of the blood-gas barrier has a thickness of about 3 µm.
B. The total area of the blood-gas barrier is about 1 square meter.
C. About 10% of the area of the alveolar wall is occupied by capillaries.
D. If the pressure in the capillaries rises to unphysiologically high levels, the blood-gas barrier can be damaged.
E. Oxygen crosses the blood-gas barrier by active transport.

Answer 1

D

Question 2

When oxygen moves through the thin side of the blood-gas barrier from the alveolar gas to the hemoglobin of the red blood cell, it traverses the following layers in order:

A. Epithelial cell, surfactant, interstitium, endothelial cell, plasma, red cell membrane.
B. Surfactant, epithelial cell, interstitium, endothelial cell, plasma, red cell membrane.
C. Surfactant, endothelial cell, interstitium, epithelial cell, plasma, red cell membrane.
D. Epithelium cell, interstitium, endothelial cell, plasma, red cell membrane.
E. Surfactant, epithelial cell, interstitium, endothelial cell, red cell membrane.

Answer 2

B

Question 3

What is the PO2 (in mm Hg) of moist inspired gas of a climber on the summit of Mt. Everest (assume barometric pressure is 247 mm Hg)?

A. 32
B. 42
C. 52
D. 62
E. 72

Answer 3

B

Question 4

Concerning the airways of the human lung:

A. The volume of the conducting zone is about 50 ml.
B. The volume of the rest of the lung during resting conditions is about 5 liters.
C. A respiratory bronchiole can be distinguished from a terminal bronchiole because the latter has alveoli in its walls.
D. On the average, there are about three branchings of the conducting airways before the first alveoli appear in their walls.
E. In the alveolar ducts the predominant mode of gas flow is diffusion rather than convection.

Answer 4

E

Question 5

Concerning the blood vessels of the human lung:

A. The pulmonary veins form a branching pattern that matches that of the airways.
B. The average diameter of the capillaries is about 50 µm.
C. The bronchial circulation has about the same blood flow as the pulmonary circulation.
D. On the average, blood spends about 0.75 second in the capillaries under resting conditions.
E. The mean pressure in the pulmonary artery is about 100 mm Hg.

Answer 5

D