Secondary bronchus
A secondary bronchus resembles a primary bronchus except that all layers are thinner; the passageway is surrounded by plates rather than rings of cartilage; and the smooth muscle becomes more prominent. Abundant, longitudinal elastic fibers remain in the lamina propria, but they are more dispersed than in the trachea and primary bronchi. 200x
Epithelium >
The epithelium of a secondary bronchus is pseudostratified columnar with cilia and goblet cells. The lamina propria is rich in elastic fibers, and smooth muscle bands spiral around the bronchus.
Lamina propria
The epithelium of a secondary bronchus is pseudostratified columnar with cilia and goblet cells. The lamina propria is rich in elastic fibers, and smooth muscle bands spiral around the bronchus.
- Smooth muscle
The epithelium of a secondary bronchus is pseudostratified columnar with cilia and goblet cells. The lamina propria is rich in elastic fibers, and smooth muscle bands spiral around the bronchus.
- Mixed glands >
Mixed glands are visible in the lamina propria of the secondary bronchus as well as spilling around the cartilage plates.
Cartilage plates >
Cartilage plates, rather than cartilage rings, maintain patency in a secondary bronchus.
Bronchial blood vessels >
Bronchial blood vessels lie within the wall of each secondary bronchus, supplying the tissues of the wall.
Alveoli >
Alveoli surrounding this secondary bronchus indicate that this passageway is intrapulmonary.
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