An asthma attack, in which breathing becomes difficult with wheezing, is caused by
Correct answer: B. constriction of the bronchi and bronchioles with excess mucus
- A. fluid filling the alveoli
- B. constriction of the bronchi and bronchioles with excess mucus
- C. destruction of the cartilage rings of the trachea
- D. paralysis of the diaphragm
Explanation
The airway smooth muscle contracts and the lining swells with mucus, narrowing the tubes so air whistles through. Inhalers relax the muscle, confirming that constriction, not destruction, is the problem.
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About Human Respiratory System
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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