1
BIOS 255 / BIOS255 Anatomy and Physiology III with
Lab Exam 2 Actual Exam 2026/2027 – Complete
Exam-Style Questions with Detailed Rationales | 100%
Verified – Pass Guaranteed – A+ Graded
Section 1: Respiratory System - Anatomy & Ventilation (Questions 1-18)
Q1: Which anatomical structure contains C-shaped cartilage rings that prevent collapse during
inspiration but allow the esophagus to expand during swallowing?
A. Bronchi
B. Trachea
C. Larynx
D. Pharynx
C. B. Trachea [CORRECT]
Correct Answer: B
Rationale: The trachea contains 16-20 C-shaped rings of hyaline cartilage. The open posterior
part of the "C" faces the esophagus, allowing it to expand when food is swallowed.
Q2: The bronchial tree divides from the primary bronchi into secondary and tertiary bronchi,
eventually terminating in the:
A. Alveolar ducts
B. Respiratory bronchioles
C. Terminal bronchioles
D. Alveolar sacs
C. C. Terminal bronchioles [CORRECT]
Correct Answer: C
Rationale: The conducting zone ends at the terminal bronchioles. Beyond this point (respiratory
bronchioles, alveolar ducts, and alveoli), gas exchange occurs.
,2
Q3: Which cell type in the alveoli is responsible for secreting surfactant to reduce surface
tension?
A. Type I pneumocytes
B. Type II pneumocytes
C. Alveolar macrophages
D. Goblet cells
C. B. Type II pneumocytes [CORRECT]
Correct Answer: B
Rationale: Type II pneumocytes are cuboidal cells that secrete surfactant, a lipoprotein mixture
(containing DPPC) that lowers surface tension and prevents alveolar collapse (atelectasis).
Q4: A premature infant is born with Infant Respiratory Distress Syndrome (IRDS). The primary
pathophysiology of this condition is:
A. Underdeveloped diaphragm muscles.
B. Lack of surfactant leading to increased alveolar surface tension and collapse.
C. Pulmonary hypertension.
D. Congenital heart defect.
C. B. Lack of surfactant leading to increased alveolar surface tension and collapse. [CORRECT]
Correct Answer: B
Rationale: IRDS occurs primarily in premature infants whose Type II pneumocytes have not
produced enough surfactant. Without surfactant, the high surface tension causes alveoli to
collapse, making inflation difficult.
Q5: During inhalation, the diaphragm contracts and moves:
A. Upward, decreasing thoracic volume.
B. Upward, increasing thoracic volume.
C. Downward, decreasing thoracic volume.
D. Downward, increasing thoracic volume.
C. D. Downward, increasing thoracic volume. [CORRECT]
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Correct Answer: D
Rationale: Contraction of the diaphragm causes it to flatten and move inferiorly. This increases
the vertical dimension of the thorax, decreasing intrapulmonary pressure and allowing air to flow
in (Boyle's Law).
Q6: The intrapleural pressure is normally:
A. Equal to atmospheric pressure.
B. Higher than atmospheric pressure.
C. Subatmospheric (negative).
D. Zero.
C. C. Subatmospheric (negative). [CORRECT]
Correct Answer: C
Rationale: Intrapleural pressure is always negative (approx. -4 mmHg at rest) due to the
opposing elastic recoil of the lungs (inward) and chest wall (outward). This negative pressure
keeps the lungs inflated.
Q7: A patient suffers a penetrating chest wound (pneumothorax). What is the immediate effect on
the affected lung?
A. The lung over-inflates.
B. The lung collapses due to equalization of intrapleural and atmospheric pressure.
C. The diaphragm contracts more forcefully.
D. Surfactant production stops.
C. B. The lung collapses due to equalization of intrapleural and atmospheric pressure.
[CORRECT]
Correct Answer: B
Rationale: A pneumothorax allows air to enter the pleural space, destroying the negative
intrapleural pressure. Without the negative pressure holding the lung open against the chest wall,
the lung collapses due to its own elastic recoil.
Q8: Which of the following describes lung compliance?
