The rings of cartilage in the wall of the trachea are C shaped rather than complete because
Correct answer: D. the incomplete side lies against the oesophagus and lets it expand during swallowing
- A. complete rings would restrict the flow of air
- B. cartilage is too expensive for the body to make
- C. the gap allows nerves to reach the lung
- D. the incomplete side lies against the oesophagus and lets it expand during swallowing
Explanation
The cartilage keeps the airway permanently open so it cannot collapse when pressure falls during inspiration, while the soft muscular gap at the back allows a swallowed bolus to bulge into the space as it passes down the oesophagus behind. Complete rings would give the same support but would obstruct swallowing. The rings do not restrict airflow in any way.
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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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