Respiratory System Development
). In the 4th week, which way do the head, tail, and body form, and what does this result in?
cranially-->foregut/caudally-->hindgut/laterally-->midgut
Where does the lung bud form?
foregut
What is the respiratory diverticulum?
=lung bud; midline, elongated outpocketing of ventral wall of foregut endoderm
What does the endodermal bud do?
invades splanchnic mesoderm
The endoderm of the lung bud forms...
the epithelial lining and glands of airways
Splanchnic mesoderm surrounding lung bud becomes...
smooth muscle, connective tissue, and cartilage of airways
The tracheoesophageal septum forms as a result of ? between cells of ? and ? in the ?
apoptosis; respiratory diverticulum; foregut; tracheoesophageal ridges
What does the respiratory diverticulum become?
trachea
What does the foregut become?
esophagus
Tracheoesophageal fistula with esophageal atresia: meanings, prevalence, accompanying issue
fistula=abnormal communication; atresia=abnormal passageway; 1/3000 births; polyhydramnios
Lung maturation: 5-16 weeks
pseudoglandular phase: branching into terminal bronchioles; mucous glands at week 12
Lung maturation: 16-26 weeks
canalicular phase: finer branching of resp. bronchioles; capillary beds now assoc. with resp. epithelium; little gas exchange
Lung maturation: 26 weeks-birth
terminal sac phase: primitive alveoli; type II alveolar cells produce surfactant; blood-air barrier est.
Lung maturation: birth-~8 years
alveolar phase: more bronchioles, alveolar ducts, terminal sacs, and alveoli; Type I alveolar cells become thin
What happens when Type I alveolar cells get thinner?
epithelial/endothelial contact with capillaries occurs