Epithelium	Epithelial cells	Mucous cells	Glands	Cartilage	Elastic fibers	Smooth muscle
trachea	pseudostratified	ciliated, mucous,* & basal*	present	seromucous +++++	C-shaped rings	present	spans open ends of C-shaped rings
large bronchi	"	"	present	seromucous +++	irregular rings	abundant	spiral bundles encircling mucosa /submucosa
small bronchi	"	"	present	seromucous +	plates & islands	"	spiraling bundles
bronchiole	transition to simple columnar	ciliated & Clara*	few-to- none	none	none	"	wide-spread spiral bundles
respiratory bronchiole	simple columnar & alveoli	as above, + type I & II*	none	none	none	+	sparser bundles
alveolar duct	alveoli & simple columnar	type I & type II*	none	none	none	+	minimal bundles with sphincter at end
alveolar sac	simple alveolar epithelium	"	none	none	none	+	none
alveolus	simple alveolar epithelium	+	none	none	none	+	none

* denotes a cycling cell

Go to:
[Front page||Main Index|Anatomical Figure|Schematic/Chart|Thumbnail|Slide Number|Keyword]