Bronchiole Histology in Gas Exchange System

Steps:

• Identify inner lining as pseudostratified ciliated columnar epithelium with goblet cells for mucus and clearance.
• Note underlying elastic fibers in lamina propria for recoil and flexibility.
• Confirm no cartilage present, distinguishing from larger bronchi.
• Match to transverse section features: ciliated layer atop elastic support.

Why C is correct:

• Bronchioles feature ciliated epithelial and goblet cells overlying elastic fibers, per respiratory histology definitions, enabling efficient airflow without rigid support.

Why the others are wrong:

• A: Includes cartilage, absent in smaller airways like bronchioles.
• B: Omits ciliated and goblet cells essential for mucociliary action.
• D: Places cartilage and goblet cells outer, reversing actual inner epithelial positioning.

Final answer: C