BIOS 255 Exam 3 Questions and Answers with Rationales |
CHAMBERLAIN UNIVERSITY
Question 1. Which function is the best match for pulmonary gas diffusion?
A. carries most carbon dioxide in blood after conversion to bicarbonate
B. increases ventilation when arterial oxygen falls substantially and also responds to CO2 and pH
C. adjusts ventilation mainly in response to changes in brain extracellular fluid pH caused by arterial carbon dioxide
D. moves oxygen and carbon dioxide across the respiratory membrane down their partial-pressure gradients
Correct Answer: D. moves oxygen and carbon dioxide across the respiratory membrane down their
partial-pressure gradients
Explanation: The correct choice describes this function: moves oxygen and carbon dioxide across the respiratory
membrane down their partial-pressure gradients. This is the primary role associated with pulmonary gas diffusion, and it
is supported by the mechanism that molecules move passively from higher to lower partial pressure across the thin
alveolar-capillary barrier. The other choices describe functions performed by different components within the same
course domain.
Question 2. When reviewing normal anatomy and physiology, which feature belongs to epiglottis?
A. it is a small airway with smooth muscle but little to no cartilage
B. it is an elastic cartilage flap at the entrance to the larynx
C. it is a cartilaginous structure between the pharynx and trachea
D. it is divided into nasopharynx, oropharynx, and laryngopharynx
Correct Answer: B. it is an elastic cartilage flap at the entrance to the larynx
Explanation: The identifying feature is that it is an elastic cartilage flap at the entrance to the larynx. That characteristic
is consistent with epiglottis and its normal role: helps protect the lower airway by covering the laryngeal inlet during
swallowing. The other findings are characteristic of different items and do not identify epiglottis as precisely.
Question 3. A major loss of the physiology represented by alveolar ventilation would most likely produce
which consequence?
A. total ventilation would fall if either rate or tidal volume decreased without compensation
B. minute ventilation would fall if tidal volume decreased while respiratory rate stayed constant
C. effective gas exchange would fall during very shallow breathing even if total minute ventilation were unchanged
D. alveolar gas would be completely emptied between maximal breaths if residual volume were zero
Correct Answer: C. effective gas exchange would fall during very shallow breathing even if total minute
ventilation were unchanged
Explanation: The most direct consequence is that effective gas exchange would fall during very shallow breathing even
if total minute ventilation were unchanged. That prediction follows because alveolar ventilation normally has this role:
estimates the volume of fresh air reaching gas-exchange regions each minute. The distractors reflect dysfunction of other
structures or processes rather than the most direct consequence here.
,Question 4. A student creates a two-column study card for active immunity. Which feature/effect pair is
correct?
A. Feature: it is an immunoglobulin molecule with variable antigen-binding regions / Dysfunction: long-lasting
antigen-specific memory would not develop if only preformed antibodies were supplied.
B. Feature: it occurs naturally through maternal antibody transfer or artificially through antibody administration /
Dysfunction: long-lasting antigen-specific memory would not develop if only preformed antibodies were supplied.
C. Feature: it can follow infection or vaccination and usually takes time to develop / Dysfunction: long-lasting
antigen-specific memory would not develop if only preformed antibodies were supplied.
D. Feature: it is a monomer that can cross the placenta / Dysfunction: long-lasting antigen-specific memory would
not develop if only preformed antibodies were supplied.
Correct Answer: C. Feature: it can follow infection or vaccination and usually takes time to develop /
Dysfunction: long-lasting antigen-specific memory would not develop if only preformed antibodies were supplied.
Explanation: For active immunity, the identifying feature is that it can follow infection or vaccination and usually takes
time to develop, and severe dysfunction would mean that long-lasting antigen-specific memory would not develop if
only preformed antibodies were supplied. Both halves of the pairing must be correct for the option to be valid. The
distractors combine the correct consequence with a defining feature that belongs to another item.
Question 5. Severe dysfunction involving inspiratory reserve volume would be expected to cause which
outcome first?
A. total ventilation would fall if either rate or tidal volume decreased without compensation
B. maximal inspiratory capacity would fall if this reserve were reduced
C. alveolar gas would be completely emptied between maximal breaths if residual volume were zero
D. effective gas exchange would fall during very shallow breathing even if total minute ventilation were unchanged
Correct Answer: B. maximal inspiratory capacity would fall if this reserve were reduced
Explanation: The most direct consequence is that maximal inspiratory capacity would fall if this reserve were reduced.
