MDCAT Biology Quiz 13 – RESPIRATION Leave a Comment / By studentseoasis.org / July 24, 2025 1. Primary function of the human respiratory system is: A) Pump blood B) Produce hormones C) Exchange gases D) Digest food None 2. Air enters the respiratory system through: A) Trachea B) Nasal cavity C) Alveoli D) Bronchioles None 3. The windpipe is also known as: A) Bronchi B) Alveoli C) Trachea D) Pharynx None 4. Larynx is commonly called the: A) Windpipe B) Voice box C) Throat D) Food pipe None 5. The function of epiglottis is to: A) Produce sound B) Moisten air C) Prevent food entering trachea D) Trap dust particles None 6. Bronchi are: A) Tiny air sacs B) Branches of trachea entering lungs C) Air-filtering hairs D) Respiratory muscles None 7. Bronchi divide further into: A) Alveoli B) Pharynx C) Bronchioles D) Trachea None 8. Alveoli are the site of: A) Air filtration B) Sound production C) Gas exchange D) Food digestion None 9. Lungs are protected by: A) Skull B) Ribs C) Pelvis D) Vertebral column None 10. Which muscles help in breathing? A) Abdominal muscles B) Diaphragm and intercostal muscles C) Shoulder muscles D) Neck muscles None 11. During inhalation, the diaphragm: A) Contracts and moves downward B) Relaxes and moves upward C) Contracts and moves upward D) Expands laterally None 12. The function of nasal hairs and mucus is to: A) Produce oxygen B) Trap dust and microbes C) Enhance gas exchange D) Moisten alveoli None 13. Vocal cords are found in: A) Pharynx B) Larynx C) Bronchi D) Alveoli None 14. Which part humidifies and warms incoming air? A) Trachea B) Nasal cavity C) Alveoli D) Larynx None 15. Which structure prevents food from entering respiratory tract? A) Pharynx B) Larynx C) Epiglottis D) Bronchi None 16. Air moves from bronchioles into: A) Bronchi B) Alveoli C) Trachea D) Pharynx None 17. Oxygen enters blood in: A) Bronchi B) Alveoli C) Trachea D) Bronchioles None 18. Which organ is the main site of respiration? A) Brain B) Heart C) Lungs D) Liver None 19. What structure filters large particles from inhaled air? A) Alveoli B) Vocal cords C) Nasal cavity D) Lungs None 20. During exhalation, the diaphragm: A) Contracts B) Relaxes C) Moves downward D) Increases thoracic volume None 21. Gas exchange occurs in: A) Trachea B) Bronchi C) Alveoli D) Larynx None 22. Oxygen diffuses from alveoli into: A) Lymph vessels B) Red blood cells C) Bronchioles D) Bronchi None 23. Which gas diffuses from blood to alveoli? A) Oxygen B) Nitrogen C) Carbon dioxide D) Helium None 24. Gas exchange in lungs occurs by: A) Active transport B) Diffusion C) Osmosis D) Endocytosis None 25. Capillaries surrounding alveoli help in: A) Producing mucus B) Transporting sound C) Gas exchange D) Moistening air None 26. Partial pressure difference drives: A) Muscle contraction B) Blood circulation C) Gas diffusion D) Voice production None 27. Oxygen binds to: A) Plasma B) Hemoglobin in RBCs C) White blood cells D) Platelets None 28. In alveoli, oxygen concentration is: A) Lower than blood B) Equal to blood C) Higher than blood D) Same as in tissues None 29. What surrounds alveoli? A) Large arteries B) Veins C) Capillary networks D) Lymph nodes None 30. Blood rich in oxygen leaves lungs via: A) Pulmonary artery B) Pulmonary vein C) Bronchial vein D) Trachea None 31. CO₂ is transported from tissues to lungs mainly as: A) Dissolved in plasma B) Attached to hemoglobin C) Bicarbonate ions D) Oxygenated plasma None 32. Exchange of gases in lungs is called: A) Internal respiration B) Cellular respiration C) External respiration D) Ventilation None 33. The large surface area for gas exchange is provided by: A) Trachea B) Bronchi C) Alveoli D) Lymph nodes None 34. Pulmonary capillaries carry: A) Oxygenated blood to alveoli B) Deoxygenated blood to alveoli C) Nutrients to lungs D) Hormones to alveoli None 35. During inhalation, air pressure inside lungs becomes: A) Higher than outside B) Lower than outside C) Equal to outside D) Zero None 36. Alveolar walls are: A) Thick B) Multi-layered C) One cell thick D) Composed of cartilage None 37. Gas exchange efficiency depends on: A) Diaphragm strength B) Alveolar wall thickness C) Number of bronchi D) Mucus production None 38. Haemoglobin carries: A) Only oxygen B) Only carbon dioxide C) Both oxygen and carbon dioxide D) Nitrogen only None 39. Carbon dioxide is removed from blood at: A) Trachea B) Alveoli C) Pharynx D) Larynx None 40. The alveoli provide: A) Small surface area B) Large surface area C) Low diffusion rate D) Thick exchange barrier None 41. Smoking reduces: A) Hemoglobin levels B) Lung capacity C) Oxygen need D) Number of red blood cells None 42. The harmful gas in cigarette smoke is: A) Oxygen B) Nitrogen C) Carbon monoxide D) Hydrogen None 43. Carbon monoxide binds to hemoglobin more readily than: A) Oxygen B) Carbon dioxide C) Nitrogen D) Plasma None 44. Smoking damages: A) Alveoli only B) Diaphragm C) Cilia lining respiratory tract D) Cartilage rings None 45. Smoking increases the risk of: A) Anemia B) Diabetes C) Lung cancer D) Bone fracture None 46. Which disease is commonly caused by smoking? A) Asthma B) Tuberculosis C) Chronic bronchitis D) All of the above None 47. Tar in cigarettes: A) Cleans alveoli B) Strengthens bronchioles C) Coats alveoli, reducing gas exchange D) Reduces heart rate None 48. Cigarette smoke paralyzes: A) Rib muscles B) Diaphragm C) Mucus glands D) Cilia in airways None 49. Long-term smoking may lead to: A) Increased lung elasticity B) Emphysema C) Better gas exchange D) Enhanced immunity None 50. Passive smoking is harmful because: A) It strengthens lungs B) It reduces mucus C) Secondhand smoke contains toxins D) It provides oxygen None 1 out of 50 Time's up