BIOS 255 / BIOS255 Anatomy and Physiology III with
Lab Exam 2 Actual Exam 2026/2027 – Complete
Exam-Style Questions with Detailed Rationales | 100%
Verified – Pass Guaranteed – A+ Graded
Section 1: Respiratory System - Anatomy & Ventilation (Questions 1-18)
Q1: Which anatomical structure contains C-shaped cartilage rings that prevent collapse during
inspiration but allow the esophagus to expand during swallowing?
A. Bronchi
B. Trachea
C. Larynx
D. Pharynx
C. B. Trachea [CORRECT]
Correct Answer: B
Rationale: The trachea contains 16-20 C-shaped rings of hyaline cartilage. The open posterior
part of the "C" faces the esophagus, allowing it to expand when food is swallowed.
Q2: The bronchial tree divides from the primary bronchi into secondary and tertiary bronchi,
eventually terminating in the:
A. Alveolar ducts
B. Respiratory bronchioles
C. Terminal bronchioles
D. Alveolar sacs
C. C. Terminal bronchioles [CORRECT]
Correct Answer: C
Rationale: The conducting zone ends at the terminal bronchioles. Beyond this point (respiratory
bronchioles, alveolar ducts, and alveoli), gas exchange occurs.
,2
Q3: Which cell type in the alveoli is responsible for secreting surfactant to reduce surface
tension?
A. Type I pneumocytes
B. Type II pneumocytes
C. Alveolar macrophages
D. Goblet cells
C. B. Type II pneumocytes [CORRECT]
Correct Answer: B
Rationale: Type II pneumocytes are cuboidal cells that secrete surfactant, a lipoprotein mixture
(containing DPPC) that lowers surface tension and prevents alveolar collapse (atelectasis).
Q4: A premature infant is born with Infant Respiratory Distress Syndrome (IRDS). The primary
pathophysiology of this condition is:
A. Underdeveloped diaphragm muscles.
B. Lack of surfactant leading to increased alveolar surface tension and collapse.
C. Pulmonary hypertension.
D. Congenital heart defect.
C. B. Lack of surfactant leading to increased alveolar surface tension and collapse. [CORRECT]
Correct Answer: B
Rationale: IRDS occurs primarily in premature infants whose Type II pneumocytes have not
produced enough surfactant. Without surfactant, the high surface tension causes alveoli to
collapse, making inflation difficult.
Q5: During inhalation, the diaphragm contracts and moves:
A. Upward, decreasing thoracic volume.
B. Upward, increasing thoracic volume.
C. Downward, decreasing thoracic volume.
D. Downward, increasing thoracic volume.
C. D. Downward, increasing thoracic volume. [CORRECT]
, 3
Correct Answer: D
Rationale: Contraction of the diaphragm causes it to flatten and move inferiorly. This increases
the vertical dimension of the thorax, decreasing intrapulmonary pressure and allowing air to flow
in (Boyle's Law).
Q6: The intrapleural pressure is normally:
A. Equal to atmospheric pressure.
B. Higher than atmospheric pressure.
C. Subatmospheric (negative).
D. Zero.
C. C. Subatmospheric (negative). [CORRECT]
Correct Answer: C
Rationale: Intrapleural pressure is always negative (approx. -4 mmHg at rest) due to the
opposing elastic recoil of the lungs (inward) and chest wall (outward). This negative pressure
keeps the lungs inflated.
Q7: A patient suffers a penetrating chest wound (pneumothorax). What is the immediate effect on
the affected lung?
A. The lung over-inflates.
B. The lung collapses due to equalization of intrapleural and atmospheric pressure.
C. The diaphragm contracts more forcefully.
D. Surfactant production stops.
C. B. The lung collapses due to equalization of intrapleural and atmospheric pressure.
[CORRECT]
Correct Answer: B
Rationale: A pneumothorax allows air to enter the pleural space, destroying the negative
intrapleural pressure. Without the negative pressure holding the lung open against the chest wall,
the lung collapses due to its own elastic recoil.
Q8: Which of the following describes lung compliance?