That prediction follows because inspiratory reserve volume normally has this role: is the additional volume that can be
inhaled after a normal tidal inspiration. The distractors reflect dysfunction of other structures or processes rather than the
most direct consequence here.
Question 6. Consider this case: A CD8 lymphocyte recognizes a viral peptide on an infected host cell and
induces apoptosis. What is the best physiologic explanation?
A. the effector cell is a cytotoxic T cell
B. the coordinating lymphocyte is a helper T cell
C. the viral peptide is displayed by MHC class I
D. the recognized molecular region is an antigenic epitope
Correct Answer: A. the effector cell is a cytotoxic T cell
Explanation: The best interpretation is that the effector cell is a cytotoxic T cell. This scenario centers on cytotoxic T
cell, whose normal physiologic role is described as follows: kills infected or abnormal host cells that display relevant
antigen with MHC class I. That relationship is more directly supported by the stated findings than the alternative
explanations.
,Question 7. Which two-part description of conducting zone is physiologically accurate?
A. It moves, filters, warms, and humidifies air but does not perform substantial gas exchange; this is enabled
because swallowing elevates the larynx and positions the epiglottis to help direct material away from the airway.
B. It moves, filters, warms, and humidifies air but does not perform substantial gas exchange; this is enabled
because cartilage resists collapse while cilia move mucus toward the pharynx.
C. It moves, filters, warms, and humidifies air but does not perform substantial gas exchange; this is enabled
because turbulent flow increases contact between inspired air and vascular mucosa.
D. It moves, filters, warms, and humidifies air but does not perform substantial gas exchange; this is enabled
because airways transport air while mucosa and supportive structures condition it before the respiratory zone.
Correct Answer: D. It moves, filters, warms, and humidifies air but does not perform substantial gas exchange;
this is enabled because airways transport air while mucosa and supportive structures condition it before the
respiratory zone.
Explanation: The correct pairing links conducting zone to this role: moves, filters, warms, and humidifies air but does
not perform substantial gas exchange, and to this mechanism: airways transport air while mucosa and supportive
structures condition it before the respiratory zone. A correct function paired with the wrong mechanism is still an
incorrect description. The other options deliberately mix the role of conducting zone with mechanisms that belong to
different components.
Question 8. Which item matches this identifying characteristic: it normally occurs without active
contraction of expiratory muscles?
A. negative intrapleural pressure
B. Boyle law in ventilation
C. lung compliance
D. quiet expiration
Correct Answer: D. quiet expiration
Explanation: The description identifies quiet expiration because it normally occurs without active contraction of
expiratory muscles. Its key role is that it moves air out of the lungs primarily through passive elastic recoil at rest. The
alternative options have different defining features and would not best fit the description.
Question 9. A patient is early in a first exposure to a pathogen and has a rapid rise in pentameric
antibody. Which explanation best accounts for this finding?
A. IgG is the major immunoglobulin class that crosses the placenta
B. the antibody is IgM
C. antibody neutralization blocks the toxin from interacting with its target
D. secretory IgA is a major antibody of mucosal secretions
Correct Answer: B. the antibody is IgM
Explanation: The best interpretation is that the antibody is IgM. This scenario centers on IgM, whose normal physiologic
role is described as follows: is often the first antibody isotype secreted in a primary humoral response and is efficient at
agglutination and complement activation. That relationship is more directly supported by the stated findings than the
alternative explanations.
, Question 10. Which statement correctly connects pulmonary surfactant to what it does and how it
works?
A. It reduces alveolar surface tension and helps stabilize alveoli, especially at low lung volumes; this is enabled
because a thin film of pleural fluid couples it to the parietal pleura while reducing friction.
B. It reduces alveolar surface tension and helps stabilize alveoli, especially at low lung volumes; this is enabled
because contraction flattens the dome, enlarges the thoracic cavity, and lowers alveolar pressure.
C. It reduces alveolar surface tension and helps stabilize alveoli, especially at low lung volumes; this is enabled
because molecules disrupt cohesive forces between water molecules, lowering the pressure required to keep small
alveoli open.
D. It reduces alveolar surface tension and helps stabilize alveoli, especially at low lung volumes; this is enabled
because its lobar organization accommodates branching bronchi and regional pulmonary tissue.
