In human respiratory system, bronchioles have:
Correct answer: C. Circular smooth muscles
- A. Cartilage rings
- B. Cartilage plates
- C. Circular smooth muscles
- D. Longitudinal smooth muscles
Explanation
Bronchioles have no cartilage in their walls, which instead contain circular smooth muscle that can narrow or widen the airway, as happens in asthma. Cartilage rings support the trachea and cartilage plates the bronchi, so those options describe the larger airways.
This question appeared on the UHS MDCAT 2026 paper, which you can sit online with every answer explained.
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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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