Developmental Aspect of Lung Disease Flashcards
At what weeks of gestation does the embryonic lung development phase span?
3 - 8 weeks
What happens first during the embryonic phase?
Lung offshoots off the foregut
What germ layer does the lung grow into?
Mesoderm
What does the primary bronchial tube act as at this point?
A gland
What does the bronchial tube gland secrete into?
Amniotic fluid
At this point, how close do blood vessels lie to airways?
Far away
What stage follows the embryonic stage and how long does it last?
- Pseudo glandular - 5 - 17 weeks
What starts to form at the pseudo glandular phase?
- Very early lung
- Lobes become obvious
What starts to form in the bronchioles during the pseudoglandular phase?
Myofibrils
How much metabolic activity occurs during the pseudoglandular phase?
Lots
Describe the image relating to A) blood vessel position B) glandular aspect C) myofibrils
A) still far away from airways
B) acinar tubules widely branching
C) myofibrils forming around bronchioles
What is the next phase in lung development following the pseudoglandular and how long does it last?
- Canalicular
- 16 - 26 weeks
What is the main formation during the canalicular phase?
- Squamous epithelium forms
What does the formation of the squamous epithelium during the canalicular phase allow?
Gas exchange to be possible
What else occurs during the canalicular phase to allow gas exchange to occur?
Blood vessels move closer to the saccules
What phase follows the canalicular phase and how long does it last?
- Saccular
- 24 - 38 weeks
What occurs during the saccular phase?
More saccules form
What phase begins at 36 weeks and can last 2/3 years after birth?
Alveolar phase
What happens to the saccules during the alveolar phase?
They turn into alveoli