Correct Answer: C. It reduces alveolar surface tension and helps stabilize alveoli, especially at low lung volumes;
this is enabled because molecules disrupt cohesive forces between water molecules, lowering the pressure
required to keep small alveoli open.
Explanation: The correct pairing links pulmonary surfactant to this role: reduces alveolar surface tension and helps
stabilize alveoli, especially at low lung volumes, and to this mechanism: molecules disrupt cohesive forces between
water molecules, lowering the pressure required to keep small alveoli open. A correct function paired with the wrong
mechanism is still an incorrect description. The other options deliberately mix the role of pulmonary surfactant with
mechanisms that belong to different components.
Question 11. Which feature is most characteristic of interferon response?
A. it acts before microbes gain access to internal tissues
B. it is a cascade of plasma proteins that can be activated by several pathways
C. it is performed prominently by neutrophils and macrophages
D. virus-infected cells can release type I interferons early in infection
Correct Answer: D. virus-infected cells can release type I interferons early in infection
Explanation: The identifying feature is that virus-infected cells can release type I interferons early in infection. That
characteristic is consistent with interferon response and its normal role: helps neighboring cells resist viral replication
and coordinates antiviral defenses. The other findings are characteristic of different items and do not identify interferon
response as precisely.
Question 12. Which mechanism best explains the normal physiology of respiratory zone?
A. phagocytosis removes debris that escapes upper-airway filtration and mucociliary clearance
B. large total surface area and minimal diffusion distance support rapid gas transfer
C. very thin exchange surfaces are closely associated with pulmonary capillaries
D. its flattened shape minimizes diffusion distance between alveolar air and capillary blood
Correct Answer: C. very thin exchange surfaces are closely associated with pulmonary capillaries
Explanation: The correct mechanism is that very thin exchange surfaces are closely associated with pulmonary
capillaries. It explains the normal function of respiratory zone: contains the structures where pulmonary gas exchange
occurs. The other mechanisms belong to different structures or processes in the same broad system.
Question 13. Which structure or process is best identified by this description: it is influenced by surface
area, membrane thickness, diffusion coefficient, and partial-pressure difference?
A. carbon monoxide toxicity
B. pulmonary gas diffusion
C. peripheral chemoreceptor response
D. bicarbonate transport of carbon dioxide
Correct Answer: B. pulmonary gas diffusion
CHAMBERLAIN UNIVERSITY
Question 1. Which function is the best match for pulmonary gas diffusion?
A. carries most carbon dioxide in blood after conversion to bicarbonate
B. increases ventilation when arterial oxygen falls substantially and also responds to CO2 and pH
C. adjusts ventilation mainly in response to changes in brain extracellular fluid pH caused by arterial carbon dioxide
D. moves oxygen and carbon dioxide across the respiratory membrane down their partial-pressure gradients
Correct Answer: D. moves oxygen and carbon dioxide across the respiratory membrane down their
partial-pressure gradients
Explanation: The correct choice describes this function: moves oxygen and carbon dioxide across the respiratory
membrane down their partial-pressure gradients. This is the primary role associated with pulmonary gas diffusion, and it
is supported by the mechanism that molecules move passively from higher to lower partial pressure across the thin
alveolar-capillary barrier. The other choices describe functions performed by different components within the same
course domain.
Question 2. When reviewing normal anatomy and physiology, which feature belongs to epiglottis?
A. it is a small airway with smooth muscle but little to no cartilage
B. it is an elastic cartilage flap at the entrance to the larynx
C. it is a cartilaginous structure between the pharynx and trachea
D. it is divided into nasopharynx, oropharynx, and laryngopharynx
Correct Answer: B. it is an elastic cartilage flap at the entrance to the larynx
Explanation: The identifying feature is that it is an elastic cartilage flap at the entrance to the larynx. That characteristic
is consistent with epiglottis and its normal role: helps protect the lower airway by covering the laryngeal inlet during
swallowing. The other findings are characteristic of different items and do not identify epiglottis as precisely.
Question 3. A major loss of the physiology represented by alveolar ventilation would most likely produce
which consequence?
A. total ventilation would fall if either rate or tidal volume decreased without compensation
B. minute ventilation would fall if tidal volume decreased while respiratory rate stayed constant
C. effective gas exchange would fall during very shallow breathing even if total minute ventilation were unchanged
D. alveolar gas would be completely emptied between maximal breaths if residual volume were zero
Correct Answer: C. effective gas exchange would fall during very shallow breathing even if total minute
ventilation were unchanged
Explanation: The most direct consequence is that effective gas exchange would fall during very shallow breathing even
if total minute ventilation were unchanged. That prediction follows because alveolar ventilation normally has this role:
estimates the volume of fresh air reaching gas-exchange regions each minute. The distractors reflect dysfunction of other
structures or processes rather than the most direct consequence here.
