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Free Respiration MCQs with Answers

446 Respiration 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 includes the air passages, lungs, alveoli and breathing muscles, while gaseous exchange explains how oxygen enters blood and carbon dioxide leaves it by diffusion. The effects of smoking include damage to cilia and alveoli, reduced gas exchange, chronic bronchitis, emphysema and increased risk of lung cancer.

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Human Respiratory SystemGaseous Exchange in LungsEffects of Smoking
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446 questions · page 23 of 23

441. Percentage of CO2 carried by plasma proteins is:

  • A. 5%
  • B. 6%
  • C. 7%
  • D. 8%

Explanation: Carbon dioxide (CO2) is transported in the blood in three main forms. Approximately 7% of CO2 is transported bound to plasma proteins…

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Correct answer: 7%

442. If a new born baby possesses carboxyhemoglobin instead of the oxyhemoglobin, the condition may be:

  • A. Embolism
  • B. Atherosclensis
  • C. Cyanosis
  • D. Arteriosclerosis

Explanation: Cyanosis indicates there may be decreased oxygen attached to red blood cells in the bloodstream.

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Correct answer: Cyanosis

443. Each nasal cavity is lined with mocous membrane of:

  • A. Flagellated endothelium
  • B. Flagellated epithelium
  • C. Ciliated epithelium
  • D. All of the above

Explanation: The nasal cavity is lined with a mucous membrane that contains a specialized type of epithelium called ciliated epithelium.

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Correct answer: Ciliated epithelium

444. Presence of cartilaginous ring in respiratory tract act as:

  • A. Support
  • B. Keep passage open
  • C. Prevent collapsing
  • D. All of the above

Explanation: A. Support: The rings provide structural support to the trachea and bronchi, helping to maintain their shape and prevent collapse during…

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Correct answer: All of the above

445. The lateral walls of the chest cavity of man are composed of the:

  • A. Ribs and trachea
  • B. Intercostal muscles
  • C. Ribs & intercostal muscles
  • D. Ribs, intercostal muscles & diaphragm

Explanation: Option C, "Ribs & intercostal muscles," is the correct answer. The lateral walls of the chest cavity in humans are primarily composed of…

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Correct answer: Ribs & intercostal muscles

446. Where does the Trachea lie in relation to the esophagus?

  • A. Dorsal
  • B. Ventral
  • C. Medial
  • D. Lateral

Explanation: The trachea (windpipe) is located ventral (in front of) the esophagus in the thoracic cavity.

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Correct answer: Ventral
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