$$P_{gas} = F_{gas} \times P_{total}$$

Question 1

Which of the following best describes the role of alveolar macrophages in the respiratory system?

Accepted Answer

They engulf and remove debris and pathogens from the alveolar spaces.

Question 2

A patient with chronic obstructive pulmonary disease (COPD) is likely to experience which of the following physiological changes?

Accepted Answer

Irreversible decrease in ability to force air out of the lungs due to loss of elastic recoil.

Question 3

Which equation correctly represents the reversible reaction catalyzed by carbonic anhydrase in red blood cells?

Accepted Answer

$$CO_2 + H_2O$$ \leftrightarrow H_2CO_3 \leftrightarrow $$HCO_3^- + H$$^+$$

Question 4

During inspiration, which pressure change occurs in the pleural cavity to facilitate lung expansion?

Accepted Answer

Pleural pressure becomes more negative, dropping below atmospheric pressure.

Question 5

Which of the following statements about hemoglobin and oxygen transport is correct?

Accepted Answer

Hemoglobin releases oxygen more readily in metabolically active tissues due to increased $$CO_2$$ and lower pH.

Question 6

A climber at high altitude experiences a decrease in arterial $$PO_2. $$Which physiological response helps maintain oxygen delivery to tissues?

Accepted Answer

Increased respiratory rate and depth to enhance oxygen uptake.

Question 7

Which of the following best explains why $$CO_2 is $$transported primarily as bicarbonate ($$HCO_3$$^-$$) in the blood?

Accepted Answer

Bicarbonate is more soluble in plasma than $$CO_2$$ gas.

Question 8

Which formula represents the calculation of partial pressure of a gas in a mixture?

Accepted Answer

$$P_{gas} = F_{gas} 	imes P_{total}$$

Question 9

A patient is hyperventilating. What effect does this have on blood pH and why?

Accepted Answer

Blood pH increases due to excessive loss of $$CO_2.$$

Question 10

Which of the following is a direct effect of surfactant in the alveoli?

Accepted Answer

It decreases alveolar surface tension, preventing collapse during expiration.

Question 11

Which of the following best describes the Bohr effect in hemoglobin?

Accepted Answer

Hemoglobin binds oxygen more tightly at higher pH.

Question 12

Which structure is primarily responsible for detecting changes in blood $$CO_2$$ and pH to regulate breathing rate?

Accepted Answer

Chemoreceptors in the carotid and aortic bodies

Question 13

A patient with impaired ciliary function in the respiratory tract is at increased risk for which of the following?

Accepted Answer

Accumulation of mucus and increased susceptibility to infection.

Question 14

Which of the following is the correct sequence of events during external respiration?

Accepted Answer

Oxygen diffuses from alveoli to blood; carbon dioxide diffuses from blood to alveoli.

Question 15

Which of the following best explains why oxygen is less soluble in plasma compared to carbon dioxide?

Accepted Answer

Oxygen forms fewer hydrogen bonds with water molecules.

Question 16

Which of the following equations represents the conversion of hemoglobin to oxyhemoglobin?

Accepted Answer

$$Hb + O_2$ \rightarrow $$HbO_2$$

Question 17

A patient with respiratory acidosis is likely to have which of the following blood gas findings?

Accepted Answer

Increased $$CO_2$$ and decreased pH.

Question 18

Which of the following is a major function of the conducting zone in the respiratory system?

Accepted Answer

Filtering, warming, and humidifying incoming air.

Question 19

Which of the following best describes the effect of increased temperature on the oxygen-hemoglobin dissociation curve?

Accepted Answer

Curve shifts to the right, decreasing hemoglobin affinity for oxygen.

Question 20

Which of the following is the primary reason why $$CO_2 is $$more efficiently transported in the blood than $$O_2$$?

Accepted Answer

$$CO_2 is $$more soluble in plasma and can be converted to bicarbonate.

Respiratory System: Physiology, Gas Exchange, and Pathology

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