As you progress down the respiratory tract from trachea to a

As you progress down the respiratory tract from trachea to alveoli, the following changes are noted _____.

Solution

The answer would be first option- Decreasing hyline cartilage, increasing smooth muscle, decreasing height of the epithelial cells.

The most distinctive features of trachea are hyaline cartilage that provides the rigidity. Epithelial height and thickness of lamina propria progressively decrease proximally to distally so as to allow the diffusion of gases to takes place easily. The amount of cartilage decreases from proximally to distally from trachea to alveoli while relative abundace of smooth muscles increases.