Bronchi/lungs
_By 28 days
– endodermal buds grow along with splanchnic mesenchyme
_By 35 days – Second degree bronchi, upper middle and lower on right, upper and lower on left
_By 42 days – Tertiary bronchopulmonary segments, 10 on the right and 8-9 on the left.
_By 35 days – Second degree bronchi, upper middle and lower on right, upper and lower on left
_By 42 days – Tertiary bronchopulmonary segments, 10 on the right and 8-9 on the left.