NU 545 Unit 5 Exam | Questions and
Answers | 2026 Update | 100% Correct -
University of South Alabama.
Question 1
Which alveolar cell type is responsible for surfactant production?
A) Alveolar Type I cells
B) Alveolar Type II cells
C) Alveolar macrophages
D) Clara cells
Correct Answer: B
Rationale: Alveolar Type II cells produce and secrete surfactant, a lipoprotein
mixture that coats the inner surface of the alveolus. Surfactant lowers alveolar
surface tension at end-expiration, preventing alveolar collapse. Type I cells provide
the structure of the alveolar wall, and alveolar macrophages ingest foreign material.
Question 2
What is the primary function of pulmonary surfactant?
,A) To increase alveolar surface tension
B) To decrease alveolar surface tension at end expiration
C) To promote alveolar collapse
D) To increase lung compliance
Correct Answer: B
Rationale: Surfactant lowers alveolar surface tension at end expiration, preventing
alveolar collapse (atelectasis) and promoting alveolar ventilation. It also
contributes to the control of lung inflammation and innate and adaptive immunity.
Question 3
Why are premature infants at high risk for surfactant deficiency disorder?
A) They produce too much surfactant
B) Surfactant secretion does not begin until approximately 20–24 weeks gestation
C) They have too many Type I cells
D) They lack alveolar macrophages
Correct Answer: B
Rationale: Surfactant is produced by 20–24 weeks of gestation and is secreted into
the fetal airways by 30 weeks. Premature infants born before surfactant production
is adequate are at risk for alveolar collapse, impaired gas exchange, hypoxemia,
and atelectasis (neonatal respiratory distress syndrome).
Question 4
What are the four primary steps of oxygen transport in the body?
,A) Ventilation, diffusion, perfusion, and cellular respiration
B) Ventilation of the lungs, diffusion of oxygen from alveoli into capillary blood,
perfusion of systemic capillaries, and diffusion of oxygen into body cells
C) Inspiration, expiration, gas exchange, and circulation
D) Oxygen binding, transport, release, and metabolism
Correct Answer: B
Rationale: The four primary steps are: (1) ventilation of the lungs, (2) diffusion of
oxygen from alveoli into capillary blood, (3) perfusion of systemic capillaries with
oxygenated blood, and (4) diffusion of oxygen from capillaries into body cells.
Question 5
What does a normal ventilation–perfusion (V/Q) ratio equal?
A) 0.5
B) 0.8
C) 1.0
D) 1.5
Correct Answer: B
Rationale: The normal V/Q ratio is approximately 0.8, meaning perfusion slightly
exceeds ventilation under normal conditions.
Question 6
Which areas of the lung are best ventilated and perfused in an upright individual?
, A) The apices
B) The bases
C) The mid-lung regions
D) The hila
Correct Answer: B
Rationale: The bases of the lungs are best ventilated and perfused in an upright
individual due to greater compliance and higher blood pressure.
Question 7
What two forms carry oxygen in the blood?
A) Bound to hemoglobin and dissolved in plasma
B) As bicarbonate and dissolved in plasma
C) Bound to albumin and as free oxygen
D) As oxyhemoglobin and carbaminohemoglobin
Correct Answer: A
Rationale: Oxygen is carried in the blood in two forms: (1) bound to hemoglobin
(approximately 98%) and (2) dissolved in plasma (approximately 2%).
Question 8
What causes a rightward shift of the oxyhemoglobin dissociation curve?
A) Alkalosis and hypothermia
B) Acidosis, hypercapnia, hyperthermia, increased CO₂, increased H⁺, and
Answers | 2026 Update | 100% Correct -
University of South Alabama.
Question 1
Which alveolar cell type is responsible for surfactant production?
A) Alveolar Type I cells
B) Alveolar Type II cells
C) Alveolar macrophages
D) Clara cells
Correct Answer: B
Rationale: Alveolar Type II cells produce and secrete surfactant, a lipoprotein
mixture that coats the inner surface of the alveolus. Surfactant lowers alveolar
surface tension at end-expiration, preventing alveolar collapse. Type I cells provide
the structure of the alveolar wall, and alveolar macrophages ingest foreign material.
Question 2
What is the primary function of pulmonary surfactant?
,A) To increase alveolar surface tension
B) To decrease alveolar surface tension at end expiration
C) To promote alveolar collapse
D) To increase lung compliance
Correct Answer: B
Rationale: Surfactant lowers alveolar surface tension at end expiration, preventing
alveolar collapse (atelectasis) and promoting alveolar ventilation. It also
contributes to the control of lung inflammation and innate and adaptive immunity.
Question 3
Why are premature infants at high risk for surfactant deficiency disorder?
A) They produce too much surfactant
B) Surfactant secretion does not begin until approximately 20–24 weeks gestation
C) They have too many Type I cells
D) They lack alveolar macrophages
Correct Answer: B
Rationale: Surfactant is produced by 20–24 weeks of gestation and is secreted into
the fetal airways by 30 weeks. Premature infants born before surfactant production
is adequate are at risk for alveolar collapse, impaired gas exchange, hypoxemia,
and atelectasis (neonatal respiratory distress syndrome).
Question 4
What are the four primary steps of oxygen transport in the body?
,A) Ventilation, diffusion, perfusion, and cellular respiration
B) Ventilation of the lungs, diffusion of oxygen from alveoli into capillary blood,
perfusion of systemic capillaries, and diffusion of oxygen into body cells
C) Inspiration, expiration, gas exchange, and circulation
D) Oxygen binding, transport, release, and metabolism
Correct Answer: B
Rationale: The four primary steps are: (1) ventilation of the lungs, (2) diffusion of
oxygen from alveoli into capillary blood, (3) perfusion of systemic capillaries with
oxygenated blood, and (4) diffusion of oxygen from capillaries into body cells.
Question 5
What does a normal ventilation–perfusion (V/Q) ratio equal?
A) 0.5
B) 0.8
C) 1.0
D) 1.5
Correct Answer: B
Rationale: The normal V/Q ratio is approximately 0.8, meaning perfusion slightly
exceeds ventilation under normal conditions.
Question 6
Which areas of the lung are best ventilated and perfused in an upright individual?
, A) The apices
B) The bases
C) The mid-lung regions
D) The hila
Correct Answer: B
Rationale: The bases of the lungs are best ventilated and perfused in an upright
individual due to greater compliance and higher blood pressure.
Question 7
What two forms carry oxygen in the blood?
A) Bound to hemoglobin and dissolved in plasma
B) As bicarbonate and dissolved in plasma
C) Bound to albumin and as free oxygen
D) As oxyhemoglobin and carbaminohemoglobin
Correct Answer: A
Rationale: Oxygen is carried in the blood in two forms: (1) bound to hemoglobin
(approximately 98%) and (2) dissolved in plasma (approximately 2%).
Question 8
What causes a rightward shift of the oxyhemoglobin dissociation curve?
A) Alkalosis and hypothermia
B) Acidosis, hypercapnia, hyperthermia, increased CO₂, increased H⁺, and
