BIOL 235 MIDTERM 2
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The upper respiratory tract differs from the lower respiratory tract in what way?
a. Air is taken in through the lower respiratory tract, and CO2/O2 are exchanged
in the upper respiratory tract
b. Air is taken in through the upper respiratory tract, and CO2/O2 are exchanged
in the lower respiratory tract
c. CO2 is removed from circulation in the upper respiratory tract
d. O2 is removed from circulation in the lower respiratory tract
✔️ Correct Answer: B
Rationale: Air is taken in through the upper respiratory tract (nose, pharynx,
larynx), and gas exchange (CO2/O2) occurs in the lower respiratory tract (trachea,
bronchi, bronchioles, alveoli). Option A reverses these functions. Options C and D
are incorrect descriptions of gas exchange.
,Smooth muscle surrounds which structure of the lower respiratory tract?
a. Alveoli
b. Alveolar capillaries
c. Terminal bronchioles
d. Trachea
✔️ Correct Answer: C
Rationale: Terminal bronchioles are surrounded by smooth muscle that can
constrict or dilate to regulate airflow. Alveoli (Option A) are composed of
epithelial cells. Alveolar capillaries (Option B) are not surrounded by smooth
muscle. The trachea (Option D) contains cartilaginous rings, not smooth muscle.
In the alveolus, ____ squamous epithelial cells are responsible for ____, while ____
cells are responsible for ____.
a. Type 1; surfactant secretion; Type 2; gas exchange
b. Type 1; debris removal; Type 2; surfactant secretion
c. Type 3; debris removal; Type 1; gas exchange
d. Type 1; gas exchange; Type 2; surfactant secretion
✔️ Correct Answer: D
Rationale: Type 1 alveolar cells are thin squamous epithelial cells responsible for
gas exchange. Type 2 alveolar cells are responsible for surfactant secretion, which
reduces surface tension. Type 3 cells do not exist in alveolar epithelium. Surfactant
secretion is not a function of Type 1 cells, and gas exchange is not a function of
Type 2 cells.
,There is no net air flow into or out of the lungs when:
a. P alveolus = P atmosphere
b. P alveolus < P atmosphere
c. P pleural wall > P atmosphere
d. P atmosphere < P pleural wall
✔️ Correct Answer: A
Rationale: When alveolar pressure equals atmospheric pressure, there is no
pressure gradient, so no net airflow occurs. Option B would result in air flowing
into the lungs. Options C and D are incorrect because pleural pressure is not
directly compared to atmospheric pressure in this context.
What keeps the lungs from collapsing?
a. Transpulmonary negative pressure caused by negative pressure from the
pleural cavity
b. Positive pressure from the pleural cavity
c. Surfactant alone
d. Elastic recoil of the lungs
✔️ Correct Answer: A
Rationale: Transpulmonary pressure (the difference between alveolar pressure
and pleural pressure) is maintained as a negative pressure by the pleural cavity,
keeping the lungs inflated. Surfactant (Option C) reduces surface tension but does
not alone keep lungs from collapsing. Elastic recoil (Option D) would collapse
lungs without opposing forces.
, Identify the correct sequence of events for inspiration:
a. Diaphragm and inspiratory intercostals relax, lungs expand, air flows into alveoli
b. Diaphragm and inspiratory intercostals contract, lungs expand, air flows out of
the alveoli
c. Diaphragm and inspiratory intercostals contract, lungs expand, air flows into
alveoli
d. Diaphragm and expiratory intercostals relax, lungs contract, air flows out of
alveoli
✔️ Correct Answer: C
Rationale: During inspiration, the diaphragm and inspiratory intercostals contract,
which expands the lungs, decreasing alveolar pressure, and air flows into the
alveoli. Option A describes expiration. Option B incorrectly states air flows out.
Option D describes expiration.
The main determinants of lung compliance are:
a. Lung tissue thickness, surface tension of fluid on the inner lung surface
b. Lung tissue perforations, surface tension of fluid on the inner lung surface
c. Lung tissue surface area, surface tension of fluid on the inner lung surface
d. Lung tissue thickness, surface tension of fluid on the outer lung surface
✔️ Correct Answer: A
Rationale: Lung compliance is determined by lung tissue thickness and the
surface tension of fluid on the inner lung surface (alveolar surface tension).
Perforations (Option B) are pathological. Surface area (Option C) relates to gas
ALL Questions and Answers Biology
100% verified | LATEST 2026 UPDATED
VERSION
2026/2027 Frequently Most Tested Questions and
100% Accurate From Past papers | Graded A+ ,
Reviewed and Updated | 100% Guarantee Pass |
Latest Exam and Newest Version!!!
