1. Which structure serves as the main site of gas exchange?
(A) Bronchi
(B) Trachea
(C) Alveoli
(D) Pleura
2. Which muscle is the primary muscle of breathing?
(A) Diaphragm
(B) Sternocleidomastoid
(C) Intercostal muscles
(D) Abdominal muscles
3. The normal respiratory rate in adults is:
(A) 8–12 breaths/min
(B) 12–20 breaths/min
(C) 20–28 breaths/min
(D) 30–40 breaths/min
4. Which lung has two lobes?
(A) Right lung
(B) Left lung
(C) Both lungs
(D) None
5. Surfactant is secreted by:
(A) Type I pneumocytes
(B) Type II pneumocytes
(C) Macrophages
(D) Ciliated epithelium
6. Which gas mainly regulates respiration?
(A) O₂
(B) CO₂
(C) N₂
(D) H₂O vapor
7. Which part of the brain controls basic rhythm of respiration?
(A) Cerebrum
(B) Cerebellum
(C) Medulla oblongata
(D) Hypothalamus
8. What is the normal tidal volume in adults?
(A) 150 ml
(B) 300 ml
(C) 500 ml
(D) 1000 ml
9. Which structure prevents food from entering trachea?
(A) Uvula
(B) Epiglottis
(C) Tonsils
(D) Vocal cords
10. Which lung volume cannot be measured by spirometry?
(A) Residual volume
(B) Tidal volume
(C) Expiratory reserve volume
(D) Inspiratory reserve volume
11. Which law explains the pressure-volume relationship in breathing?
(A) Boyle’s law
(B) Charles’s law
(C) Dalton’s law
(D) Henry’s law
12. Which nerve supplies the diaphragm?
(A) Vagus nerve
(B) Phrenic nerve
(C) Glossopharyngeal nerve
(D) Intercostal nerves
13. Which structure is known as the “windpipe”?
(A) Bronchus
(B) Trachea
(C) Larynx
(D) Alveolus
14. The left lung has how many lobes?
(A) 1
(B) 2
(C) 3
(D) 4
15. What is the approximate alveolar surface area in adult lungs?
(A) 20 m²
(B) 50 m²
(C) 70 m²
(D) 200 m²
16. The conducting zone of respiratory tract includes:
(A) Alveoli
(B) Alveolar ducts
(C) Trachea and bronchi
(D) Pulmonary capillaries
17. Oxygen is transported in blood primarily:
(A) Dissolved in plasma
(B) Bound to hemoglobin
(C) As bicarbonate
(D) As carbaminohemoglobin
18. Cyanosis becomes clinically evident when oxygen saturation falls below:
(A) 95%
(B) 90%
(C) 85%
(D) 80%
19. Which pleura directly covers the lungs?
(A) Parietal pleura
(B) Visceral pleura
(C) Pleural cavity
(D) None
20. The lung volume left after normal expiration is:
(A) Residual volume
(B) Tidal volume
(C) Functional residual capacity
(D) Vital capacity
21. Which condition is characterized by destruction of alveoli?
(A) Asthma
(B) Emphysema
(C) Tuberculosis
(D) Pneumonia
22. Which test is used to measure lung volumes and capacities?
(A) Spirometry
(B) ECG
(C) Echocardiography
(D) X-ray
23. Which gas diffuses fastest across alveolar membrane?
(A) O₂
(B) CO₂
(C) N₂
(D) He
24. Which respiratory disease is due to Mycobacterium tuberculosis?
(A) Asthma
(B) Tuberculosis
(C) COPD
(D) Pneumothorax
25. Which structure separates thoracic cavity from abdominal cavity?
(A) Pleura
(B) Mediastinum
(C) Diaphragm
(D) Pericardium
26. Which condition shows a barrel-shaped chest?
(A) Asthma
(B) Emphysema
(C) Pneumonia
(D) Pleural effusion
27. Which is a restrictive lung disease?
(A) Asthma
(B) Pulmonary fibrosis
(C) Chronic bronchitis
(D) Emphysema
28. The majority of CO₂ is carried in blood as:
(A) Dissolved CO₂
(B) Carbaminohemoglobin
(C) Bicarbonate ions
(D) Bound to plasma proteins
29. Which respiratory sound is typical in asthma?
(A) Crackles
(B) Wheezing
(C) Stridor
(D) Rhonchi
30. Which structure is called the voice box?
(A) Trachea
(B) Larynx
(C) Pharynx
(D) Epiglottis
31. Which condition is caused by lack of surfactant in newborns?
(A) Asthma
(B) Pneumonia
(C) Neonatal respiratory distress syndrome
(D) Tuberculosis
32. Which type of pneumothorax is life-threatening?
(A) Open
(B) Simple
(C) Tension
(D) Spontaneous
33. Which law explains diffusion of gases in alveoli?
(A) Boyle’s law
(B) Dalton’s law
(C) Henry’s law
(D) Charles’s law
34. Which gas law describes partial pressures of gases?
(A) Dalton’s law
(B) Henry’s law
(C) Boyle’s law
(D) Charles’s law
35. Which structure is the narrowest part of airway in children?
(A) Trachea
(B) Bronchi
(C) Cricoid cartilage
(D) Alveoli
36. Which lung disease shows “honeycomb lung” on CT?
(A) Emphysema
(B) Pulmonary fibrosis
(C) Tuberculosis
(D) Asthma
37. Which condition is defined as collapse of alveoli?
(A) Pleural effusion
(B) Atelectasis
(C) Pneumonia
(D) Pneumothorax
38. Which respiratory center responds primarily to hypoxia?
(A) Medulla
(B) Pons
(C) Peripheral chemoreceptors
(D) Cortex
39. Which lung disease is known as “blue bloater”?
(A) Asthma
(B) Chronic bronchitis
(C) Emphysema
(D) Pneumonia
40. Which is known as “pink puffer”?
(A) Asthma
(B) Chronic bronchitis
(C) Emphysema
(D) Tuberculosis
41. Which condition shows consolidation in lungs?
(A) Pneumonia
(B) Asthma
(C) Emphysema
(D) COPD
42. Which condition involves air in pleural cavity?
(A) Pneumothorax
(B) Pleural effusion
(C) Pulmonary embolism
(D) Pulmonary edema
43. Which condition is characterized by fluid in pleural space?
(A) Pleural effusion
(B) Pneumothorax
(C) Atelectasis
(D) Pulmonary fibrosis
44. Which is the gold standard test for pulmonary embolism?
(A) Chest X-ray
(B) CT pulmonary angiography
(C) MRI
(D) Ultrasound
45. Which breathing pattern is deep and labored, seen in DKA?
(A) Cheyne-Stokes
(B) Kussmaul respiration
(C) Apnea
(D) Tachypnea
46. Which gas has the highest solubility in blood?
(A) O₂
(B) CO₂
(C) N₂
(D) He
47. Which respiratory parameter is reduced in obstructive disease?
(A) Residual volume
(B) FEV1
(C) Vital capacity
(D) Total lung capacity
48. Which condition shows productive cough for >3 months/year, 2 consecutive years?
(A) Asthma
(B) Chronic bronchitis
(C) Tuberculosis
(D) Emphysema
49. Which lung disease commonly affects miners due to coal dust?
(A) Asbestosis
(B) Silicosis
(C) Anthracosis
(D) Tuberculosis
50. Which test measures arterial oxygen saturation non-invasively?
(A) ABG
(B) Spirometry
(C) Pulse oximetry
(D) Peak flow meter