,Question 4. A student creates a two-column study card for active immunity. Which feature/effect pair is
correct?
A. Feature: it is an immunoglobulin molecule with variable antigen-binding regions / Dysfunction: long-lasting
antigen-specific memory would not develop if only preformed antibodies were supplied.
B. Feature: it occurs naturally through maternal antibody transfer or artificially through antibody administration /
Dysfunction: long-lasting antigen-specific memory would not develop if only preformed antibodies were supplied.
C. Feature: it can follow infection or vaccination and usually takes time to develop / Dysfunction: long-lasting
antigen-specific memory would not develop if only preformed antibodies were supplied.
D. Feature: it is a monomer that can cross the placenta / Dysfunction: long-lasting antigen-specific memory would
not develop if only preformed antibodies were supplied.
Correct Answer: C. Feature: it can follow infection or vaccination and usually takes time to develop /
Dysfunction: long-lasting antigen-specific memory would not develop if only preformed antibodies were supplied.
Explanation: For active immunity, the identifying feature is that it can follow infection or vaccination and usually takes
time to develop, and severe dysfunction would mean that long-lasting antigen-specific memory would not develop if
only preformed antibodies were supplied. Both halves of the pairing must be correct for the option to be valid. The
distractors combine the correct consequence with a defining feature that belongs to another item.
Question 5. Severe dysfunction involving inspiratory reserve volume would be expected to cause which
outcome first?
A. total ventilation would fall if either rate or tidal volume decreased without compensation
B. maximal inspiratory capacity would fall if this reserve were reduced
C. alveolar gas would be completely emptied between maximal breaths if residual volume were zero
D. effective gas exchange would fall during very shallow breathing even if total minute ventilation were unchanged
Correct Answer: B. maximal inspiratory capacity would fall if this reserve were reduced
Explanation: The most direct consequence is that maximal inspiratory capacity would fall if this reserve were reduced.
That prediction follows because inspiratory reserve volume normally has this role: is the additional volume that can be
inhaled after a normal tidal inspiration. The distractors reflect dysfunction of other structures or processes rather than the
most direct consequence here.
Question 6. Consider this case: A CD8 lymphocyte recognizes a viral peptide on an infected host cell and
induces apoptosis. What is the best physiologic explanation?
A. the effector cell is a cytotoxic T cell
B. the coordinating lymphocyte is a helper T cell
C. the viral peptide is displayed by MHC class I
D. the recognized molecular region is an antigenic epitope
Correct Answer: A. the effector cell is a cytotoxic T cell
Explanation: The best interpretation is that the effector cell is a cytotoxic T cell. This scenario centers on cytotoxic T
cell, whose normal physiologic role is described as follows: kills infected or abnormal host cells that display relevant
antigen with MHC class I. That relationship is more directly supported by the stated findings than the alternative
explanations.
,Question 7. Which two-part description of conducting zone is physiologically accurate?
A. It moves, filters, warms, and humidifies air but does not perform substantial gas exchange; this is enabled
because swallowing elevates the larynx and positions the epiglottis to help direct material away from the airway.
B. It moves, filters, warms, and humidifies air but does not perform substantial gas exchange; this is enabled
because cartilage resists collapse while cilia move mucus toward the pharynx.
C. It moves, filters, warms, and humidifies air but does not perform substantial gas exchange; this is enabled
because turbulent flow increases contact between inspired air and vascular mucosa.
D. It moves, filters, warms, and humidifies air but does not perform substantial gas exchange; this is enabled
because airways transport air while mucosa and supportive structures condition it before the respiratory zone.
Correct Answer: D. It moves, filters, warms, and humidifies air but does not perform substantial gas exchange;
this is enabled because airways transport air while mucosa and supportive structures condition it before the
respiratory zone.
Explanation: The correct pairing links conducting zone to this role: moves, filters, warms, and humidifies air but does
not perform substantial gas exchange, and to this mechanism: airways transport air while mucosa and supportive
structures condition it before the respiratory zone. A correct function paired with the wrong mechanism is still an
incorrect description. The other options deliberately mix the role of conducting zone with mechanisms that belong to
different components.
