Page 684 - Atlas of Histology with Functional Correlations

tissue septa by their phagocytosed particulate or carbon particles.

Summary

Respiratory System

Components of Respiratory System—

Overview

Conducting portion consists of solid passageways that move air in and out of
lungs

Extrapulmonary passages include the trachea and bronchi
Pseudostratified ciliated epithelium with numerous goblet cells lines the
larger passageways
As passageways branch and enter lung, there is a decrease in epithelium

height and tubule size
Terminal bronchioles represent the terminal portion of conducting portion
Respiratory bronchioles represent the transition zone between conducting and
respiratory zones

Respiratory Epithelium

Ciliated cells are most common and extend the thickness of epithelium and

sweep the surface
Goblet cells are numerous in airways, secrete protective mucus, but decrease
in distal parts

Basal cells are close to basal lamina, do not reach the surface, and serve as
stem cells
Brush cells are less numerous, contact afferent axons, and may function as
receptors cells
Small granule cells contain granules and are analogous to enteroendocrine

cells (DNES)

683