Embryology

Question 1

Which germ layer gives rise to the lung bud and the lining of the respiratory tree?

Answer 1

Endoderm

Question 2

Which germ layer gives rise to the smooth muscle, cartilage and blood supply of the respiratory tree?

Answer 2

Mesoderm

Question 3

How do primary bronchial buds form?

Answer 3

Bifurcation of the trachea, producing the right and left bronchi

Question 4

How do secondary bronchial buds form?

Answer 4

Bifurcation of right + left bronchi, producing 3 right lobar bronchi and 2 left lobar bronchi

Question 5

Name the 5 stages of lung development (elephants play chess in sunny Africa…)

Answer 5

Embryonic
Pseudoglandular
Canalicular
Saccular
Alveolar

Question 6

What happens in the embryonic phase of lung maturation?

Answer 6

Respiratory diverticulum forms off oesophagus

Initial branching produces lung, lobes + segments

Question 7

What happens in the pseudoglandular phase of lung maturation?

Answer 7

Terminal bronchioles form

Question 8

What happens in the canalicular phase of lung maturation?

Answer 8

Respiratory bronchioles form

Question 9

What happens in the saccular phase of lung maturation?

Answer 9

Terminal sacs form (begin to form alveoli)

Question 10

What happens in the alveolar phase of lung maturation?

Answer 10

Alveolar sacs mature