Question 8. Which item matches this identifying characteristic: it normally occurs without active
contraction of expiratory muscles?
A. negative intrapleural pressure
B. Boyle law in ventilation
C. lung compliance
D. quiet expiration
Correct Answer: D. quiet expiration
Explanation: The description identifies quiet expiration because it normally occurs without active contraction of
expiratory muscles. Its key role is that it moves air out of the lungs primarily through passive elastic recoil at rest. The
alternative options have different defining features and would not best fit the description.
Question 9. A patient is early in a first exposure to a pathogen and has a rapid rise in pentameric
antibody. Which explanation best accounts for this finding?
A. IgG is the major immunoglobulin class that crosses the placenta
B. the antibody is IgM
C. antibody neutralization blocks the toxin from interacting with its target
D. secretory IgA is a major antibody of mucosal secretions
Correct Answer: B. the antibody is IgM
Explanation: The best interpretation is that the antibody is IgM. This scenario centers on IgM, whose normal physiologic
role is described as follows: is often the first antibody isotype secreted in a primary humoral response and is efficient at
agglutination and complement activation. That relationship is more directly supported by the stated findings than the
alternative explanations.
, Question 10. Which statement correctly connects pulmonary surfactant to what it does and how it
works?
A. It reduces alveolar surface tension and helps stabilize alveoli, especially at low lung volumes; this is enabled
because a thin film of pleural fluid couples it to the parietal pleura while reducing friction.
B. It reduces alveolar surface tension and helps stabilize alveoli, especially at low lung volumes; this is enabled
because contraction flattens the dome, enlarges the thoracic cavity, and lowers alveolar pressure.
C. It reduces alveolar surface tension and helps stabilize alveoli, especially at low lung volumes; this is enabled
because molecules disrupt cohesive forces between water molecules, lowering the pressure required to keep small
alveoli open.
D. It reduces alveolar surface tension and helps stabilize alveoli, especially at low lung volumes; this is enabled
because its lobar organization accommodates branching bronchi and regional pulmonary tissue.
Correct Answer: C. It reduces alveolar surface tension and helps stabilize alveoli, especially at low lung volumes;
this is enabled because molecules disrupt cohesive forces between water molecules, lowering the pressure
required to keep small alveoli open.
Explanation: The correct pairing links pulmonary surfactant to this role: reduces alveolar surface tension and helps
stabilize alveoli, especially at low lung volumes, and to this mechanism: molecules disrupt cohesive forces between
water molecules, lowering the pressure required to keep small alveoli open. A correct function paired with the wrong
mechanism is still an incorrect description. The other options deliberately mix the role of pulmonary surfactant with
mechanisms that belong to different components.
Question 11. Which feature is most characteristic of interferon response?
A. it acts before microbes gain access to internal tissues
B. it is a cascade of plasma proteins that can be activated by several pathways
C. it is performed prominently by neutrophils and macrophages
D. virus-infected cells can release type I interferons early in infection
Correct Answer: D. virus-infected cells can release type I interferons early in infection
Explanation: The identifying feature is that virus-infected cells can release type I interferons early in infection. That
characteristic is consistent with interferon response and its normal role: helps neighboring cells resist viral replication
and coordinates antiviral defenses. The other findings are characteristic of different items and do not identify interferon
response as precisely.
Question 12. Which mechanism best explains the normal physiology of respiratory zone?
A. phagocytosis removes debris that escapes upper-airway filtration and mucociliary clearance
B. large total surface area and minimal diffusion distance support rapid gas transfer
C. very thin exchange surfaces are closely associated with pulmonary capillaries
D. its flattened shape minimizes diffusion distance between alveolar air and capillary blood
Correct Answer: C. very thin exchange surfaces are closely associated with pulmonary capillaries
Explanation: The correct mechanism is that very thin exchange surfaces are closely associated with pulmonary
capillaries. It explains the normal function of respiratory zone: contains the structures where pulmonary gas exchange
occurs. The other mechanisms belong to different structures or processes in the same broad system.
Question 13. Which structure or process is best identified by this description: it is influenced by surface
area, membrane thickness, diffusion coefficient, and partial-pressure difference?
A. carbon monoxide toxicity
B. pulmonary gas diffusion
C. peripheral chemoreceptor response
D. bicarbonate transport of carbon dioxide
Correct Answer: B. pulmonary gas diffusion
