Lung capacities MCQs With Answer

Lung capacities MCQs With Answer provide B. Pharm students a focused way to master respiratory physiology, spirometry interpretation, and clinical correlations. This collection covers definitions, normal values, equations (VC, TLC, FRC), measurement techniques (spirometry, body plethysmography, gas dilution), and disease patterns (obstructive vs restrictive). Each question links practical pharmacy knowledge—drug effects on airflow, interpretation of FEV1/FVC, and implications for inhaled therapies—with core pulmonary concepts. Clear explanations and varied difficulty help reinforce learning for exams and clinical practice. Optimized for search terms like lung capacities, vital capacity, residual volume, spirometry, and pulmonary function tests. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the best definition of tidal volume (TV)?

• The maximum volume of air that can be expired after a maximal inspiration
• The volume of air moved into or out of the lungs during a normal relaxed breath
• The volume remaining in the lungs after a maximal expiration
• The sum of inspiratory reserve and expiratory reserve volumes

Correct Answer: The volume of air moved into or out of the lungs during a normal relaxed breath

Q2. Which equation correctly represents Vital Capacity (VC)?

• VC = TV + RV
• VC = IRV + TV + ERV
• VC = TLC – FRC
• VC = RV + ERV

Correct Answer: VC = IRV + TV + ERV

Q3. Total Lung Capacity (TLC) is defined as:

• The volume of air exchanged in one minute
• The volume remaining in lungs after normal expiration
• The maximum volume of air in the lungs after a maximal inspiration
• The volume of air exhaled in the first second of forced expiration

Correct Answer: The maximum volume of air in the lungs after a maximal inspiration

Q4. Which pair of volumes composes Functional Residual Capacity (FRC)?

• TV + IRV
• ERV + RV
• IRV + TV + ERV
• TLC – RV

Correct Answer: ERV + RV

Q5. Residual Volume (RV) is important clinically because:

• It can be measured by spirometry directly
• It prevents alveolar collapse and cannot be exhaled voluntarily
• It equals the tidal volume at rest
• It increases only during inspiration

Correct Answer: It prevents alveolar collapse and cannot be exhaled voluntarily

Q6. Which method directly measures residual volume and total lung capacity including trapped gas?

• Spirometry
• Body plethysmography
• Peak flow meter
• Single-breath nitrogen washout

Correct Answer: Body plethysmography

Q7. Spirometry can directly measure which of the following? (select best single answer)

• Residual volume
• Total lung capacity
• Forced vital capacity (FVC)
• Alveolar gas volume at end-expiration

Correct Answer: Forced vital capacity (FVC)

Q8. The normal FEV1/FVC ratio in a healthy adult is approximately:

• Below 50%
• 50–59%
• 60–69%
• 70–80% or higher

Correct Answer: 70–80% or higher

Q9. An obstructive pattern on spirometry is characterized by:

• Normal FEV1/FVC with reduced TLC
• Reduced FEV1/FVC ratio due to disproportionately decreased FEV1
• Increased FVC with normal FEV1
• Only reduced residual volume

Correct Answer: Reduced FEV1/FVC ratio due to disproportionately decreased FEV1

Q10. A restrictive lung disease pattern typically shows which spirometric change?

• Normal TLC with decreased FEV1/FVC
• Reduced TLC with normal or increased FEV1/FVC ratio
• Markedly increased RV with increased TLC
• Increased FEV1 and decreased FVC

Correct Answer: Reduced TLC with normal or increased FEV1/FVC ratio

Q11. Inspiratory Capacity (IC) equals:

• TV + ERV
• IRV + TV
• TLC – RV
• FRC + TV

Correct Answer: IRV + TV

Q12. If TV = 500 mL, IRV = 3000 mL, and ERV = 1100 mL, what is the VC?

• 4600 mL
• 2100 mL
• 5000 mL
• 1100 mL

Correct Answer: 4600 mL

Q13. Which gas dilution technique underestimates TLC in patients with significant airway obstruction?

