lung development

Question 1

embryonic phase: 0-7 weeks

Answer 1

lobar airways (lung buds, main bronchi)

Question 2

pseudoglandular: 5-17 weeks

Answer 2

pre-acinar airways complete (conducting airways, bronchi and bronchioli)

Question 3

canalicular: 16-27 weeks

Answer 3

respiratory airways, blood gas barrier

Question 4

saccular/alveolar: 28-40 weeks

Answer 4

alveoli appear, multiplying and enlarging in size with chest cavity

Question 5

early foetal life

Answer 5

majority of complex airway and circulatory system grown; 1/3-1/2 adult alveolar present at birth, and most by 3 y/o

Question 6

inhibitory growth factors

Answer 6

TGFB affecting matrix synthesis; retinoic acic inhibiting branching

Question 7

lung growth abnormalities: angenesis, aplasia, hypoplasia, lack of growth

Answer 7

agenesis (rare; complete absence of lung and vessel); aplasia (blind ending bronchus, no lung or vessel); hypoplasia (bronchus and rudimentary lungs present, but reduced in size or number due to lack of space caused by intra/extrathoracic such as hernia, cardiac mass), lack of growth (CTM)