BIOL 252 Module 5: The Respiratory System -
Practice Exam LATEST 2026 REAL!!!
This exam covers the anatomy, physiology, and pathophysiology of the respiratory system, including
critical thinking questions that integrate knowledge from the module.
Question 1
Which of the following is the primary function of the type II alveolar cells?
a) To form the thin, delicate walls of the alveoli for gas exchange.
b) To engulf foreign particles and debris in the alveoli.
c) To secrete pulmonary surfactant to reduce surface tension.
d) To line the respiratory tract with cilia to move mucus.
• Rationale: Type I alveolar cells are the structural cells responsible for gas exchange. Alveolar
macrophages (dust cells) perform phagocytosis. Type II alveolar cells secrete surfactant, a
soapy substance that lowers the surface tension of the alveolar fluid, preventing alveolar
collapse .
Question 2
During a severe asthma attack, bronchiolar smooth muscle constricts, and mucus plugs the airways. This
directly leads to:
a) An increase in tidal volume.
b) An increase in airway resistance and a decrease in airflow.
c) A significant decrease in anatomical dead space.
d) An increase in the partial pressure of oxygen in the alveoli.
• Rationale: Asthma is an obstructive lung disease. The narrowing of the airways due to
bronchoconstriction and inflammation increases resistance. According to basic physics, as
resistance increases, airflow decreases for a given pressure gradient. This impedes ventilation .
Question 3
A patient presents with a deficiency of oxygen at the tissue level. This condition is clinically defined as:
a) Hypocapnia
b) Hypercapnia
,c) Anoxia
d) Hypoxia
• Rationale: The question provides the textbook definition of hypoxia. Hypocapnia is a deficiency
of carbon dioxide in the blood, while hypercapnia is an excess of carbon dioxide. Anoxia refers
to the complete absence of oxygen .
Question 4
Which of the following represents the correct pathway of a molecule of oxygen from the nose to the
alveolus?
a) Nasal cavity, pharynx, larynx, trachea, bronchiole, bronchus, alveolus
b) Nasal cavity, pharynx, larynx, trachea, primary bronchus, secondary bronchus, bronchiole, alveolus
c) Nasal cavity, larynx, pharynx, trachea, bronchus, bronchiole, alveolus
d) Nasal cavity, pharynx, larynx, trachea, bronchus, bronchiole, alveolus
• Rationale: Air enters through the nasal cavity, then moves to the pharynx (throat), then the
larynx (voice box), down the trachea (windpipe), into a bronchus, then into smaller
bronchioles, and finally into the alveoli where gas exchange occurs. Option B incorrectly lists
"bronchiole" before "bronchus" .
Question 5
The enzyme carbonic anhydrase, found in red blood cells, catalyzes a reaction vital for gas transport.
What is the primary importance of this reaction?
a) It allows oxygen to bind more readily to hemoglobin.
b) It enables blood to transport a large amount of carbon dioxide in the form of bicarbonate ions.
c) It converts carbon monoxide to carbon dioxide for exhalation.
d) It facilitates the breakdown of carbaminohemoglobin.
• Rationale: Carbonic anhydrase catalyzes the reversible reaction: CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ +
HCO₃⁻. This rapid conversion of CO₂ into bicarbonate ions (HCO₃⁻) is the primary method (about
70%) by which carbon dioxide is transported in the blood plasma .
Question 6
If the dorsal respiratory group (DRG) of the medulla oblongata were damaged, a person would most
likely experience:
a) An inability to voluntarily hold their breath.
b) A loss of the Hering-Breuer reflex.
c) A cessation of the basic rhythmic cycle of inspiration.
d) An inability to increase ventilation rate during exercise.
, • Rationale: The DRG contains neurons that generate the basic rhythm of breathing by sending
signals to the inspiratory muscles (diaphragm and external intercostals). Damage to this area
would stop the automatic cycle of inspiration. The ventral respiratory group (VRG) is involved in
forceful breathing, and voluntary control comes from the cerebral cortex .
Question 7
According to Boyle's Law, inhalation occurs when:
a) The diaphragm relaxes, decreasing the volume of the thoracic cavity.
b) The diaphragm contracts, increasing the volume of the thoracic cavity and decreasing intra-alveolar
pressure.
c) Intra-alveolar pressure increases above atmospheric pressure.
d) The partial pressure of oxygen in the alveoli exceeds that in the blood.
• Rationale: Boyle's Law states that pressure and volume are inversely related. When the
diaphragm contracts, the thoracic cavity volume increases. This increase in volume causes the
intra-alveolar pressure to decrease (below atmospheric pressure), creating a pressure gradient
that air follows into the lungs .
Question 8
Which of the following would best explain a significantly low arterial PₐO₂ (partial pressure of oxygen)
but a normal arterial PₐCO₂ (partial pressure of carbon dioxide)?
a) Hypoventilation
b) Impaired gas diffusion across the alveolar membrane (e.g., in pulmonary fibrosis)
c) A significant increase in anatomical dead space
d) Apnea
• Rationale: CO₂ diffuses across the alveolar-capillary membrane about 20 times more readily
than O₂. In conditions like fibrosis, where the membrane thickens, oxygen diffusion is impaired
first, leading to low blood O₂ (hypoxemia). CO₂, diffusing so easily, can still be eliminated
normally, so blood CO₂ levels remain normal until the condition is very severe .
Question 9
The majority of oxygen is transported in the blood:
a) Dissolved directly in the plasma.
b) As bicarbonate ions.
c) Bound to the iron ion within the heme group of hemoglobin.
d) As carbaminohemoglobin.
• Rationale: Oxygen is not very soluble in plasma (option A). Bicarbonate ions (option B) and
carbaminohemoglobin (option D) are methods of carbon dioxide transport. Approximately
Practice Exam LATEST 2026 REAL!!!
