Respiratory volumes MCQs With Answer

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Introduction: Respiratory volumes MCQs With Answer provide a focused way for B. Pharm students to master pulmonary function concepts essential for pharmacology, therapeutics, and clinical pharmacy practice. This Student-friendly guide covers tidal volume, vital capacity, total lung capacity, residual volume, FEV1/FVC ratios, dead space, diffusion, spirometry techniques and measurement methods. Clear explanations and targeted MCQs help reinforce interpretation of pulmonary function tests, disease patterns (obstructive vs restrictive), and drug effects on respiratory mechanics. Designed for rapid revision and exam prep, these questions emphasize clinically relevant values, formulas and testing procedures. Now let’s test your knowledge with 50 MCQs on this topic.

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

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

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

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

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

Correct Answer: VC = TV + IRV + ERV

Q3. Which lung volume cannot be measured by simple spirometry?

  • Tidal volume (TV)
  • Inspiratory reserve volume (IRV)
  • Residual volume (RV)
  • Expiratory reserve volume (ERV)

Correct Answer: Residual volume (RV)

Q4. Functional residual capacity (FRC) is equal to:

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

Correct Answer: RV + ERV

Q5. Total lung capacity (TLC) comprises which combination?

  • TVC + RV
  • TV + IRV + ERV + RV
  • FRC + IC
  • Only RV and ERV

Correct Answer: TV + IRV + ERV + RV

Q6. Which technique measures lung volumes including RV by body volume changes?

  • Helium dilution
  • Nitrogen washout
  • Body plethysmography
  • Spirometry

Correct Answer: Body plethysmography

Q7. What is the typical resting adult tidal volume (approx.)?

  • 100 mL
  • 500 mL
  • 1500 mL
  • 3000 mL

Correct Answer: 500 mL

Q8. Inspiratory capacity (IC) equals:

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

Correct Answer: TV + IRV

Q9. Which value is commonly reduced in restrictive lung disease?

  • Residual volume (RV) only
  • Total lung capacity (TLC)
  • Anatomic dead space
  • Peak expiratory flow (PEF) only

Correct Answer: Total lung capacity (TLC)

Q10. An increased residual volume is most characteristic of which disorder?

  • Pulmonary fibrosis
  • Obstructive diseases like COPD
  • Neuromuscular weakness
  • Chest wall restriction

Correct Answer: Obstructive diseases like COPD

Q11. FEV1/FVC ratio is used primarily to:

  • Estimate diffusion capacity
  • Differentiate obstructive from restrictive patterns
  • Calculate dead space
  • Measure oxygen saturation

Correct Answer: Differentiate obstructive from restrictive patterns

Q12. A patient with FEV1/FVC < 70% suggests:

  • Restrictive lung disease
  • Obstructive airway disease
  • Normal pulmonary function
  • Primary pulmonary hypertension

Correct Answer: Obstructive airway disease

Q13. Which measurement estimates alveolar ventilation taking dead space into account?

  • Minute ventilation (VE)
  • Alveolar ventilation (VA)
  • Inspiratory capacity
  • Chest wall compliance

Correct Answer: Alveolar ventilation (VA)

Q14. The anatomical dead space is best described as:

  • Alveoli not participating in gas exchange due to disease
  • Volume of conducting airways where no gas exchange occurs
  • Volume of trapped air after maximal expiration
  • The portion of lung participating in gas exchange

Correct Answer: Volume of conducting airways where no gas exchange occurs

Q15. The Bohr equation is used to calculate:

  • Diffusing capacity for carbon monoxide (DLCO)
  • Physiologic dead space
  • Static lung compliance
  • Maximal voluntary ventilation

Correct Answer: Physiologic dead space

Q16. Which factor decreases lung compliance?

  • Emphysema
  • Pulmonary fibrosis
  • Surfactant increase
  • Aging with loss of elastic recoil

Correct Answer: Pulmonary fibrosis

Q17. DLCO (diffusing capacity) is reduced in which condition?

  • Emphysema
  • Asthma with normal alveolar membrane
  • Increased pulmonary capillary blood volume
  • Polycythemia

Correct Answer: Emphysema

Q18. Which of the following increases physiologic dead space?

