Parameter | Human | Monkey | Mouse |
Wall | |||
Smooth muscle | Present | Present | Present |
Cartilage | Present | Present | Absent |
Submucosal glands | Present | Present | Absent |
Epithelium | |||
Thickness μm | 40–50 | 27 | 8–16 |
Cells per mm basement membrane | NA | 175 | 109 |
Mucous goblet cells % | 10 | 15 | <1 |
Serous cells % | 3 | 5 | <1 |
Clara cells % | 61 | ||
Ciliated cells % | 37 | 47 | 36 |
Basal cells % | 32 | 32 | <1 |
Other % | 18 | 2 | 2 |