Parameter | Human | Monkey | Mouse |
Wall | |||
Smooth muscle | Present | Present | Present |
Cartilage | Present | Present | Present |
Submucosal glands | Present | Present | Present (proximal 1/3) |
Epithelium | |||
Thickness μm | 50–100 | 20–30 | 11–14 |
Cells per mm basement membrane | 303±20 | 181±51 | 215 |
Mucous goblet cells % | 9 | 17 | <1 |
Serous cells % | <1 | <1 | |
Clara cells % | <1 | 49 | |
Ciliated cells % | 49 | 33 | 39 |
Basal cells % | 33 | 42 | 10 |
Other cells % | 8 | 1 |