Q: According to Dalton’s Law, what is the partial pressure of oxygen ($$P_{O_2$}) in a $$mixture of gases if the total pressure is 760 mm Hg and oxygen makes up 21% of the mixture?

$$P_{O_2$} = 0.21 \times 760 = 159.6 mm Hg$$

Question 1

Which of the following best describes the primary function of the nasal conchae in the upper respiratory system?

Accepted Answer

They increase the mucosal surface area to filter, heat, and moisten incoming air.

Question 2

A patient inhales a small object that becomes lodged in the right primary bronchus. Which anatomical feature explains why this is more likely to occur in the right bronchus than the left?

Accepted Answer

The right primary bronchus is wider, shorter, and more vertical than the left.

Question 3

Which of the following equations correctly represents Boyle’s Law as it applies to pulmonary ventilation?

Accepted Answer

$$P_1$$ $$V_1$$ = $$P_2$$ $$V_2$$

Question 4

During quiet inspiration, which muscles contract to increase thoracic volume?

Accepted Answer

Diaphragm and external intercostals

Question 5

A patient with emphysema has a reduced surface area for gas exchange. Which of the following is most likely to be affected as a result?

Accepted Answer

The rate of oxygen diffusion into the blood

Question 6

Which of the following best explains why surfactant is essential for normal lung function?

Accepted Answer

It reduces alveolar surface tension, preventing alveolar collapse during expiration.

Question 7

A spirometry test shows a patient has a decreased vital capacity (VC) but a normal total lung capacity (TLC). Which type of pulmonary disorder is most likely present?

Accepted Answer

Obstructive pulmonary disorder

Question 8

According to Dalton’s Law, what is the partial pressure of oxygen ($$P_{O_2$}) in a $$mixture of gases if the total pressure is 760 mm Hg and oxygen makes up 21% of the mixture?

Accepted Answer

$$P_{O_2$} = 0.21 	imes 760 = 159.6 mm Hg$$

Question 9

Which of the following changes would most likely shift the oxygen-hemoglobin dissociation curve to the right, enhancing oxygen unloading at the tissues?

Accepted Answer

Increased temperature, increased $$P_{CO_2$}$$, and decreased pH

Question 10

Which of the following best describes the Haldane effect?

Accepted Answer

Deoxygenated hemoglobin binds more CO$$_2$$, facilitating CO$$_2$$ transport from tissues to lungs.

Question 11

A person at high altitude experiences an increase in ventilation rate and erythropoietin production. What is the physiological reason for these changes?

Accepted Answer

Lower atmospheric $$P_{O_2$}$$ leads to hypoxemia, stimulating increased breathing and red blood cell production.

Question 12

Which of the following is a protective mechanism of the respiratory system that prevents over-inflation of the lungs?

Accepted Answer

The Hering-Breuer reflex

Question 13

Which of the following best explains why a patient with chronic bronchitis is at increased risk for respiratory infections?

Accepted Answer

Excess mucus production and inflammation impair ciliary function, reducing the ability to clear pathogens.

Question 14

Which of the following statements about the pleurae is correct?

Accepted Answer

The pleurae produce fluid that lubricates the lungs, allowing friction-free movement during breathing.

Question 15

A patient is exposed to carbon monoxide (CO). Which of the following best explains why CO is so dangerous?

Accepted Answer

CO has a much higher affinity for hemoglobin than oxygen, preventing oxygen transport.

Question 16

Which of the following best describes the role of the ventral respiratory group (VRG) in the medulla oblongata?

Accepted Answer

It generates the basic rhythm of breathing by controlling the contraction of the diaphragm and external intercostals.

Question 17

Which of the following best explains why airway resistance is usually insignificant in healthy individuals?

Accepted Answer

The large diameter of upper airways and the high number of small airways in the lower respiratory tract minimize resistance.

Question 18

Which of the following is the correct formula for calculating vital capacity (VC)?

Accepted Answer

$$VC = TV + IRV + ERV$$

Question 19

A patient with metabolic acidosis is breathing rapidly and deeply. Which mechanism best explains this response?

Accepted Answer

Peripheral chemoreceptors detect low pH and stimulate increased ventilation to decrease CO$$_2$$ and raise blood pH.

Chapter 22: The Respiratory System – Functional Anatomy and Physiology

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