1. BIO 241 HISTOLOGY REVIEW Respiratory System
Dr. Tim Ballard
Department of Biology and Marine Biology

2. Trachea
Trachea –section – H&E – 4x objective
C-shaped ring of hyaline cartilage
submucosa
lumen
esophagus
ciliated pseudostratified columnar epithelium
The arrowhead indicates the trachealis muscle, which bridges the open ends of the C-shaped cartilage ring.

3. ciliated pseudostratified columnar epithelium
Trachea
Trachea –section – H&E – 10x objective
ciliated pseudostratified columnar epithelium
adventitia
submucosa
lumen
hyaline cartilage
adipose tissue

4. Trachea
Trachea –section – H&E – 40x objective
cilia
ciliated pseudostratified columnar epithelium
submucosa
hyaline cartilage
Although not shown in this view, goblet cells should be seen easily scattered throughout the epithelial layer.

5. Intrapulmonary bronchus
Intrapulmonary bronchus – cross section – H&E – 10x objective
ciliated pseudostratified columnar epithelium
lumen
alveoli
The arrow shows a plate of cartilage, not a C-shaped ring. This is a diagnostic feature of this type of bronchus. Very little smooth muscle is present.

6. Bronchiole
Bronchiole – cross section – H&E – 4x objective
The arrow shows a bronchiole. Note that there are no plates of cartilage around it. The arrowhead points out a branch of the pulmonary artery.

7. Bronchiole
Bronchiole – cross section – H&E – 10x objective
smooth muscle
The star shows a bronchiole. Note that there are no plates of cartilage around it.

8. ciliated simple columnar epithelium
Bronchiole
Bronchiole – cross section – H&E – 40x objective
ciliated simple columnar epithelium
Note the change in the epithelium to a short columnar/cuboidal with no goblet cells. Cilia are still present.

9. Respiratory bronchiole
Respiratory bronchiole – cross section – H&E – 10x objective
respiratory bronchiole
Arrows indicate alveoli arises directly from the respiratory bronchiole. There is simple squamous epithelium and some smooth muscle. PA=pulmonary artery

10. Alveoli Respiratory bronchiole – cross section – H&E – 10x objective
alveolar wall
alveolar sac