  • Pulmonary embolism
  • Bronchoconstriction in asthma
  • Increased cardiac output
  • High altitude acclimatization

Correct Answer: Pulmonary embolism

Q19. The normal approximate value for residual volume (RV) in adults is:

  • ~0.5 L
  • ~1.2 L
  • ~3.0 L
  • ~5.0 L

Correct Answer: ~1.2 L

Q20. Which test involves rebreathing a tracer gas to estimate FRC?

  • Chest X-ray
  • Helium dilution
  • Arterial blood gas
  • Pulse oximetry

Correct Answer: Helium dilution

Q21. Which capacity is reduced in obesity due to upward displacement of the diaphragm?

  • Tidal volume (TV)
  • Functional residual capacity (FRC)
  • Inspiratory reserve volume (IRV)
  • Residual volume (RV)

Correct Answer: Functional residual capacity (FRC)

Q22. Peak expiratory flow (PEF) primarily reflects:

  • Alveolar diffusion capacity
  • Large airway flow and effort
  • Residual volume size
  • Chest wall compliance only

Correct Answer: Large airway flow and effort

Q23. Which drug class acutely increases expiratory flow in obstructive disease?

  • Beta-2 agonists (bronchodilators)
  • ACE inhibitors
  • Loop diuretics
  • Anticoagulants

Correct Answer: Beta-2 agonists (bronchodilators)

Q24. In obstructive lung disease, the typical spirometry pattern shows:

  • Increased FEV1/FVC ratio
  • Reduced FEV1 with normal or reduced FVC and decreased FEV1/FVC ratio
  • Normal FEV1 and reduced TLC only
  • Increased TLC with normal FEV1

Correct Answer: Reduced FEV1 with normal or reduced FVC and decreased FEV1/FVC ratio

Q25. What happens to TLC in severe emphysema?

  • TLC is decreased
  • TLC is normal
  • TLC is increased due to air trapping
  • TLC equals RV only

Correct Answer: TLC is increased due to air trapping

Q26. Which parameter is most specific for small airway obstruction?

  • FEV1/FVC ratio
  • FEF25-75% (forced mid-expiratory flow)
  • Peak inspiratory flow
  • RV/TLC ratio

Correct Answer: FEF25-75% (forced mid-expiratory flow)

Q27. During pregnancy, which lung capacity typically decreases?

  • Inspiratory capacity (IC)
  • Functional residual capacity (FRC)
  • Tidal volume (TV)
  • Total lung capacity (TLC)

Correct Answer: Functional residual capacity (FRC)

Q28. The phrase “BTPS correction” refers to adjusting volumes for:

  • Blood temperature and pressure saturation
  • Body temperature, ambient pressure, saturated with water vapor
  • Barometric pressure, tidal saturation
  • Bronchodilator therapy phases

Correct Answer: Body temperature, ambient pressure, saturated with water vapor

Q29. Which change is expected with aging regarding lung volumes?

  • RV decreases and VC increases
  • RV increases and VC decreases
  • No change occurs with aging
  • TLC markedly increases

Correct Answer: RV increases and VC decreases

Q30. A reversibility test showing >12% and 200 mL increase in FEV1 after bronchodilator indicates:

  • Fixed airway obstruction
  • Significant bronchodilator responsiveness, suggesting asthma
  • Primary restrictive disease
  • Pulmonary embolism

Correct Answer: Significant bronchodilator responsiveness, suggesting asthma

Q31. Inspiratory reserve volume (IRV) is best described as:

  • Air remaining after normal expiration
  • Maximum additional air that can be inspired after a normal inspiration
  • Air remaining after maximal expiration
  • The same as tidal volume

Correct Answer: Maximum additional air that can be inspired after a normal inspiration

Q32. Which condition increases TLC due to hyperinflation?

  • Pulmonary fibrosis
  • Emphysema
  • Myasthenia gravis
  • Pneumothorax with collapse

Correct Answer: Emphysema

Q33. Which measurement reflects small airway obstruction early in disease?

  • DLCO
  • FEF25-75%
  • RV only
  • TLC only

Correct Answer: FEF25-75%

Q34. Which factor increases alveolar ventilation (VA) when tidal volume increases proportionally more than dead space?

  • Increasing respiratory rate only
  • Shallow breathing
  • Deep breathing with same rate
  • Complete airway obstruction

Correct Answer: Deep breathing with same rate

Q35. Nitrogen washout technique primarily measures:

  • FEV1
  • Functional residual capacity (FRC)
  • Peak expiratory flow
  • Inspiratory capacity

Correct Answer: Functional residual capacity (FRC)

Q36. Which of the following decreases residual volume?

