Template:Lung stage table
From Embryology
| Stage | Human | Features | ||
|---|---|---|---|---|
| Embryonic | week 4 to 5 | lung buds originate as an outgrowth from the ventral wall of the foregut where lobar division occurs | ||
| Pseudoglandular | week 5 to 17 | conducting epithelial tubes surrounded by thick mesenchyme are formed, extensive airway branching | ||
| Canalicular | week 16 to 25 | bronchioles are produced, increasing number of capillaries in close contact with cuboidal epithelium and the beginning of alveolar epithelium development | ||
| Saccular | week 24 to 40 | alveolar ducts and air sacs are developed | ||
| Alveolar | late fetal to 8 years | secondary septation occurs, marked increase of the number and size of capillaries and alveoli | ||
| Links: Species Stage Comparison | respiratory | ||||
