What feature prevents the trachea from collapsing during breathing?

• A. Elastic tissue
• B. Cartilage rings
• C. Cilia
• D. Smooth muscle

Answer: (B)

Cartilage rings provide the key structural support that keeps the airway open. The trachea is reinforced by C-shaped rings of hyaline cartilage that form a rigid framework around the tube, preventing it from collapsing as air moves in and out and as the chest expands during breathing. The open part of the ring faces the back, where the posterior wall is flexible due to smooth muscle and connective tissue, allowing room for swallowing and some movement without compromising patency. Cilia and mucus transport lining the trachea, but they don’t keep the airway open. Elastic tissue or smooth muscle contribute to flexibility and diameter regulation, but they don’t provide the rigid, constant support needed to prevent collapse.