Developmental aspects of lung disease

Question 1

What are the 5 stages of respiratory morphogenesis, and when do they occur during development?

Answer 1

Embryonic - 3-8 weeks
Pseudo-glandular - 5-17
Canalicular - 16-26
Saccular - 24-38
Alveolar - 36 - 2-3 years

Question 2

What happens during the embryonic stage?

Answer 2

The appearance of lung buds, main pulmonary arteries, trachea and main bronchi

Question 3

What happens during the pseudo-glandular stage?

Answer 3

All conducting airways and accompanying blood vessels form, wall structure and epithelial cells differentiate

Question 4

What happens during the canalicular stage?

Answer 4

Respiratory airways form, blood-gas barrier thins, surfactant appears

Question 5

What happens during the saccular/alveolar stage?

Answer 5

Saccules form and then alveoli form, forming 100 million by birth

Question 6

What are examples of conditions that may be present at birth?

Answer 6

Airway stenosis
Airway Malacia
Pulmonary agenesis/hypoplasia
Tracheo-oesophogeal fistula
Bronchogenic cysts

Question 7

What are examples of congenital conditions that can begin during development?

Answer 7

Lobar emphysema
Crystadenomatoid malformation
sequestration

Question 8

What are the presenting features of respiratory conditions at different stages?

Answer 8

Abnormalities in foetal ultrasound