• Body plethysmography
• Helium dilution
• Chest X-ray
• Ultrasound lung scanning

Correct Answer: Helium dilution

Q14. Diffusing capacity for carbon monoxide (DLCO) primarily assesses:

• Airflow limitation at the level of bronchi
• Alveolar-capillary membrane gas transfer efficiency
• Residual volume magnitude
• Chest wall compliance only

Correct Answer: Alveolar-capillary membrane gas transfer efficiency

Q15. Which change would you expect with aging in lung capacities?

• Increase in VC and decrease in RV
• Decrease in compliance and increase in FEV1
• Decrease in elastic recoil leading to increased RV and FRC
• Marked increase in TLC in elderly

Correct Answer: Decrease in elastic recoil leading to increased RV and FRC

Q16. The primary clinical utility of measuring FEV1 before and after bronchodilator administration is to:

• Detect increased TLC
• Assess reversibility of airway obstruction
• Calculate alveolar oxygen tension
• Measure residual volume directly

Correct Answer: Assess reversibility of airway obstruction

Q17. Peak expiratory flow rate (PEFR) primarily reflects:

• Small airway patency only
• Large airway function and effort-dependent flow
• Total lung capacity exclusively
• Diffusion across alveolar membrane

Correct Answer: Large airway function and effort-dependent flow

Q18. A reduced TLC with normal RV and normal FEV1/FVC suggests which category?

• Obstructive disease
• Restrictive disease
• Mixed obstructive-restrictive disease
• Primary neuromuscular weakness only

Correct Answer: Restrictive disease

Q19. Which of these medications would most likely improve FEV1 in an asthmatic patient acutely?

• Inhaled short-acting beta2 agonist (e.g., salbutamol)
• Systemic antibiotics
• ACE inhibitor
• Loop diuretic

Correct Answer: Inhaled short-acting beta2 agonist (e.g., salbutamol)

Q20. During spirometry, the slow vital capacity (SVC) compared to forced vital capacity (FVC) in obstructive disease is often:

• Smaller than FVC
• Equal to RV
• Larger than FVC due to airway collapse in forced maneuver
• Identical in all subjects

Correct Answer: Larger than FVC due to airway collapse in forced maneuver

Q21. Which statement about residual volume (RV) in obstructive lung disease is correct?

• RV is typically decreased due to airway dilation
• RV is unchanged compared to healthy subjects
• RV is often increased because of air trapping
• RV equals inspiratory capacity in COPD

Correct Answer: RV is often increased because of air trapping

Q22. What is the clinical significance of the closing capacity exceeding functional residual capacity (FRC)?

• It predisposes to airway closure during quiet breathing and V/Q mismatch
• It improves oxygenation during sleep
• It indicates increased chest wall compliance only
• It reflects improved alveolar recruitment

Correct Answer: It predisposes to airway closure during quiet breathing and V/Q mismatch

Q23. Which factor decreases functional residual capacity (FRC)?

• Supine position
• Bronchodilation
• Aging
• Obesity

Correct Answer: Supine position

Q24. The inspiratory reserve volume (IRV) refers to:

• The volume exhaled during a forced expiration
• The additional volume that can be inspired after a normal inspiration
• The volume remaining after maximal expiration
• The sum of RV and ERV

Correct Answer: The additional volume that can be inspired after a normal inspiration

Q25. In COPD, which of the following is commonly observed?

• Decreased RV and decreased TLC
• Increased RV, increased TLC, and decreased FEV1/FVC
• Normal RV with increased FEV1/FVC
• Isolated decreased VC only

Correct Answer: Increased RV, increased TLC, and decreased FEV1/FVC

Q26. Maximum voluntary ventilation (MVV) evaluates:

• Static lung volumes only
• Dynamic ventilatory capacity and respiratory muscle endurance
• Alveolar oxygen tension directly
• Only the residual volume

Correct Answer: Dynamic ventilatory capacity and respiratory muscle endurance

Q27. Which of the following best describes alveolar ventilation (VA)?

