Bio 253 Exam 3 Questions & Correct Detailed
Verified Answers Latest Updated 2026 Answers
(GUARANTEED PASS)
QUESTION 1
During the respiratory cycle, intrapleural pressure is always less than
alveolar pressure. This difference is called:
A. Transpulmonary pressure
B. Intrapleural pressure gradient
C. Alveolar pressure difference
D. Respiratory pressure differential
• VERIFIED ANSWER: A. Transpulmonary pressure
• Rationale: Transpulmonary pressure is specifically defined as
the difference between alveolar pressure and intrapleural
pressure. This pressure gradient is essential for keeping the
lungs inflated and preventing collapse. A positive transpulmonary
pressure indicates the lungs are being held open against their
natural tendency to recoil.
QUESTION 2
The sensors that provide feedback information to the medullary
rhythmicity area are the:
,A. Peripheral chemoreceptors only
B. Central chemoreceptors only
C. Both central chemoreceptors and peripheral chemoreceptors
D. Pulmonary stretch receptors only
• VERIFIED ANSWER: C. Both central chemoreceptors and
peripheral chemoreceptors
• Rationale: The medullary respiratory center receives input from
both central chemoreceptors (located in the medulla, sensitive to
changes in CSF H+ concentration reflecting PCO2) and peripheral
chemoreceptors (located in carotid and aortic bodies, sensitive
to changes in arterial PO2, PCO2, and H+). These feedback
mechanisms help regulate breathing to maintain appropriate
blood gas levels.
QUESTION 3
The apparatus used to measure the volume of air exchanged in
breathing is called a(n):
A. Pneumotachometer
B. Spirometer
C. Respirometer
D. Ventilometer
• VERIFIED ANSWER: B. Spirometer
• Rationale: A spirometer is the standard instrument used to
measure the volume of air inspired and expired by the lungs. It
produces a spirogram that records various lung volumes and
, capacities, including tidal volume, vital capacity, and forced
expiratory volume, which are essential for diagnosing respiratory
disorders.
QUESTION 4
The basic rhythm of the respiratory cycle of inspiration and expiration
seems to be generated by the:
A. Pneumotaxic center
B. Apneustic center
C. Medullary rhythmicity area
D. Pontine respiratory group
• VERIFIED ANSWER: C. Medullary rhythmicity area
• Rationale: The medullary rhythmicity area, located in the medulla
oblongata, contains the dorsal respiratory group (DRG) and
ventral respiratory group (VRG) that establish the basic rhythm
of breathing. The pre-Bötzinger complex within this area contains
pacemaker cells that generate the intrinsic respiratory rhythm,
setting the baseline rate and pattern of inspiration and
expiration.
QUESTION 5
Which term refers to the volume of inspired air that actually reaches,
or "ventilates," the alveoli?
, A. Tidal volume
B. Minute ventilation
C. Alveolar ventilation
D. Dead space ventilation
• VERIFIED ANSWER: C. Alveolar ventilation
• Rationale: Alveolar ventilation is the volume of air per minute
that reaches the respiratory zone (alveoli) where gas exchange
occurs. It is calculated as (tidal volume - dead space volume) ×
respiratory rate. This is a more clinically relevant measurement
than minute ventilation because it represents the air actually
participating in gas exchange, excluding air remaining in the
conducting airways (anatomical dead space).
QUESTION 6
The mechanism that produces pulmonary ventilation is one that
establishes a gas pressure gradient between the:
A. Alveoli and the pulmonary capillaries
B. Atmosphere and the alveolar air
C. Intrapleural space and the atmosphere
D. Pulmonary arteries and veins
• VERIFIED ANSWER: B. Atmosphere and the alveolar air
• Rationale: Pulmonary ventilation (breathing) occurs when a
pressure gradient is established between the atmosphere and
the alveoli. During inspiration, alveolar pressure becomes less
than atmospheric pressure, causing air to flow into the lungs.
