From: Apolipoprotein C-II and lipoprotein lipase show a temporal and geographic correlation with surfactant lipid synthesis in preparation for birth
GD 15.5
GD 17.5
GD 18.5
GD 19.5
PN 0
PN 5
Mesenchyme
CII & LPL
Distal epithelium
Respiratory bronchioles
Septa
Macrophages