  • Bronchial obstruction
  • Surgical pleurectomy with lung re-expansion
  • Severe emphysema
  • Chronic air trapping

Correct Answer: Surgical pleurectomy with lung re-expansion

Q37. Airway resistance is primarily determined by:

  • Lung diffusion capacity
  • Radius of the airways
  • Hemoglobin concentration
  • Alveolar PO2 only

Correct Answer: Radius of the airways

Q38. Which pattern is typical for restrictive lung disease on spirometry?

  • Normal or increased FEV1/FVC ratio with reduced TLC
  • Decreased FEV1/FVC ratio with increased TLC
  • Normal volumes with decreased DLCO only
  • Increased RV and normal TLC

Correct Answer: Normal or increased FEV1/FVC ratio with reduced TLC

Q39. In asthma, which lung volume often increases during an exacerbation?

  • Inspiratory capacity (IC)
  • Residual volume (RV)
  • Vital capacity (VC)
  • Diffusing capacity (DLCO)

Correct Answer: Residual volume (RV)

Q40. Which statement about spirometry is TRUE?

  • Spirometry directly measures residual volume (RV)
  • Spirometry measures FVC and FEV1 but not RV
  • Spirometry measures DLCO accurately
  • Spirometry is not effort dependent

Correct Answer: Spirometry measures FVC and FEV1 but not RV

Q41. The alveolar ventilation equation relates PaCO2 to which variables?

  • Minute ventilation and dead space fraction
  • Only tidal volume
  • Only hemoglobin concentration
  • Only oxygen consumption

Correct Answer: Minute ventilation and dead space fraction

Q42. Which disease typically shows preserved or increased DLCO?

  • Pulmonary fibrosis
  • Emphysema
  • Asthma
  • Pulmonary vascular disease

Correct Answer: Asthma

Q43. The term “air trapping” most directly increases which ratio?

  • RV/TLC
  • IC/FRC
  • FEV1/FVC
  • TV/ERV

Correct Answer: RV/TLC

Q44. Which intervention acutely reduces airway resistance in COPD?

  • Anticholinergic bronchodilators
  • Systemic corticosteroids only after weeks
  • Diuretics
  • Antibiotics

Correct Answer: Anticholinergic bronchodilators

Q45. Which of the following alters measured lung volumes in supine position compared to standing?

  • Increase in FRC due to diaphragmatic descent
  • Decrease in FRC due to abdominal contents pushing the diaphragm
  • No change in any lung volume
  • Increase in TLC only

Correct Answer: Decrease in FRC due to abdominal contents pushing the diaphragm

Q46. Which pulmonary function change is expected in neuromuscular weakness?

  • Increased TLC with normal RV
  • Reduced VC and reduced maximal inspiratory pressures
  • Isolated increase in DLCO
  • Increased FEV1/FVC ratio due to obstruction

Correct Answer: Reduced VC and reduced maximal inspiratory pressures

Q47. Which gas is used in DLCO testing as a surrogate to measure diffusion?

  • Oxygen (O2)
  • Carbon monoxide (CO)
  • Helium (He)
  • Nitrogen (N2)

Correct Answer: Carbon monoxide (CO)

Q48. A decreased FRC can lead to which consequence during anesthesia?

  • Improved oxygen reserve
  • Atelectasis and faster desaturation
  • Increased pulmonary compliance
  • Reduced risk of hypoxemia

Correct Answer: Atelectasis and faster desaturation

Q49. Which statement about inspiratory and expiratory reserve volumes is correct?

  • IRV is the maximal volume exhaled after a normal exhalation
  • ERV is the additional volume exhaled after a normal exhalation
  • IRV plus ERV equals TLC
  • ERV is normally larger than TLC

Correct Answer: ERV is the additional volume exhaled after a normal exhalation

Q50. In interpretation of PFTs for B. Pharm students, which concept is MOST important?

  • Knowing only numerical values without context
  • Correlating volumes, flows, clinical history, and responsiveness to therapy
  • Ignoring bronchodilator testing
  • Using DLCO values alone to diagnose all lung diseases

Correct Answer: Correlating volumes, flows, clinical history, and responsiveness to therapy

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