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 5 of 8
- A. A
- B. B
- C. C
- D. D
Explanation: During exhalation in humans, the diaphragm relaxes, causing it to move upwards into the thoracic cavity.
Correct answer: D- A. Pelvis
- B. Hilum
- C. Mediastinum
- D. Fissure
Explanation: The hilum of the lung is found on the medial aspect of each lung, and it is the only site of entrance or exit of structures associated…
Correct answer: Hilum- A. Glottis
- B. Bronchus
- C. Larynx
- D. Trachea
- E. Pleura
Explanation: The vocal cords are two thin, fibrous bands located in the larynx or voice box, which is a part of the respiratory system.
Correct answer: Larynx- A. Spirobacterium
- B. Mycobacterium
- C. E.Coli
- D. Staphylococcus
- E. Pseudomonas
Explanation: Tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis, which is highly infectious and can spread through the air.
Correct answer: Mycobacterium- A. 15
- B. 19
- C. 19.6
- D. 20
- E. 25
Explanation: At sea level, hemoglobin can carry a maximum of approximately 20 ml of oxygen per 100 ml of blood.
Correct answer: 20- A. Oxyhemoglobin
- B. Plasmin
- C. Myoglobin
- D. Heme
- E. Hemoglobin
Explanation: Myoglobin is a protein found in muscle tissue that binds oxygen.
Correct answer: Myoglobin- A. 1
- B. 4
- C. 3
- D. 2
- E. 5
Explanation: Hemoglobin is a protein found in red blood cells that has four heme groups, each capable of binding to one oxygen molecule.
Correct answer: 4- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: It is a fact that bronchioles don't have cartilage, so options A and C are incorrect.
Correct answer: Option D- A. Pleura
- B. Alveoli
- C. Chest cage
- D. Diaphragm
Explanation: Diaphragm forms the floor of the chest cavity.
Correct answer: Diaphragm- A. Lung cancer
- B. Chronic Bronchitis
- C. Cystic fibrosis
- D. Emphysema
Explanation: Cystic fibrosis (CF) is a genetic (inherited) disease that causes sticky, thick mucus to build up in organs, including the lungs and the…
Correct answer: Cystic fibrosis- A. 10 to 15 times per minute
- B. 10 to 20 times per minute
- C. 80 to 120 times per minute
- D. 15 to 20 times per minute
Explanation: Correct option is D. Normal respiration rates for an adult person at rest is 15 to 20 breaths per minute.
Correct answer: 15 to 20 times per minute- A. Heart
- B. Lungs
- C. Brain
- D. Kidney
Explanation: The pleural membranes cover the lungs and have a pleural fluid in between them to lubricate the lungs and prevent damage due to friction.
Correct answer: Lungs- A. Plasma membrane
- B. Mucous membrane
- C. Meninges
- D. Epithelial membrane
Explanation: The medial surface has a mucosal lining that forms the lateral aspect of the respiratory part of the glottis.
Correct answer: Mucous membrane- A. Breathing
- B. Respiration
- C. Diffusion
- D. Osmosis
Explanation: The process through which animals take oxygen (O2) from the air and release carbon dioxide (CO2) into the air is called "Breathing".
Correct answer: Breathing- A. Voice Production
- B. Energy Production
- C. Glucose Production
- D. Air Production
Explanation: The primary function of the vocal cords is to help in voice production.
Correct answer: Voice Production- A. The diaphragm contracts, expanding the thoracic cavity
- B. Passive transport of air occurs
- C. Air expands inside the lungs
- D. Air is pushed into the lungs
Explanation: The correct answer is that the diaphragm contracts, expanding the thoracic cavity.
Correct answer: The diaphragm contracts, expanding the thoracic cavity- A. Protein and disaccharide
- B. Protein and lipid
- C. Lipid and carbohydrate
- D. Carbohydrate and vitamins
Explanation: Surfactant is an agent that decreases the surface tension between two media.
Correct answer: Protein and lipid- A. Emphysema
- B. Asthma
- C. Pneumonia
- D. Bronchitis
Explanation: Emphysema destroys alveolar walls, reducing the surface area and causing permanent lung tissue loss.
Correct answer: Emphysema- A. Epiglottis
- B. Trachea
- C. Bronchi
- D. None of these
Explanation: The correct answer is Option B: Trachea. The trachea is supported by C-shaped cartilaginous rings that prevent its collapse and allow it…
Correct answer: Trachea- A. Bronchi
- B. Mucous
- C. Pharynx duct
- D. Glottis
Explanation: When you inhale, the air is first conditioned in the nasal cavity so it reaches the lungs at an appropriate temperature and humidity and…
Correct answer: Mucous