This exam covers the anatomy, physiology, and pathophysiology of the respiratory system, including
critical thinking questions that integrate knowledge from the module.
Question 1
Which of the following is the primary function of the type II alveolar cells?
a) To form the thin, delicate walls of the alveoli for gas exchange.
b) To engulf foreign particles and debris in the alveoli.
c) To secrete pulmonary surfactant to reduce surface tension.
d) To line the respiratory tract with cilia to move mucus.
• Rationale: Type I alveolar cells are the structural cells responsible for gas exchange. Alveolar
macrophages (dust cells) perform phagocytosis. Type II alveolar cells secrete surfactant, a
soapy substance that lowers the surface tension of the alveolar fluid, preventing alveolar
collapse .
Question 2
During a severe asthma attack, bronchiolar smooth muscle constricts, and mucus plugs the airways. This
directly leads to:
a) An increase in tidal volume.
b) An increase in airway resistance and a decrease in airflow.
c) A significant decrease in anatomical dead space.
d) An increase in the partial pressure of oxygen in the alveoli.
• Rationale: Asthma is an obstructive lung disease. The narrowing of the airways due to
bronchoconstriction and inflammation increases resistance. According to basic physics, as
resistance increases, airflow decreases for a given pressure gradient. This impedes ventilation .
Question 3
A patient presents with a deficiency of oxygen at the tissue level. This condition is clinically defined as:
a) Hypocapnia
b) Hypercapnia
,c) Anoxia
d) Hypoxia
• Rationale: The question provides the textbook definition of hypoxia. Hypocapnia is a deficiency
of carbon dioxide in the blood, while hypercapnia is an excess of carbon dioxide. Anoxia refers
to the complete absence of oxygen .
Question 4
Which of the following represents the correct pathway of a molecule of oxygen from the nose to the
alveolus?
a) Nasal cavity, pharynx, larynx, trachea, bronchiole, bronchus, alveolus
b) Nasal cavity, pharynx, larynx, trachea, primary bronchus, secondary bronchus, bronchiole, alveolus
c) Nasal cavity, larynx, pharynx, trachea, bronchus, bronchiole, alveolus
d) Nasal cavity, pharynx, larynx, trachea, bronchus, bronchiole, alveolus
• Rationale: Air enters through the nasal cavity, then moves to the pharynx (throat), then the
larynx (voice box), down the trachea (windpipe), into a bronchus, then into smaller
bronchioles, and finally into the alveoli where gas exchange occurs. Option B incorrectly lists
"bronchiole" before "bronchus" .
Question 5
The enzyme carbonic anhydrase, found in red blood cells, catalyzes a reaction vital for gas transport.
What is the primary importance of this reaction?
a) It allows oxygen to bind more readily to hemoglobin.
b) It enables blood to transport a large amount of carbon dioxide in the form of bicarbonate ions.
c) It converts carbon monoxide to carbon dioxide for exhalation.
d) It facilitates the breakdown of carbaminohemoglobin.
• Rationale: Carbonic anhydrase catalyzes the reversible reaction: CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ +
HCO₃⁻. This rapid conversion of CO₂ into bicarbonate ions (HCO₃⁻) is the primary method (about
70%) by which carbon dioxide is transported in the blood plasma .
Question 6
If the dorsal respiratory group (DRG) of the medulla oblongata were damaged, a person would most
likely experience:
a) An inability to voluntarily hold their breath.
b) A loss of the Hering-Breuer reflex.
c) A cessation of the basic rhythmic cycle of inspiration.
d) An inability to increase ventilation rate during exercise.
, • Rationale: The DRG contains neurons that generate the basic rhythm of breathing by sending
signals to the inspiratory muscles (diaphragm and external intercostals). Damage to this area
would stop the automatic cycle of inspiration. The ventral respiratory group (VRG) is involved in
forceful breathing, and voluntary control comes from the cerebral cortex .
Question 7
According to Boyle's Law, inhalation occurs when:
a) The diaphragm relaxes, decreasing the volume of the thoracic cavity.
b) The diaphragm contracts, increasing the volume of the thoracic cavity and decreasing intra-alveolar
pressure.
c) Intra-alveolar pressure increases above atmospheric pressure.
d) The partial pressure of oxygen in the alveoli exceeds that in the blood.
• Rationale: Boyle's Law states that pressure and volume are inversely related. When the
diaphragm contracts, the thoracic cavity volume increases. This increase in volume causes the
intra-alveolar pressure to decrease (below atmospheric pressure), creating a pressure gradient
that air follows into the lungs .
Question 8
Which of the following would best explain a significantly low arterial PₐO₂ (partial pressure of oxygen)
but a normal arterial PₐCO₂ (partial pressure of carbon dioxide)?
a) Hypoventilation
b) Impaired gas diffusion across the alveolar membrane (e.g., in pulmonary fibrosis)
c) A significant increase in anatomical dead space
d) Apnea
• Rationale: CO₂ diffuses across the alveolar-capillary membrane about 20 times more readily
than O₂. In conditions like fibrosis, where the membrane thickens, oxygen diffusion is impaired
first, leading to low blood O₂ (hypoxemia). CO₂, diffusing so easily, can still be eliminated
normally, so blood CO₂ levels remain normal until the condition is very severe .
Question 9
The majority of oxygen is transported in the blood:
a) Dissolved directly in the plasma.
b) As bicarbonate ions.
c) Bound to the iron ion within the heme group of hemoglobin.
d) As carbaminohemoglobin.
• Rationale: Oxygen is not very soluble in plasma (option A). Bicarbonate ions (option B) and
carbaminohemoglobin (option D) are methods of carbon dioxide transport. Approximately
