Question 1

According to Dalton’s Law, what determines the partial pressure of a gas in a mixture?

Accepted Answer

The proportion of the gas in the mixture multiplied by the total pressure

Question 2

A patient is exposed to carbon monoxide (CO) poisoning. Which property of hemoglobin explains why CO is so dangerous?

Accepted Answer

CO binds to hemoglobin with a much higher affinity than oxygen, preventing oxygen transport

Question 3

Which equation best represents the reversible binding of oxygen to hemoglobin in red blood cells?

Accepted Answer

$\mathrm{HHb} + \mathrm{O}_2 \rightleftharpoons \mathrm{HbO}_2$

Question 4

During exercise, which of the following respiratory adjustments occurs to meet increased metabolic demands?

Accepted Answer

Ventilation increases 10 to 20 fold, but arterial $\mathrm{PO}_2$ and pH remain relatively stable

Question 5

Which of the following is the primary mechanism for CO$_2$ transport in the blood?

Accepted Answer

As bicarbonate ion ($\mathrm{HCO}_3^-$) in plasma

Question 6

A patient with emphysema has enlarged alveolar chambers and reduced lung elasticity. What is the most direct consequence for gas exchange?

Accepted Answer

Reduced surface area and impaired gas exchange efficiency

Question 7

Which law explains why nitrogen bubbles can form in the blood during rapid ascent from deep water (decompression sickness)?

Accepted Answer

Henry’s Law

Question 8

If the partial pressure of oxygen in alveoli is 104 mm Hg and in pulmonary arteries is 40 mm Hg, what direction will oxygen diffuse?

Accepted Answer

From alveoli into pulmonary arteries

Question 9

Which of the following factors will increase the rate of oxygen unloading from hemoglobin at the tissues?

Accepted Answer

Increased $\mathrm{P}_{CO_2}$ and decreased pH

Question 10

A patient is experiencing hypoxia due to cyanide poisoning. What is the underlying cause?

Accepted Answer

Cells unable to use oxygen despite adequate delivery

Question 11

Which equation represents the conversion of CO$_2$ to bicarbonate in red blood cells?

Accepted Answer

$\mathrm{CO}_2 + \mathrm{H}_2\mathrm{O} \rightleftharpoons \mathrm{H}_2\mathrm{CO}_3 \rightleftharpoons \mathrm{HCO}_3^- + \mathrm{H}^+$

Question 12

Which respiratory center in the brainstem is primarily responsible for setting the basic rhythm of breathing?

Accepted Answer

Ventral respiratory group (VRG)

Question 13

A climber at high altitude experiences acute mountain sickness. What is the physiological reason for this?

Accepted Answer

Lower atmospheric pressure and reduced $\mathrm{PO}_2$

Question 14

Which of the following is a homeostatic response to chronic bronchitis?

Accepted Answer

Fibrosis and narrowing of lower airways

Question 15

Which type of lung cancer originates in the peripheral lung areas and is most common?

Accepted Answer

Adenocarcinoma

Question 16

What is the effect of hyperventilation on blood CO$_2$ levels and pH?

Accepted Answer

CO$_2$ levels decrease and pH increases

Question 17

Which of the following best describes perfusion-ventilation coupling in the lungs?

Accepted Answer

Air flow to alveoli is matched to blood flow for optimal gas exchange

Question 18

A patient with asthma experiences airway constriction due to inflammation. Which immune response is primarily involved?

Accepted Answer

Release of interleukins, IgE production, and recruitment of inflammatory cells

Question 19

Which chemoreceptors are most sensitive to changes in blood CO$_2$ and pH?

Accepted Answer

Peripheral chemoreceptors in the carotid artery and aortic arch

Question 20

Which of the following is a long-term adaptation to high altitude?

Accepted Answer

Increased red blood cell numbers and hemoglobin concentration

The Respiratory System: Gas Exchange, Transport, and Regulation

Study Guide - Practice Questions