Free Respiration MCQs with Answers

• A. Malaria
• B. Lung cancer
• C. Emphysema
• D. Chronic bronchitis

Explanation: Malaria is transmitted by the Anopheles mosquito and has nothing to do with tobacco.

• A. a higher than average birth weight
• B. a low birth weight
• C. extra ribs
• D. immunity against respiratory infection

Explanation: Carbon monoxide and nicotine reduce the oxygen and blood supply to the fetus, restricting growth and raising the risk of premature birth.

• A. improved filtering of dust
• B. faster removal of mucus
• C. accumulation of mucus and debris, producing the smoker's cough
• D. widening of the trachea

Explanation: Healthy cilia sweep mucus and trapped particles upwards, and when smoke paralyses them the debris collects instead.

• A. tobacco is inexpensive
• B. cigarettes contain essential vitamins
• C. withdrawal produces no symptoms
• D. nicotine produces strong physical and psychological dependence

Explanation: Nicotine reaches the brain within seconds and alters reward pathways, so stopping brings cravings and withdrawal.

• A. the brand of cigarette
• B. the time of day the cigarettes are smoked
• C. the length of the filter
• D. the number of cigarettes per day and the number of years of smoking

Explanation: Cancer risk follows cumulative dose: each cigarette adds exposure to carcinogens over years of tissue damage.

• A. emphysema
• B. asthma
• C. pneumonia
• D. bronchitis

Explanation: The merged, ragged air spaces of emphysema cannot transfer enough oxygen, leaving the patient breathless even at rest.

• A. It is safer than cigarettes because the smoke passes through water
• B. It also delivers nicotine, tar and carbon monoxide and is harmful
• C. It contains no tobacco at all
• D. It affects only the mouth

Explanation: The water cools the smoke but removes little tar or CO, and sessions are long, so intake is substantial.

• A. treating lung cancer at an earlier stage
• B. giving antibiotics to all smokers
• C. preventing people from starting and supporting smokers to quit
• D. switching smokers to cigars

Explanation: Emphysema and cancer are largely irreversible once established, so prevention and cessation save far more lives than treatment of late…

• A. Bronchi
• B. Bronchioles
• C. Alveoli
• D. Trachea

Explanation: Alveoli are the site of gas exchange, with thin walls and large surface area for efficient O2 and CO2 diffusion.

• A. Type I alveolar cells
• B. Type II alveolar cells
• C. Goblet cells
• D. Ciliated cells

Explanation: Type II pneumocytes (alveolar cells) produce surfactant, which reduces surface tension to prevent alveolar collapse.

• A. O2 binding to hemoglobin
• B. Effect of CO2/pH on O2 affinity
• C. CO2 transport
• D. Lung compliance

Explanation: The Bohr effect states that increased CO2/decreased pH reduces hemoglobin's affinity for O2, facilitating O2 release to tissues.

• A. Dissolved in plasma
• B. Carbaminohemoglobin
• C. Bicarbonate ions
• D. Free CO2

Explanation: About 70% of CO2 is transported as bicarbonate (HCO3-) in plasma, formed by carbonic anhydrase in RBCs.

• A. 500 mL
• B. 3000 mL
• C. 1200 mL
• D. 6000 mL

Explanation: Tidal volume (air in normal breath) is about 500 mL at rest in healthy adults.

• A. Cerebrum
• B. Cerebellum
• C. Medulla oblongata
• D. Hypothalamus

Explanation: The respiratory center in the medulla oblongata controls breathing rate and depth.

• A. pH is low
• B. CO2 is high
• C. pH is high
• D. Temperature is high

Explanation: Hemoglobin has highest O2 affinity at high pH, low CO2, and low temperature (in the lungs).

• A. Maintain electrical neutrality
• B. Increase O2 transport
• C. Decrease CO2
• D. Activate enzymes

Explanation: As HCO3- leaves RBCs, Cl- enters to maintain electrical neutrality (chloride shift or Hamburger shift).

• A. Emphysema
• B. Bronchoconstriction and inflammation
• C. Lung cancer
• D. Pneumonia

Explanation: Asthma involves bronchoconstriction, airway inflammation, and excess mucus production, causing wheezing and dyspnea.

• A. Humidifying air
• B. Filtering dust
• C. Gaseous exchange
• D. Voice production

Explanation: The larynx houses the vocal cords, and air forced between them makes them vibrate to produce sound, which is why it is called the voice…

• A. Cancer causing
• B. Pneumonia causing
• C. Emphysema
• D. Asthma

Explanation: Carcinogens are chemical or physical agents that can cause cancer by damaging DNA or disturbing the control of cell division.

• A. Carbon monoxide
• B. Methene
• C. Oxygen
• D. Nitrogen dioxide

Explanation: Carbon monoxide binds haemoglobin to form carboxyhaemoglobin, with an affinity about 200 to 250 times greater than oxygen, reducing oxygen…