ATI CRITICAL ALTERATIONS IN GAS EXCHANGE:
COMPREHENSIVE EXAM QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A
SECTION 1: RESPIRATORY ANATOMY & PHYSIOLOGY (15 Questions)
1. Which structure creates the greatest portion of the pressure gradient that
drives inspiration?
A. External intercostal muscles
B. Diaphragm
C. Internal intercostal muscles
D. Scalenes
Correct Answer: B
Rationale: Contraction of the diaphragm flattens the dome, increasing thoracic volume
and decreasing intrapleural pressure, which is the primary driver of inspiration.
2. Surfactant primarily affects which of the following lung properties?
A. Elastic recoil
B. Airway resistance
C. Lung compliance
D. Diffusion capacity
Correct Answer: C
Rationale: Surfactant reduces surface tension within alveoli, increasing lung
compliance and making expansion easier. It is required to keep the alveoli from
collapsing and causing atelectasis.
3. Which process refers to the movement of oxygen and carbon dioxide between
the alveoli and the pulmonary capillaries?
,A. Ventilation
B. Diffusion
C. Perfusion
D. Oxygenation
Correct Answer: B
Rationale: Diffusion is the passive movement of gases (oxygen and carbon dioxide)
across the alveolar-capillary membrane down their concentration gradients, driven by
partial pressure differences between the alveoli and blood.
4. A nurse is reviewing the mechanics of breathing. Which muscle is the primary
muscle of inspiration?
A. Internal intercostal muscles
B. Diaphragm
C. Abdominal muscles
D. Sternocleidomastoid
Correct Answer: B
Rationale: The diaphragm is the primary muscle of inspiration; when it contracts, it
flattens and descends, increasing thoracic volume and creating negative intrathoracic
pressure that draws air into the lungs.
5. The amount of air that can be forcibly exhaled after a normal exhalation is
called:
A. Tidal volume
B. Vital capacity
C. Expiratory reserve volume
D. Residual volume
Correct Answer: C
Rationale: Expiratory reserve volume (ERV) is the additional amount of air
(approximately 1,000-1,200 mL in adults) that can be forcibly exhaled after a normal,
passive exhalation.
6. Which physiological factor has the greatest impact on the oxygen-hemoglobin
dissociation curve shift to the right, facilitating oxygen release to tissues?
A. Decreased body temperature
B. Decreased 2,3-DPG levels
C. Increased PaCO2 and decreased pH
D. Decreased hydrogen ion concentration
Correct Answer: C
Rationale: Increased PaCO2 and decreased pH (Bohr effect) shift the oxyhemoglobin
,dissociation curve to the right, reducing hemoglobin's affinity for oxygen and promoting
oxygen unloading to metabolically active tissues.
7. A patient has a ventilation-perfusion (V/Q) mismatch characterized by adequate
ventilation but inadequate perfusion. This describes:
A. Anatomical shunt
B. Physiological dead space
C. Intrapulmonary shunt
D. Hypercapnia
Correct Answer: B
Rationale: Physiological dead space occurs when alveoli are ventilated but not
perfused (high V/Q ratio), resulting in wasted ventilation that does not participate in gas
exchange, as seen in pulmonary embolism.
8. Which structure prevents food and liquid from entering the trachea during
swallowing?
A. Epiglottis
B. Diaphragm
C. Pleura
D. Bronchiole
Correct Answer: A
Rationale: The epiglottis closes over the laryngeal opening during swallowing,
protecting the airway.
9. What is the primary function of alveoli?
A. Produce mucus
B. Exchange gases
C. Filter inhaled particles
D. Warm inspired air
Correct Answer: B
Rationale: Alveoli are the main sites where oxygen and carbon dioxide are exchanged.
10. A patient with dyspnea should first be placed in which position?
A. Prone
B. Supine
C. High Fowler's
D. Trendelenburg
Correct Answer: C
Rationale: High Fowler's promotes lung expansion and eases breathing.
, 11. Which assessment finding is most consistent with hypoxemia?
A. Bradycardia
B. Cyanosis
C. Polyuria
D. Hyperactive bowel sounds
Correct Answer: B
Rationale: Cyanosis may indicate reduced oxygen saturation in the blood.
12. The nurse is measuring oxygen saturation with a pulse oximeter. What does
this test estimate?
A. Lung compliance
B. Hemoglobin concentration
C. Percent of hemoglobin saturated with oxygen
D. Arterial carbon dioxide level
Correct Answer: C
Rationale: Pulse oximetry estimates oxygen saturation of hemoglobin.
13. A patient suddenly develops unilateral absent breath sounds after a central
line insertion. What is the priority concern?
A. Atelectasis
B. Pneumothorax
C. Pulmonary embolism
D. Pleural effusion
Correct Answer: B
Rationale: Unilateral absent breath sounds after central line insertion is a classic sign
of pneumothorax, a potential complication of the procedure.
14. Which term describes the volume of air remaining in the lungs after a forceful
expiration?
A. Tidal volume
B. Vital capacity
C. Expiratory reserve volume
D. Residual volume
Correct Answer: D
Rationale: Residual volume is the volume of air remaining in the lungs after a forceful
expiration.
