Free Human Respiratory System MCQs with Answers
146 Human Respiratory System MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The human respiratory system conducts air to the alveoli, where oxygen and carbon dioxide exchange occurs across thin respiratory surfaces. Questions cover the nasal passage, trachea, bronchi, lungs, diaphragm and intercostal muscles, ventilation mechanics and gas transport, while distinguishing breathing and gaseous exchange from cellular respiration.
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146 questions · page 6 of 8
- A. 3.5 litres
- B. 2.5 litres
- C. 5-6 litres
- D. 10 litres
Explanation: When the lungs are fully inflated, the total lung capacity in liters for an average adult human is around 5-6 liters.
Correct answer: 5-6 litres- A. Pharynx
- B. Diaphragm
- C. Bronchi
- D. None of these options are correct
Explanation: The diaphragm is a thin dome-shaped muscle that separates the thoracic cavity (lungs and heart) from the abdominal cavity (intestines…
Correct answer: Diaphragm- A. 3.5 Liters
- B. 0.5 Liters
- C. 5.0 Liters
- D. 1.5 Liters
Explanation: Residual volume is the amount of air that always remains inside the lungs even after a person has forcefully exhaled as much air as…
Correct answer: 1.5 Liters- A. Tracheal cells
- B. Goblet cells
- C. Surfactant cells
- D. Pleural cells
Explanation: The primary function of goblet cells is to synthesize and secrete mucus.All the other type of cells mentioned are part of respiratory…
Correct answer: Goblet cells- A. Relaxes and domes up
- B. Contracts and flattens
- C. Remains unchanged
- D. Contracts and domes up
Explanation: During inspiration, the diaphragm contracts and flattens, increasing thoracic volume and drawing air in.
Correct answer: Contracts and flattens- A. Globin
- B. Myoglobin
- C. Myoglycogen
- D. Glycogen
Explanation: Myoglobin is found in skeletal muscles consisting of one polypeptide chain with each molecule containing one iron-containing haem group.
Correct answer: Myoglobin- A. Smooth muscle cells
- B. Goblet cells
- C. Alveoli
- D. Epithelial cells
- E. Pleural cells
Explanation: Explanation for this question will be added soon.
Correct answer: Goblet cells- A. Internal intercostal muscles contract
- B. External intercostal muscles relax
- C. Diaphragm relaxes
- D. Occurs due to increased pressure in thoracic cavity
- E. External intercostal muscles contract
Explanation: Explanation for this question will be added soon.
Correct answer: External intercostal muscles contract- A. Larynx
- B. Trachea
- C. Bronchioles
- D. Bronchi
Explanation: Terminal Bronchioles is the last part of the conducting portion of the respiratory system, and has the smallest diameter of all (less than…
Correct answer: Bronchioles- A. 6 to 10 times per minute
- B. 10 to 14 times per minute
- C. 12 to 16 times per minute
- D. 15 to 20 times per minute
Explanation: Normal breathing rates for an adult person at rest range from 12 to 16 breaths per minute.
Correct answer: 12 to 16 times per minute- A. Chemical process
- B. Biochemical process
- C. Mechanical process
- D. Both Option B and C are correct
Explanation: Respiration is both mechanical and biochemical process
Correct answer: Both Option B and C are correct- A. Carboxyhemoglobin
- B. Plasma proteins
- C. Bicarbonate ions
- D. In dissolved form
Explanation: 70% of carbon dioxide is transported in the blood as bicarbonate ions, 23% as carboxyhemoglobin and 7% in water of plasma.
Correct answer: Bicarbonate ions- A. Glottis
- B. Voice box
- C. Epiglottis
- D. Vocal cords
Explanation: The voice box or larynx is located at the upper end of the trachea. It is a hollow chamber with cartilaginous walls and contains a pair of…
Correct answer: Voice box- A. Emphysema
- B. Asthma
- C. Pneumonia
- D. Bronchitis
Explanation: Pneumonia is a disease of the upper respiratory tract in which Chills, sputum production and fever is observed.
Correct answer: Pneumonia- A. Bronchi
- B. Bronchioles
- C. Windpipe
- D. Larynx
Explanation: Air from pharynx passes to larynx, which is called voice box.
Correct answer: Larynx- A. Glottis
- B. Epiglottis
- C. Larynx
- D. Vocal cords
Explanation: Epiglottis guards the opening of the larynx and it is flap-like in shape.
Correct answer: Epiglottis- A. 3.5 litres
- B. 2.5 litres
- C. 5.5 litres
- D. 8 litres
Explanation: The total lung capacity means the maximum amount of gas that a lung can hold. It is approximately 5-6 liters.
Correct answer: 5.5 litres- A. Lungs pull air inside
- B. Passive transport of air takes place
- C. Passive expansion of air takes place
- D. Air is pushed inside
Explanation: Lungs pull air inside: This option is correct. During inspiration, the expansion of the thoracic cavity occurs passively due to the…
Correct answer: Lungs pull air inside- A. 5 ml
- B. 50 ml
- C. 500 ml
- D. 5000 ml
Explanation: The total lung capacity is approximately 5 L. Of this, 1.5 L, the residual volume, remains at the end of forced expiration.
Correct answer: 5000 ml- A. Bicarbonate
- B. COz
- C. Carboxyhemoglobin
- D. Blood plasma protein
Explanation: Explanation:The majority of carbon dioxide molecules are carried as part of the bicarbonate buffer system.This option is not correct.
Correct answer: Bicarbonate