Verified Answers Latest Updated 2026 Answers
(GUARANTEED PASS)
QUESTION 1
During the respiratory cycle, intrapleural pressure is always less than
alveolar pressure. This difference is called:
A. Transpulmonary pressure
B. Intrapleural pressure gradient
C. Alveolar pressure difference
D. Respiratory pressure differential
• VERIFIED ANSWER: A. Transpulmonary pressure
• Rationale: Transpulmonary pressure is specifically defined as
the difference between alveolar pressure and intrapleural
pressure. This pressure gradient is essential for keeping the
lungs inflated and preventing collapse. A positive transpulmonary
pressure indicates the lungs are being held open against their
natural tendency to recoil.
QUESTION 2
The sensors that provide feedback information to the medullary
rhythmicity area are the:
,A. Peripheral chemoreceptors only
B. Central chemoreceptors only
C. Both central chemoreceptors and peripheral chemoreceptors
D. Pulmonary stretch receptors only
• VERIFIED ANSWER: C. Both central chemoreceptors and
peripheral chemoreceptors
• Rationale: The medullary respiratory center receives input from
both central chemoreceptors (located in the medulla, sensitive to
changes in CSF H+ concentration reflecting PCO2) and peripheral
chemoreceptors (located in carotid and aortic bodies, sensitive
to changes in arterial PO2, PCO2, and H+). These feedback
mechanisms help regulate breathing to maintain appropriate
blood gas levels.
QUESTION 3
The apparatus used to measure the volume of air exchanged in
breathing is called a(n):
A. Pneumotachometer
B. Spirometer
C. Respirometer
D. Ventilometer
• VERIFIED ANSWER: B. Spirometer
• Rationale: A spirometer is the standard instrument used to
measure the volume of air inspired and expired by the lungs. It
produces a spirogram that records various lung volumes and
, capacities, including tidal volume, vital capacity, and forced
expiratory volume, which are essential for diagnosing respiratory
disorders.
QUESTION 4
The basic rhythm of the respiratory cycle of inspiration and expiration
seems to be generated by the:
A. Pneumotaxic center
B. Apneustic center
C. Medullary rhythmicity area
D. Pontine respiratory group
• VERIFIED ANSWER: C. Medullary rhythmicity area
• Rationale: The medullary rhythmicity area, located in the medulla
oblongata, contains the dorsal respiratory group (DRG) and
ventral respiratory group (VRG) that establish the basic rhythm
of breathing. The pre-Bötzinger complex within this area contains
pacemaker cells that generate the intrinsic respiratory rhythm,
setting the baseline rate and pattern of inspiration and
expiration.
QUESTION 5
Which term refers to the volume of inspired air that actually reaches,
or "ventilates," the alveoli?
, A. Tidal volume
B. Minute ventilation
C. Alveolar ventilation
D. Dead space ventilation
• VERIFIED ANSWER: C. Alveolar ventilation
• Rationale: Alveolar ventilation is the volume of air per minute
that reaches the respiratory zone (alveoli) where gas exchange
occurs. It is calculated as (tidal volume - dead space volume) ×
respiratory rate. This is a more clinically relevant measurement
than minute ventilation because it represents the air actually
participating in gas exchange, excluding air remaining in the
conducting airways (anatomical dead space).
QUESTION 6
The mechanism that produces pulmonary ventilation is one that
establishes a gas pressure gradient between the:
A. Alveoli and the pulmonary capillaries
B. Atmosphere and the alveolar air
C. Intrapleural space and the atmosphere
D. Pulmonary arteries and veins
• VERIFIED ANSWER: B. Atmosphere and the alveolar air
• Rationale: Pulmonary ventilation (breathing) occurs when a
pressure gradient is established between the atmosphere and
the alveoli. During inspiration, alveolar pressure becomes less
than atmospheric pressure, causing air to flow into the lungs.
