What structural feature connects the smooth muscle layer to the epithelium in the bronchioles?

• A. Basement membrane
• B. Lamina propria
• C. Submucosa
• D. Cartilage rings

Answer: (B)

The connection between the smooth muscle layer and the epithelium in the bronchioles is primarily facilitated by the lamina propria. The lamina propria is a layer of connective tissue that underlies the epithelium and serves multiple functions, including supporting the epithelial layer while allowing for flexibility and movement. This connective tissue layer is rich in blood vessels and is crucial for providing nutrients to the epithelium and facilitating gas exchange.

While the other structures listed play important roles in the overall anatomy of the bronchioles, they do not specifically connect the smooth muscle to the epithelium. The basement membrane, for example, provides a foundation for the epithelium, but it does not ensure a direct structural connection to the smooth muscle surrounding the bronchioles. The submucosa is a layer located deeper within the airway structure, housing larger blood vessels and glands, and does not play a direct role in the connection between smooth muscle and epithelium. Cartilage rings are significant in tracheal stability, but they are not present in the bronchioles, where the structural focus shifts to smooth muscle and elastic fibers to facilitate bronchodilation and bronchoconstriction. Thus, the lamina propria is essential