• VA = Respiratory rate × Total lung capacity
• VA = Respiratory rate × (TV − anatomical dead space)
• VA = TV + RV
• VA = FRC − RV

Correct Answer: VA = Respiratory rate × (TV − anatomical dead space)

Q28. Which clinical condition is most likely to produce a decreased DLCO?

• Pulmonary fibrosis
• Asthma without emphysema
• Pregnancy
• Left-to-right cardiac shunt

Correct Answer: Pulmonary fibrosis

Q29. The allowance for physiologic dead space affects which lung capacity calculation?

• TLC measured by plethysmography only
• Alveolar ventilation and effective gas exchange calculations
• Residual volume is increased directly
• Inspiratory capacity becomes zero

Correct Answer: Alveolar ventilation and effective gas exchange calculations

Q30. Which is a correct relationship between lung volumes?

• TLC = VC − RV
• FRC = TLC + RV
• TLC = VC + RV
• VC = RV + TLC

Correct Answer: TLC = VC + RV

Q31. In a mixed obstructive-restrictive pattern, spirometry typically shows:

• Normal TLC and normal FEV1/FVC
• Reduced TLC and reduced FEV1/FVC
• Increased TLC and increased FEV1/FVC
• Only increased RV with normal FEV1

Correct Answer: Reduced TLC and reduced FEV1/FVC

Q32. Which bedside test provides a simple estimate of expiratory flow and can be useful for monitoring asthma control?

• DLCO test
• Peak expiratory flow (PEF) meter
• Body plethysmography
• Arterial blood gas analysis

Correct Answer: Peak expiratory flow (PEF) meter

Q33. Which statement about forced expiratory flow 25–75% (FEF25–75) is true?

• It primarily reflects large airway function only
• It can be an early indicator of small airway disease
• It is used to measure diffusion capacity
• It directly measures residual volume

Correct Answer: It can be an early indicator of small airway disease

Q34. Which physiological change is commonly seen during pregnancy with respect to lung volumes?

• Marked increase in residual volume
• Decrease in functional residual capacity due to upward displacement of diaphragm
• Large decrease in tidal volume
• Increase in TLC beyond normal adult values

Correct Answer: Decrease in functional residual capacity due to upward displacement of diaphragm

Q35. Nitrogen washout technique measures which volume effectively?

• Total lung capacity in obstructive disease without error
• Functional residual capacity by equilibrating and washing out nitrogen from ventilated areas
• Residual volume in non-communicating spaces
• DLCO directly

Correct Answer: Functional residual capacity by equilibrating and washing out nitrogen from ventilated areas

Q36. In acute bronchospasm, immediate spirometry most likely shows:

• Increased FEV1 and increased FVC
• Reduced FEV1 and reduced FEV1/FVC ratio
• Only increased TLC with normal flows
• Only decreased RV with increased FEV1/FVC

Correct Answer: Reduced FEV1 and reduced FEV1/FVC ratio

Q37. Which of the following will decrease vital capacity?

• Diaphragmatic paralysis
• Inhaled bronchodilator therapy
• Training that strengthens inspiratory muscles
• Deep breathing exercises

Correct Answer: Diaphragmatic paralysis

Q38. What is the best explanation for increased TLC in emphysema?

• Increased chest wall stiffness reduces lung volume
• Destruction of alveolar walls increases lung compliance and air trapping
• Enhanced surfactant production enlarges lung volume
• Compression atelectasis increases TLC

Correct Answer: Destruction of alveolar walls increases lung compliance and air trapping

Q39. Which parameter best predicts perioperative pulmonary risk related to ventilatory capacity?

• Resting tidal volume alone
• Maximum voluntary ventilation (MVV)
• Residual volume only
• DLCO unrelated to surgery

Correct Answer: Maximum voluntary ventilation (MVV)

Q40. Which effect would centrally acting opioids have on measured lung capacities?

