Lung Development Flashcards
What are the 4 phases?
Embryonic 7 weeks
Pseudoglandular 17 weeks
Canalicular 27 weeks
Alveolar 28 weeks
When does the blood gas barrier form?
Canalicular phase
What happens in the pseudoglandular phase?
Pre acinar airways are all present
Start developing cartilage, smooth muscle and glands
What growth factors induce or inhibit lung development?
FGF = branching EGF = epithelial proliferation
Inhibitory
TGFbeta = surfactant and inhibit proliferation of epithelial
Retinoids acid = inhibit branching
What is VEGF?
Stimulator hormone
Produced by epithelial cells on the tip of the lung bud and stimulates proliferation
What happens in the canalicular ohase?
Air spaces start to enlarge
Thinning of epithelial to for blood barrier
Epithelial differentiate into type 1 and 2
When do babies become viable?
24 weeks
How to alveolar walls form?
Saccule wall =epithelium on both sides, double capillary network
Secondary septa develops led my elastin
Capillaries join to for one thin sheet
Elastin and muscle still at tip
How much of the adult alveoli should you have at term?
Third
How does blood flow increase after birth?
Expanding alveoli dilates artsier s
Vasodilators released
Inhibition of vasoconstriction
DECREASE IN PULMONARY RESISTANCE AND 10 X INCREASE IN BLOOD FLOW
What is primary ciliary dyskinesia?
Cilia do not waft and do not clear mucus
As thy have no hooks
What problems can you get with bronchial cartilages?
Incomplete cartilage rings
Irregular plates
Can get a complete ring = narrows
Malaria = softening of cartilage = obstructs airways
What lung growth anomalies can occur?
Agenesis
Aplaisa = bronchus but no lung
Hypoplasia = everything is smaller
What causes hypoplasia?
Lack of space for growth
Due to hernia, oligohydraminos
What causes cystic pulmonary airway malformation?
Defect in pulmonary mesenchyma
Normally blood supply
