The Trachea
Identification:
The trachea slides can be identified at both lower power (first slide) or high power (second slide) by the distinctive purple-staining hyaline cartilage (1). At low power these form C-shaped rings (it appears as smaller segments in the first slide because it is an oblique section through the trachea and segments from several rings are seen).
Features to know:
Hyaline cartilage (1)
Pseudostratified ciliated columnar epithelium (2) lining the inside of the trachea
Gobet cells within the epithelium (5)
Trachealis muscle "closes" the C-shapred rings of cartilage, but is not very clear in the low power slide. Its approximate location is indicated by (3)
Other features:
The circular structures (4) are mucus glands.
The Lung
Identification:
The lung slides can be identified by the thin layers of cells (simple squamous) arranged to form large, empty sacs (alveoli).
Features to know:
Alveoli are the individual sacs
Simple squamous epithelium surrounds each alveolus and consists of Type I and Type II cells
Type I cells (1) are squamous (flattened), have an oval nucleus and function in gas exchange
Type II cells (2) are cuboidal (squarish), have a round nucleus and produce surfactant
