Transition from bronchiole to respiratory bronchiole

This passageway includes portions of a bronchiole and a terminal bronchiole.

Bronchioles are lined by a simple columnar/cuboidal epithelium with cilia and goblet cells.

Bronchioles are lined by a simple columnar/cuboidal epithelium with cilia and goblet cells.

Bronchioles are lined by a simple columnar/cuboidal epithelium with cilia and goblet cells.

Terminal bronchioles are lined by a simple cuboidal epithelium with sparse cilia and club cells. Goblet cells are not present.

Terminal bronchioles are lined by a simple cuboidal epithelium with sparse cilia and club cells. Goblet cells are not present.

Respiratory bronchioles are lined by the same epithelium as terminal bronchioles but is interrupted by the presence of alveoli in the wall.

Respiratory bronchioles are lined by the same epithelium as terminal bronchioles but is interrupted by the presence of alveoli in the wall.

Respiratory bronchioles are lined by the same epithelium as terminal bronchioles but is interrupted by the presence of alveoli in the wall.

Respiratory bronchioles are lined by the same epithelium as terminal bronchioles but is interrupted by the presence of alveoli in the wall.

Respiratory bronchioles continue as alveolar ducts, elongated passageways whose walls consist almost entirely of alveoli. The opening of each alveolus is surrounded by a ring of smooth that appears like a “knob” in cross section.

Respiratory bronchioles continue as alveolar ducts, elongated passageways whose walls consist almost entirely of alveoli. The opening of each alveolus is surrounded by a ring of smooth that appears like a “knob” in cross section.

The image was taken of a slide in the Duke University collection.