BMS 300 EXAM 4 [2026] UPDATED ACTUAL Exam
Questions and Answers | Frequently Tested Questions
Questions with Verified Answers & Detailed Explanations
FORMATTING LEGEND:
• Bold Italic = Correct Answer
• Italic = Rationale/Explanation
• QUESTION 1
Which muscle is primarily responsible for forced expiration?
• A) Diaphragm
B) External intercostals
C) Abdominal muscles
D) Scalene muscles
•
• CORRECT ANSWER: C) Abdominal muscles
• Rationale: Forced expiration is primarily achieved by contraction of the
abdominal muscles, which increases intra-abdominal pressure and
pushes the diaphragm upward, compressing the lungs. The diaphragm
and external intercostals are muscles of inspiration.
•
,• QUESTION 2
What is the term for the volume of air remaining in the lungs after a
forced expiration?
• A) Tidal volume
B) Residual volume
C) Vital capacity
D) Expiratory reserve volume
•
• CORRECT ANSWER: B) Residual volume
• Rationale: Residual volume is the volume of air remaining in the lungs
after a maximum forced expiration. It cannot be measured by
spirometry and prevents lung collapse. Tidal volume is normal
breathing, vital capacity is maximum exhalation after maximum
inhalation.
•
• QUESTION 3
Which of the following decreases the affinity of hemoglobin for
oxygen?
• A) Increased pH
B) Decreased temperature
C) Increased 2,3-BPG
D) Decreased CO₂
•
• CORRECT ANSWER: C) Increased 2,3-BPG
,• Rationale: 2,3-BPG (2,3-bisphosphoglycerate) decreases hemoglobin's
affinity for oxygen, shifting the oxygen-hemoglobin dissociation curve
to the right. This promotes oxygen unloading to tissues. Increased pH,
decreased temperature, and decreased CO₂ all increase hemoglobin's
affinity for O₂ (left shift).
•
• QUESTION 4
Pulmonary fibrosis would cause which of the following changes?
• A) Decreased compliance and increased elastic recoil
B) Increased compliance and decreased elastic recoil
C) No change in compliance
D) Increased compliance and increased elastic recoil
•
• CORRECT ANSWER: A) Decreased compliance and increased
elastic recoil
• Rationale: Pulmonary fibrosis causes stiffening of lung tissue,
decreasing compliance (lungs become harder to inflate) and increasing
elastic recoil (lungs pull inward more strongly). This makes breathing
more difficult and reduces lung volumes.
•
• QUESTION 5
Which of the following is true about the Haldane effect?
• A) Deoxygenated hemoglobin has a higher affinity for CO₂ than
oxygenated hemoglobin
B) Oxygenated hemoglobin has a higher affinity for CO₂ than
deoxygenated hemoglobin
, C) CO₂ has no effect on hemoglobin
D) Increased CO₂ decreases hemoglobin's affinity for O₂
•
• CORRECT ANSWER: A) Deoxygenated hemoglobin has a higher
affinity for CO₂ than oxygenated hemoglobin
• Rationale: The Haldane effect states that deoxygenated hemoglobin
has a higher affinity for CO₂ than oxygenated hemoglobin. This
facilitates CO₂ transport from tissues to the lungs. The Bohr effect
describes CO₂'s effect on O₂ affinity.
•
• QUESTION 6
The partial pressure of oxygen in arterial blood (PaO₂) is normally
approximately:
• A) 40 mm Hg
B) 75 mm Hg
C) 100 mm Hg
D) 160 mm Hg
•
• CORRECT ANSWER: C) 100 mm Hg
• Rationale: Normal PaO₂ is approximately 100 mm Hg. PaCO₂ is
approximately 40 mm Hg. Alveolar PO₂ is approximately 104 mm Hg,
and atmospheric PO₂ is 160 mm Hg.
•
Questions and Answers | Frequently Tested Questions
Questions with Verified Answers & Detailed Explanations
FORMATTING LEGEND:
• Bold Italic = Correct Answer
• Italic = Rationale/Explanation
• QUESTION 1
Which muscle is primarily responsible for forced expiration?
• A) Diaphragm
B) External intercostals
C) Abdominal muscles
D) Scalene muscles
•
• CORRECT ANSWER: C) Abdominal muscles
• Rationale: Forced expiration is primarily achieved by contraction of the
abdominal muscles, which increases intra-abdominal pressure and
pushes the diaphragm upward, compressing the lungs. The diaphragm
and external intercostals are muscles of inspiration.
•
,• QUESTION 2
What is the term for the volume of air remaining in the lungs after a
forced expiration?
• A) Tidal volume
B) Residual volume
C) Vital capacity
D) Expiratory reserve volume
•
• CORRECT ANSWER: B) Residual volume
• Rationale: Residual volume is the volume of air remaining in the lungs
after a maximum forced expiration. It cannot be measured by
spirometry and prevents lung collapse. Tidal volume is normal
breathing, vital capacity is maximum exhalation after maximum
inhalation.
•
• QUESTION 3
Which of the following decreases the affinity of hemoglobin for
oxygen?
• A) Increased pH
B) Decreased temperature
C) Increased 2,3-BPG
D) Decreased CO₂
•
• CORRECT ANSWER: C) Increased 2,3-BPG
,• Rationale: 2,3-BPG (2,3-bisphosphoglycerate) decreases hemoglobin's
affinity for oxygen, shifting the oxygen-hemoglobin dissociation curve
to the right. This promotes oxygen unloading to tissues. Increased pH,
decreased temperature, and decreased CO₂ all increase hemoglobin's
affinity for O₂ (left shift).
•
• QUESTION 4
Pulmonary fibrosis would cause which of the following changes?
• A) Decreased compliance and increased elastic recoil
B) Increased compliance and decreased elastic recoil
C) No change in compliance
D) Increased compliance and increased elastic recoil
•
• CORRECT ANSWER: A) Decreased compliance and increased
elastic recoil
• Rationale: Pulmonary fibrosis causes stiffening of lung tissue,
decreasing compliance (lungs become harder to inflate) and increasing
elastic recoil (lungs pull inward more strongly). This makes breathing
more difficult and reduces lung volumes.
•
• QUESTION 5
Which of the following is true about the Haldane effect?
• A) Deoxygenated hemoglobin has a higher affinity for CO₂ than
oxygenated hemoglobin
B) Oxygenated hemoglobin has a higher affinity for CO₂ than
deoxygenated hemoglobin
, C) CO₂ has no effect on hemoglobin
D) Increased CO₂ decreases hemoglobin's affinity for O₂
•
• CORRECT ANSWER: A) Deoxygenated hemoglobin has a higher
affinity for CO₂ than oxygenated hemoglobin
• Rationale: The Haldane effect states that deoxygenated hemoglobin
has a higher affinity for CO₂ than oxygenated hemoglobin. This
facilitates CO₂ transport from tissues to the lungs. The Bohr effect
describes CO₂'s effect on O₂ affinity.
•
• QUESTION 6
The partial pressure of oxygen in arterial blood (PaO₂) is normally
approximately:
• A) 40 mm Hg
B) 75 mm Hg
C) 100 mm Hg
D) 160 mm Hg
•
• CORRECT ANSWER: C) 100 mm Hg
• Rationale: Normal PaO₂ is approximately 100 mm Hg. PaCO₂ is
approximately 40 mm Hg. Alveolar PO₂ is approximately 104 mm Hg,
and atmospheric PO₂ is 160 mm Hg.
•
