Flashcards in Embryology of the Lungs Deck (21):
What process separates the trachea from the esophagus?
Failed sepatation -> tracheo-esophageal fistulae.
What do primary, secondary, and tertiary buds correspond to in the adult lung?
Primary: 2 main bronchi.
Secondary: 2 left lobes, 3 right lobes.
Tertiary: 8(ish) left segments, 10 right segments.
Terminal bronchioles form... and then terminal sacs form.
Okay... that's a sensible order for that to happen in.
4 periods of lung development? (... the slides start at period II)
What gestational age range does each happen in?
II: Pseudoglandular Period, 6-16 wks, terminal bronchioles.
III: Canalicular Period, 16-26 wks, 1st terminal sacs (first possibility of gas exchange).
IV: Terminal Sac Period, 26 wks -birth, Type I and II epithileal cells.
V: Alveolar period, 32 wks - 8 years, more alveoli and surfactant.
What do Type II epithelial cells do?
Serve as stem cells.
What does "maturation" of terminal sacs into alveoli entail?
Type I epithelial cells thin to allow better gas exchange.
What tells the growing conducting ducts to branch?
The mesenchyme.... it tells the ducts what level they're at and how much they should branch.
What's a signaling molecule particularly found in distal mesenchyme that tells ducts to act distal-ish?
In branching... what grows, and what doesn't grow?
Tips grow (highly mitotic).
Spaces between tips/buds have growth inhibitors present. (such as Sprouty)
What might specifically inducing branching at the tip of a growing bud?
Sonic hedgehog (Shh) inhibits FGF10.
How are distal and proximal duct epithelial cell morphologies distinct?
Proximal - ciliated, psuedostratified guys.
Distal: Type I and Type II epithelial cells.
(this involves Wnt, BMP, and Gremlin, but that's almost too silly to talk about)
Okay, but if we really want to talk about Wnt, BMP, and Gremlin, what do they do with regards to lung epithelium morphology?
WNT and BMP induce distal epithelial.
Gremlin inhibits distal epithelial differentiation.
(if you don't have WNT... you have more ciliated epithelium)
Cardiopulmonary progenitors mediate connection between lung and heart.
What causes respiratory distress syndrome RDS?
What does the other lung do when there's 1 lung that just doesn't form at all?
it grows to be bigger.
Congenital diaphragmatic hernia. Why it bad for the lungs?
If smooshed, the lungs don't fully develop.
What's a bronchogenic cyst?
Lung tissue where it's not supposed to be - budding off some other part of the gut tube.
What's Congenital Cystic Adenomatoid Malformation (CCAM)?
CCAMs are from messed up branching... too many terminal bronchioles with too few alveoli... or something.
A mouse model with too much FGF10 resembles CCAM.
Mutation in what non-surfactin protein will cause the same phenotype as mutations in surfactin B and surfactin C.
The ATP-dependent transporter, ABCA3.
(because ABCA3 transports those proteins... in some important step0
What disease might result from the reactivation of things like BMP, Wnt, TGFbeta, and Gremlin?
Idiopathic Pulmonary Fibrosis