Which row of the table describes the best overall conditions for gas exchange in the lungs?
Surface Area Diffusion Pathway Concentration Gradient
A. Large
Long
Steep
B. Large
Short
Steep
C. Large
Short
Shallow
D. Small
Short
Shallow
Choose your answer A B C D
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Which row of the table shows the events of inspiration in the correct sequence?
1 2 3 4
A. Diaphragm and external intercostal muscles contract
Volume of thorax increases
Thorax pressure drops
Air is drawn into the lungs down its pressure gradient
B. Thorax expands
Thorax pressure drops
Diaphragm and external intercostal muscles contract
Volume of thorax increases
C. Air is drawn into the lungs down its pressure gradient
Diaphragm and external intercostal muscles contract
Thorax pressure drops
Volume of thorax increases
D. Thorax pressure drops
Volume of thorax increases
Thorax expands
Air is drawn into the lungs down its pressure gradient
Choose your answer A B C D
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Which of the following is a feature of forced expiration?
The thorax undergoes a drop in pressure.
The internal intercostal muscles contract.
The external intercostal muscles contract.
Choose your answer A B C D
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Which aspects of ventilation are assisted by the solution secreted by type II pneumocytes?
Dissolving of oxygen gas.
Recoil of alveolar walls during expiration.
Preventing alveoli from collapsing.
Diffusion of carbon dioxide gas into the alveoli.
Choose your answer A B C D
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Patients with emphysema are often prescribed oxygen cylinders to breathe from. The oxygen concentration in a cylinder is around 90%, compared to 21% in atmospheric air.
How does breathing concentrated oxygen increase the effectiveness of the lungs?
Increases concentration gradient.
Assists expiration of stale air.
Decreases diffusion pathway.
Choose your answer A B C D
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