The upper respiratory tract differs from the lower respiratory tract in what way?
a. Air is taken in through the lower respiratory tract, and CO2/O2 are exchanged
in the upper respiratory tract
b. Air is taken in through the upper respiratory tract, and CO2/O2 are exchanged
in the lower respiratory tract
c. CO2 is removed from circulation in the upper respiratory tract
d. O2 is removed from circulation in the lower respiratory tract
✔️ Correct Answer: B
Rationale: Air is taken in through the upper respiratory tract (nose, pharynx,
larynx), and gas exchange (CO2/O2) occurs in the lower respiratory tract (trachea,
bronchi, bronchioles, alveoli). Option A reverses these functions. Options C and D
are incorrect descriptions of gas exchange.
,Smooth muscle surrounds which structure of the lower respiratory tract?
a. Alveoli
b. Alveolar capillaries
c. Terminal bronchioles
d. Trachea
✔️ Correct Answer: C
Rationale: Terminal bronchioles are surrounded by smooth muscle that can
constrict or dilate to regulate airflow. Alveoli (Option A) are composed of
epithelial cells. Alveolar capillaries (Option B) are not surrounded by smooth
muscle. The trachea (Option D) contains cartilaginous rings, not smooth muscle.
In the alveolus, ____ squamous epithelial cells are responsible for ____, while ____
cells are responsible for ____.
a. Type 1; surfactant secretion; Type 2; gas exchange
b. Type 1; debris removal; Type 2; surfactant secretion
c. Type 3; debris removal; Type 1; gas exchange
d. Type 1; gas exchange; Type 2; surfactant secretion
✔️ Correct Answer: D
Rationale: Type 1 alveolar cells are thin squamous epithelial cells responsible for
gas exchange. Type 2 alveolar cells are responsible for surfactant secretion, which
reduces surface tension. Type 3 cells do not exist in alveolar epithelium. Surfactant
secretion is not a function of Type 1 cells, and gas exchange is not a function of
Type 2 cells.
,There is no net air flow into or out of the lungs when:
a. P alveolus = P atmosphere
b. P alveolus < P atmosphere
c. P pleural wall > P atmosphere
d. P atmosphere < P pleural wall
✔️ Correct Answer: A
Rationale: When alveolar pressure equals atmospheric pressure, there is no
pressure gradient, so no net airflow occurs. Option B would result in air flowing
into the lungs. Options C and D are incorrect because pleural pressure is not
directly compared to atmospheric pressure in this context.
What keeps the lungs from collapsing?
a. Transpulmonary negative pressure caused by negative pressure from the
pleural cavity
b. Positive pressure from the pleural cavity
c. Surfactant alone
d. Elastic recoil of the lungs
✔️ Correct Answer: A
Rationale: Transpulmonary pressure (the difference between alveolar pressure
and pleural pressure) is maintained as a negative pressure by the pleural cavity,
keeping the lungs inflated. Surfactant (Option C) reduces surface tension but does
not alone keep lungs from collapsing. Elastic recoil (Option D) would collapse
lungs without opposing forces.
, Identify the correct sequence of events for inspiration:
a. Diaphragm and inspiratory intercostals relax, lungs expand, air flows into alveoli
b. Diaphragm and inspiratory intercostals contract, lungs expand, air flows out of
the alveoli
c. Diaphragm and inspiratory intercostals contract, lungs expand, air flows into
alveoli
d. Diaphragm and expiratory intercostals relax, lungs contract, air flows out of
alveoli
✔️ Correct Answer: C
Rationale: During inspiration, the diaphragm and inspiratory intercostals contract,
which expands the lungs, decreasing alveolar pressure, and air flows into the
alveoli. Option A describes expiration. Option B incorrectly states air flows out.
Option D describes expiration.
The main determinants of lung compliance are:
a. Lung tissue thickness, surface tension of fluid on the inner lung surface
b. Lung tissue perforations, surface tension of fluid on the inner lung surface
c. Lung tissue surface area, surface tension of fluid on the inner lung surface
d. Lung tissue thickness, surface tension of fluid on the outer lung surface
✔️ Correct Answer: A
Rationale: Lung compliance is determined by lung tissue thickness and the
surface tension of fluid on the inner lung surface (alveolar surface tension).
Perforations (Option B) are pathological. Surface area (Option C) relates to gas
