Q: A climber is ascending to 5,000 meters above sea level, where the total atmospheric pressure is 373 mmHg. What is the partial pressure of oxygen ($$P_{O_2$}) at $$this altitude? Use the percentage of oxygen in air as 20.95%.

$$P_{O_2$} = 0.2095 \times 373 = 78.2$$ mmHg

Q: Which equation correctly calculates the partial pressure of a gas in a mixture?

$$P_{gas} = \text{Percentage of gas} \times \text{Total Pressure}$$

Question 1

Which process is primarily responsible for oxygen exchange across the respiratory surface in simple organisms such as the Lake Titicaca frog?

Accepted Answer

Diffusion

Question 2

A climber is ascending to 5,000 meters above sea level, where the total atmospheric pressure is 373 mmHg. What is the partial pressure of oxygen ($$P_{O_2$}) at $$this altitude? Use the percentage of oxygen in air as 20.95%.

Accepted Answer

$$P_{O_2$} = 0.2095 	imes 373 = 78.2$$ mmHg

Question 3

Which statement best describes the role of bulk flow in mammalian lungs?

Accepted Answer

Bulk flow is responsible for moving air in and out of the lungs during ventilation.

Question 4

During inspiration, which direction does air move in relation to pressure gradients?

Accepted Answer

From an area of high pressure to an area of low pressure

Question 5

A diver descends to 20 meters underwater, where the pressure is 3 times normal atmospheric pressure. If the diver breathes air (not pure oxygen), what happens to the solubility of gases in their blood?

Accepted Answer

Solubility of gases increases with increased pressure.

Question 6

Why do divers get 'the bends' when ascending too quickly from deep water?

Accepted Answer

Rapid ascent causes nitrogen to come out of solution and form bubbles in tissues.

Question 7

Which equation correctly calculates the partial pressure of a gas in a mixture?

Accepted Answer

$$P_{gas} = 	ext{Percentage of gas} 	imes 	ext{Total Pressure}$$

Question 8

Which of the following best explains why ventilation is necessary in complex animals?

Accepted Answer

Ventilation moves the respiratory medium across the respiratory surface, maintaining a pressure gradient for diffusion.

Question 9

If the tidal volume ($$V_T) of a $$person is 500 mL, what does this value represent?

Accepted Answer

The amount of air moved into or out of the lungs with each breath

Question 10

Which of the following scenarios would result in the greatest decrease in partial pressure of oxygen ($$P_{O_2$}) in $$the alveoli?

Accepted Answer

Ascending to high altitude without supplemental oxygen

Question 11

A patient is experiencing impaired diffusion across the alveolar membrane. Which of the following is most likely to occur?

Accepted Answer

Decreased oxygen exchange between alveoli and blood

Question 12

Which law explains the relationship between the solubility of a gas in a liquid and pressure, as seen in SCUBA diving?

Accepted Answer

Henry's Law

Question 13

During normal expiration, which muscles are primarily involved?

Accepted Answer

Internal intercostal muscles and diaphragm relax

Question 14

Which of the following would most likely increase the rate of diffusion of oxygen across the respiratory membrane?

Accepted Answer

Increasing the partial pressure gradient of oxygen

Question 15

If a person is breathing air at sea level ($$P_{atm} = 760$$ mmHg), what is the partial pressure of nitrogen ($$P_{N_2$}) $$given that nitrogen makes up 79.02% of air?

Accepted Answer

$$P_{N_2$} = 0.7902 	imes 760 = 600.6$$ mmHg

Question 16

Which of the following is NOT a factor that affects gas exchange efficiency at the respiratory surface?

Accepted Answer

Color of the respiratory surface

Question 17

A patient with pulmonary edema has fluid accumulation in the alveoli. How does this affect gas exchange?

Accepted Answer

It decreases the efficiency of gas exchange due to increased diffusion distance.

Question 18

Which of the following best describes the difference between convection (bulk flow) and diffusion in respiratory physiology?

Accepted Answer

Convection moves the respiratory medium over the surface, while diffusion moves gases across the membrane.

Question 19

Which of the following would most likely occur if a mammal's ventilation rate decreases significantly?

Accepted Answer

Partial pressure of carbon dioxide in the alveoli would increase.

Respiratory Physiology: Mechanisms of Gas Exchange and Transport

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