• Increase in FRC due to bronchodilation
• Minimal direct change in static lung volumes but potential hypoventilation reducing alveolar ventilation
• Direct reduction in residual volume by stimulating expiratory muscles
• Increase in DLCO by improving perfusion

Correct Answer: Minimal direct change in static lung volumes but potential hypoventilation reducing alveolar ventilation

Q41. What is the typical inspiratory capacity (IC) in a healthy adult if TV = 500 mL and IRV = 3000 mL?

• 3500 mL
• 500 mL
• 3000 mL
• 4500 mL

Correct Answer: 3500 mL

Q42. Which of these best describes a mixed obstructive and restrictive physiology on pulmonary function testing?

• Normal TLC, normal FEV1/FVC, isolated reduced DLCO
• Reduced TLC and reduced FEV1/FVC ratio, with reduced DLCO
• Increased TLC with normal flows
• Only increased residual volume without other changes

Correct Answer: Reduced TLC and reduced FEV1/FVC ratio, with reduced DLCO

Q43. For drug dosage and inhalation therapy selection, why is understanding lung volumes important for a pharmacist?

• It determines systemic drug metabolism only
• It helps predict deposition, clearance, and efficacy of inhaled medications
• It is unrelated to inhaled drug delivery
• It only matters for IV drug dosing

Correct Answer: It helps predict deposition, clearance, and efficacy of inhaled medications

Q44. Which physiologic maneuver is used to obtain a maximum voluntary ventilation (MVV) measurement?

• Rapid deep breaths for a set time (e.g., 12–15 seconds)
• A single maximal inspiratory maneuver only
• Holding breath for 30 seconds
• Slow tidal breathing for 5 minutes

Correct Answer: Rapid deep breaths for a set time (e.g., 12–15 seconds)

Q45. In which condition is FVC often reduced but FEV1/FVC ratio preserved or increased?

• Obstructive lung disease like COPD
• Restrictive lung disease such as pulmonary fibrosis
• Upper airway obstruction only
• Acute bronchospasm that is reversible

Correct Answer: Restrictive lung disease such as pulmonary fibrosis

Q46. Which statement about static vs dynamic lung volumes is true?

• Static volumes (e.g., RV, TLC) are measured during forced maneuvers only
• Dynamic measurements (e.g., FEV1) depend on flow rates and effort
• Static volumes always change immediately with bronchodilator
• Dynamic volumes reflect alveolar-capillary gas transfer directly

Correct Answer: Dynamic measurements (e.g., FEV1) depend on flow rates and effort

Q47. How does obesity typically affect lung capacities?

• Increases FRC and TLC substantially
• Decreases FRC and ERV due to chest wall and abdominal mass effect
• Only increases RV
• No measurable impact on pulmonary function

Correct Answer: Decreases FRC and ERV due to chest wall and abdominal mass effect

Q48. Which volume or capacity cannot be measured by simple spirometry?

• Forced vital capacity (FVC)
• Tidal volume (TV)
• Total lung capacity (TLC)
• Expiratory reserve volume (ERV)

Correct Answer: Total lung capacity (TLC)

Q49. In restrictive lung disease, why might DLCO be reduced?

• Because of increased alveolar volume and capillary blood volume
• Due to thickening of alveolar-capillary membrane and loss of alveolar surface area
• Because airways are hyperresponsive like asthma
• Only due to airway mucus plugging

Correct Answer: Due to thickening of alveolar-capillary membrane and loss of alveolar surface area

Q50. Which practical tip should a pharmacist keep in mind when advising patients on inhaler techniques based on lung function?

• All patients should use the same inhaler technique regardless of disease
• Device choice and technique should match patient’s inspiratory flow and lung capacity
• Diskus and dry powder inhalers require no inspiratory effort
• Metered dose inhalers are always superior for patients with low inspiratory flow

Correct Answer: Device choice and technique should match patient’s inspiratory flow and lung capacity

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com