The detergent-like substance that keeps the alveoli from collapsing between breaths because it reduces the surface tension of the water film in the alveoli is called:
a. Lecithin
b. Bile
c. Surfactant
d. Reluctant
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The detergent-like substance that keeps the alveoli from collapsing between breaths because it reduces the surface tension of the water film in the alveoli is called:
a. Lecithin
b. Bile
c. Surfactant
d. Reluctant
Oxygen and carbon dioxide are exchanged in the lungs and through all cell membranes by:
a. Active transport
b. Diffusion
c. Filtration
d. Osmosis
When the inspiratory muscles contract:
a. The size of the thoracic cavity increases in diameter
b. The size of the thoracic cavity increases in length
c. The volume of the thoracic cavity decreases
d. The size of the thoracic cavity increases in both length and diameter
Which of the following determines the direction of gas movement?
a. Solubility in water
b. Partial pressure gradient
c. Temperature
d. Molecular weight and size of the gas molecule
Most oxygen carried in the blood is:
a. In solution in the plasma
b. Combined with plasma proteins
c. Chemically combined with the heme in red blood cells
d. In solution in the red blood cells
Which of the following has the greatest stimulating effect on the respiratory centers in the brain?
a. Oxygen
b. Carbon dioxide
c. Calcium
d. Willpower