GNM 1st Year | Anatomy & Physiology
Practice these multiple-choice questions on the respiratory system to revise important concepts for nursing examinations.
MCQs on Respiratory System
These questions cover the respiratory organs, air passages, lungs, alveoli, breathing, gas exchange, transport of respiratory gases and regulation of respiration. Each question is followed by the correct answer and a brief explanation.
1. What is the main function of the respiratory system?
A. Digestion of food
B. Exchange of oxygen and carbon dioxide
C. Production of urine
D. Production of bile
Answer: B. Exchange of oxygen and carbon dioxide
Explanation: The respiratory system brings oxygen into the body and removes carbon dioxide.
2. Which structure is commonly called the voice box?
A. Pharynx
B. Larynx
C. Trachea
D. Bronchus
Answer: B. Larynx
Explanation: The larynx contains the vocal cords and plays an important role in voice production.
3. The windpipe is also known as the:
A. Pharynx
B. Trachea
C. Larynx
D. Bronchiole
Answer: B. Trachea
Explanation: The trachea is the airway that carries air from the larynx toward the bronchi.
4. Where does gas exchange mainly occur?
A. Trachea
B. Bronchi
C. Alveoli
D. Pharynx
Answer: C. Alveoli
Explanation: Alveoli are microscopic air sacs surrounded by pulmonary capillaries and are the main sites of gas exchange.
5. How many lobes does the right lung have?
A. One
B. Two
C. Three
D. Four
Answer: C. Three
Explanation: The right lung has superior, middle and inferior lobes.
6. How many lobes does the left lung have?
A. One
B. Two
C. Three
D. Four
Answer: B. Two
Explanation: The left lung has superior and inferior lobes and is slightly smaller because of the position of the heart.
7. What is the main muscle of quiet breathing?
A. Biceps
B. Diaphragm
C. Deltoid
D. Trapezius
Answer: B. Diaphragm
Explanation: The diaphragm is the major muscle involved in normal quiet inspiration.
8. During normal inspiration, the diaphragm:
A. Relaxes and moves upward
B. Contracts and moves downward
C. Stops moving
D. Contracts and moves upward
Answer: B. Contracts and moves downward
Explanation: Diaphragmatic contraction increases thoracic volume and helps draw air into the lungs.
9. During quiet expiration, the diaphragm:
A. Contracts and moves downward
B. Relaxes and moves upward
C. Remains completely fixed
D. Moves sideways
Answer: B. Relaxes and moves upward
Explanation: Relaxation of the diaphragm contributes to the reduction in thoracic volume during quiet expiration.
10. Which structure divides into the right and left main bronchi?
A. Pharynx
B. Larynx
C. Trachea
D. Alveolus
Answer: C. Trachea
Explanation: The lower end of the trachea divides into the right and left main bronchi.
11. Which membrane covers the surface of the lungs?
A. Peritoneum
B. Visceral pleura
C. Pericardium
D. Meninges
Answer: B. Visceral pleura
Explanation: The visceral pleura closely covers the lung surface, while the parietal pleura lines the thoracic cavity.
12. Which membrane lines the inner surface of the thoracic cavity?
A. Visceral pleura
B. Parietal pleura
C. Peritoneum
D. Endocardium
Answer: B. Parietal pleura
Explanation: The parietal pleura lines the thoracic cavity.
13. What is the primary function of the alveoli?
A. Produce mucus
B. Exchange respiratory gases
C. Produce red blood cells
D. Digest proteins
Answer: B. Exchange respiratory gases
Explanation: Oxygen and carbon dioxide are exchanged between alveolar air and pulmonary capillary blood across the respiratory membrane.
14. Most oxygen in the blood is transported:
A. Dissolved freely in plasma
B. Bound to haemoglobin
C. As bicarbonate
D. Inside platelets
Answer: B. Bound to haemoglobin
Explanation: Most oxygen is transported attached to haemoglobin in red blood cells.
15. Most carbon dioxide in the blood is transported as:
A. Oxygen
B. Bicarbonate ions
C. Haemoglobin only
D. Nitrogen
Answer: B. Bicarbonate ions
Explanation: Most carbon dioxide is converted into bicarbonate and transported in the blood in this form.
16. External respiration refers to gas exchange between:
A. Blood and body tissues
B. Alveoli and pulmonary blood
C. Stomach and blood
D. Kidneys and blood
Answer: B. Alveoli and pulmonary blood
Explanation: External respiration is the exchange of oxygen and carbon dioxide between alveolar air and pulmonary capillary blood.