15. What is the vital capacity?
A. The volume of air remaining in the lungs after forceful expiration
B. The maximum volume of air that is expired after a maximum inspiration
COMPREHENSIVE EXAM QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A
SECTION 1: RESPIRATORY ANATOMY & PHYSIOLOGY (15 Questions)
1. Which structure creates the greatest portion of the pressure gradient that
drives inspiration?
A. External intercostal muscles
B. Diaphragm
C. Internal intercostal muscles
D. Scalenes
Correct Answer: B
Rationale: Contraction of the diaphragm flattens the dome, increasing thoracic volume
and decreasing intrapleural pressure, which is the primary driver of inspiration.
2. Surfactant primarily affects which of the following lung properties?
A. Elastic recoil
B. Airway resistance
C. Lung compliance
D. Diffusion capacity
Correct Answer: C
Rationale: Surfactant reduces surface tension within alveoli, increasing lung
compliance and making expansion easier. It is required to keep the alveoli from
collapsing and causing atelectasis.
3. Which process refers to the movement of oxygen and carbon dioxide between
the alveoli and the pulmonary capillaries?
,A. Ventilation
B. Diffusion
C. Perfusion
D. Oxygenation
Correct Answer: B
Rationale: Diffusion is the passive movement of gases (oxygen and carbon dioxide)
across the alveolar-capillary membrane down their concentration gradients, driven by
partial pressure differences between the alveoli and blood.
4. A nurse is reviewing the mechanics of breathing. Which muscle is the primary
muscle of inspiration?
A. Internal intercostal muscles
B. Diaphragm
C. Abdominal muscles
D. Sternocleidomastoid
Correct Answer: B
Rationale: The diaphragm is the primary muscle of inspiration; when it contracts, it
flattens and descends, increasing thoracic volume and creating negative intrathoracic
pressure that draws air into the lungs.
5. The amount of air that can be forcibly exhaled after a normal exhalation is
called:
A. Tidal volume
B. Vital capacity
C. Expiratory reserve volume
D. Residual volume
Correct Answer: C
Rationale: Expiratory reserve volume (ERV) is the additional amount of air
(approximately 1,000-1,200 mL in adults) that can be forcibly exhaled after a normal,
passive exhalation.
6. Which physiological factor has the greatest impact on the oxygen-hemoglobin
dissociation curve shift to the right, facilitating oxygen release to tissues?
A. Decreased body temperature
B. Decreased 2,3-DPG levels
C. Increased PaCO2 and decreased pH
D. Decreased hydrogen ion concentration
Correct Answer: C
Rationale: Increased PaCO2 and decreased pH (Bohr effect) shift the oxyhemoglobin
,dissociation curve to the right, reducing hemoglobin's affinity for oxygen and promoting
oxygen unloading to metabolically active tissues.
7. A patient has a ventilation-perfusion (V/Q) mismatch characterized by adequate
ventilation but inadequate perfusion. This describes:
A. Anatomical shunt
B. Physiological dead space
C. Intrapulmonary shunt
D. Hypercapnia
Correct Answer: B
Rationale: Physiological dead space occurs when alveoli are ventilated but not
perfused (high V/Q ratio), resulting in wasted ventilation that does not participate in gas
exchange, as seen in pulmonary embolism.
8. Which structure prevents food and liquid from entering the trachea during
swallowing?
A. Epiglottis
B. Diaphragm
C. Pleura
D. Bronchiole
Correct Answer: A
Rationale: The epiglottis closes over the laryngeal opening during swallowing,
protecting the airway.
9. What is the primary function of alveoli?
A. Produce mucus
B. Exchange gases
C. Filter inhaled particles
D. Warm inspired air
Correct Answer: B
Rationale: Alveoli are the main sites where oxygen and carbon dioxide are exchanged.
10. A patient with dyspnea should first be placed in which position?
A. Prone
B. Supine
C. High Fowler's
D. Trendelenburg
Correct Answer: C
Rationale: High Fowler's promotes lung expansion and eases breathing.
, 11. Which assessment finding is most consistent with hypoxemia?
A. Bradycardia
B. Cyanosis
C. Polyuria
D. Hyperactive bowel sounds
Correct Answer: B
Rationale: Cyanosis may indicate reduced oxygen saturation in the blood.
12. The nurse is measuring oxygen saturation with a pulse oximeter. What does
this test estimate?
A. Lung compliance
B. Hemoglobin concentration
C. Percent of hemoglobin saturated with oxygen
D. Arterial carbon dioxide level
Correct Answer: C
Rationale: Pulse oximetry estimates oxygen saturation of hemoglobin.
13. A patient suddenly develops unilateral absent breath sounds after a central
line insertion. What is the priority concern?
A. Atelectasis
B. Pneumothorax
C. Pulmonary embolism
D. Pleural effusion
Correct Answer: B
Rationale: Unilateral absent breath sounds after central line insertion is a classic sign
of pneumothorax, a potential complication of the procedure.
14. Which term describes the volume of air remaining in the lungs after a forceful
expiration?
A. Tidal volume
B. Vital capacity
C. Expiratory reserve volume
D. Residual volume
Correct Answer: D
Rationale: Residual volume is the volume of air remaining in the lungs after a forceful
expiration.
15. What is the vital capacity?
A. The volume of air remaining in the lungs after forceful expiration
B. The maximum volume of air that is expired after a maximum inspiration
