Q: Which equation correctly represents the relationship for air flow in the lungs?

$$\text{Air flow} = \frac{\text{atmospheric pressure} - \text{alveolar pressure}}{\text{resistance}}$$

Q: If the fractional concentration of O$$_2 in $$air is 0.21 and the total atmospheric pressure is 760 mm Hg, what is the partial pressure of O$$_2$$?

$$0.21 \times 760 = 159.6 mm Hg$$

Question 1

Which of the following best describes the difference between internal and external respiration?

Accepted Answer

Internal respiration is the use of O$$_2$$ and production of CO$$_2$$ within mitochondria, while external respiration is the exchange of O$$_2$$ and CO$$_2$$ between the atmosphere and body tissues.

Question 2

Which structure is responsible for both air and food passage in the respiratory anatomy?

Accepted Answer

Pharynx

Question 3

What is the primary function of the conducting zone in the respiratory tract?

Accepted Answer

Humidifying and warming air as it moves from the larynx to the lungs

Question 4

Why does the thinness of the alveolar wall facilitate gas exchange?

Accepted Answer

It decreases the distance gases must diffuse, allowing for rapid exchange of O$$_2$$ and CO$$_2.$$

Question 5

According to Boyle's Law, what happens to the pressure of a gas if the volume of its container is doubled, assuming temperature and amount of gas are constant?

Accepted Answer

Pressure is halved

Question 6

During inspiration, which of the following occurs?

Accepted Answer

Inspiratory muscles contract, increasing alveolar volume and decreasing alveolar pressure below atmospheric pressure

Question 7

Which equation correctly represents the relationship for air flow in the lungs?

Accepted Answer

$$	ext{Air flow} = \frac{	ext{atmospheric pressure} - 	ext{alveolar pressure}}{	ext{resistance}}$$

Question 8

A patient is experiencing hypoventilation. What changes would you expect in their arterial blood gases?

Accepted Answer

Decreased PO$$_2$$ and increased PCO$$_2$$

Question 9

Which of the following best explains why gas exchange occurs in the respiratory zone and not the conducting zone?

Accepted Answer

The conducting zone has thicker walls, preventing efficient diffusion of gases.

Question 10

If the fractional concentration of O$$_2 in $$air is 0.21 and the total atmospheric pressure is 760 mm Hg, what is the partial pressure of O$$_2$$?

Accepted Answer

$$0.21 	imes 760 = 159.6 mm Hg$$

Question 11

During hyperventilation, what happens to the partial pressures of O$$_2$$ and CO$$_2 in $$the arteries?

Accepted Answer

PO$$_2$$ increases and PCO$$_2$$ decreases

Question 12

Which of the following mechanisms increases alveolar ventilation during hyperpnea?

Accepted Answer

Increasing either the volume or frequency of breaths, or both

Question 13

Which of the following is NOT a component of external respiration?

Accepted Answer

Cellular use of O$$_2$$ and production of CO$$_2 in $$mitochondria

Question 14

What is the driving force for air movement during pulmonary ventilation?

Accepted Answer

The difference between alveolar pressure and atmospheric pressure

Question 15

Which of the following best describes the movement of gases across the respiratory membrane?

Accepted Answer

Gases move down their partial pressure gradients from higher to lower pressure

Question 16

A person is exercising vigorously. Which term best describes the increase in alveolar ventilation to meet tissue demand?

Accepted Answer

Hyperpnea

Question 17

Which of the following statements about the alveoli is correct?

Accepted Answer

Alveoli have a high density and thin walls to maximize surface area and facilitate gas exchange.

Question 18

Which of the following is true regarding the mechanics of breathing during expiration?

Accepted Answer

Inspiratory muscles relax, and alveolar pressure increases above atmospheric pressure.

Question 19

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

Accepted Answer

$$	ext{Partial pressure} = 	ext{Fractional concentration} 	imes 	ext{Total pressure}$$

Bio 2160 Ch.12

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