17. Internal respiration refers to gas exchange between:
A. Alveoli and blood
B. Blood and body tissues
C. Nose and pharynx
D. Trachea and bronchi
Answer: B. Blood and body tissues
Explanation: Internal respiration occurs between systemic blood and body tissues.
18. The movement of gases across the respiratory membrane occurs mainly by:
A. Active transport
B. Diffusion
C. Filtration
D. Osmosis
Answer: B. Diffusion
Explanation: Oxygen and carbon dioxide move across the respiratory membrane down their partial-pressure gradients.
19. Which structure helps prevent food from entering the lower airway during swallowing?
A. Epiglottis
B. Alveolus
C. Bronchiole
D. Pleura
Answer: A. Epiglottis
Explanation: The epiglottis helps protect the airway during swallowing.
20. Which part of the respiratory tract is shared with the digestive system?
A. Pharynx
B. Trachea
C. Bronchi
D. Alveoli
Answer: A. Pharynx
Explanation: The pharynx serves as a common passage for both respiratory and digestive pathways.
21. What is the main function of the nasal cavity in respiration?
A. Pump blood
B. Filter, warm and humidify inspired air
C. Produce bile
D. Absorb nutrients
Answer: B. Filter, warm and humidify inspired air
Explanation: The nasal cavity helps condition incoming air before it reaches the lower respiratory tract.
22. Which of the following is part of the lower respiratory tract?
A. Nose
B. Pharynx
C. Trachea
D. Nasal cavity
Answer: C. Trachea
Explanation: The lower respiratory tract includes the larynx, trachea, bronchi, bronchioles and lungs.
23. Which structure contains the vocal cords?
A. Pharynx
B. Larynx
C. Trachea
D. Bronchus
Answer: B. Larynx
Explanation: The larynx contains the vocal cords and is involved in sound production.
24. What is the primary purpose of cartilage rings in the trachea?
A. Produce oxygen
B. Keep the airway open
C. Exchange gases
D. Filter blood
Answer: B. Keep the airway open
Explanation: The cartilage rings provide structural support and help prevent collapse of the trachea.
25. Which structure is directly surrounded by pulmonary capillaries for gas exchange?
A. Alveoli
B. Trachea
C. Pharynx
D. Larynx
Answer: A. Alveoli
Explanation: A dense network of pulmonary capillaries surrounds the alveoli, allowing efficient gas exchange.
26. The respiratory centres that regulate breathing are mainly located in the:
A. Brainstem
B. Kidney
C. Liver
D. Pancreas
Answer: A. Brainstem
Explanation: Respiratory centres in the brainstem coordinate the basic rhythm and regulation of breathing.
27. Which factor is particularly important in the normal regulation of ventilation?
A. Blood carbon dioxide level
B. Hair colour
C. Blood group only
D. Body height
Answer: A. Blood carbon dioxide level
Explanation: Changes in carbon dioxide and the resulting changes in blood pH strongly influence respiratory drive under normal conditions.
28. What happens to thoracic volume during normal inspiration?
A. It decreases
B. It increases
C. It remains unchanged
D. It becomes zero
Answer: B. It increases
Explanation: Contraction of the diaphragm and external intercostal muscles increases thoracic volume during inspiration.
29. Which of the following is a function of the respiratory system besides gas exchange?
A. Voice production
B. Urine formation
C. Insulin production
D. Bile storage
Answer: A. Voice production
Explanation: Air passing through the larynx allows the vocal cords to produce sound.
30. Which sequence correctly describes the pathway of inspired air?
A. Nose → pharynx → larynx → trachea → bronchi → bronchioles → alveoli
B. Nose → oesophagus → stomach → lungs
C. Nose → larynx → stomach → bronchi
D. Nose → kidney → trachea → alveoli
Answer: A. Nose → pharynx → larynx → trachea → bronchi → bronchioles → alveoli
Explanation: This is the normal pathway followed by inspired air from the upper airway to the respiratory portions of the lungs.
Quick Revision
- Right lung: Three lobes.
- Left lung: Two lobes.
- Alveoli: Main sites of gas exchange.
- Diaphragm: Main muscle of quiet breathing.
- Inspiration: Air enters the lungs.
- Expiration: Air leaves the lungs.
- Oxygen: Mainly transported by haemoglobin.
- Carbon dioxide: Mainly transported as bicarbonate.
- External respiration: Alveoli ↔ pulmonary blood.
- Internal respiration: Blood ↔ body tissues.
Related Study Resources
Before attempting these MCQs, review the Respiratory System theory notes for GNM 1st Year.
You can also revise the Important Questions on Respiratory System for GNM 1st Year before testing yourself.