Epithelium and glands of
lanyggotracheal area develop from:
endoderm
Connective tissue, cartilage, and smooth muscle of laryngotracheal area develop from:
splanchnic mesoderm
EXCEPT
laryngeal cartilage from: neural crest mesenchyme
What develops from myoblasts of the 4th and 6th pharyngeal arches?
laryngeal skeletal muscle
What innervates the laryngeal skeletal muscles?
vagus nerve
superior laryngeal and recurrent laryngeal nerves
Remind me again what laryngeal cartilage is derived from?
Neural crest ectoderm
Name two negative consequences of a tracheoesophageal fistula:
1) Food or gastric contents aspirate into lungs and cause pneumonia or pneumonitis
2) Polyhydramnios occurs because amniotic fluid cannot pass into the GI tract for absorption and placental transfer
What developing structure separates the trachea from the esophagus.
HINT - very straightforward
Tracheoesophageal septum
What is an azygous lobe?
Part of superior Right lung lobe grows medial to azygous vein, rather than completely lateral to it.
Forms a little mini-me lobe.
Most common cause of lung hypoplasia?
Congenital diaphragmatic hernia
How does bilateral renal agenesis affect the lungs?
Renal agenesis keeps urine from being produced. This creates oligohydramnios. Without enough amniotic fluid the lungs will not begin to expand and they will underdevelop
Also see Potter’s syndrome
There are 4 stages of lung maturation in the developing fetus.
What is the name of the first stage from 6-16 weeks?
Why can’t infants born at this time survive?
Pseudoglandular stage.
Bronchi/bronchioles have developed, but no alveoli are present!
There are 4 stages of lung maturation in the developing fetus.
What is the name of the 2nd stage from 16-26 weeks?
Can infants breathe if born at this stage?
Canicular Stage.
Bronchioles and alveolar ducts have developed and they have been vascularized.
Breathing is now possible
There are 4 stages of lung maturation in the developing fetus.
What is the 3rd stage from 26 weeks to birth?
What are the highlights?
Terminal Sac Stage.
Type1/2 alveolar pneumocytes are produced. Surfactant is produced, which lowers alveolar surface tension
There are 4 stages of lung maturation in the developing fetus.
The last stage is 32weeks to 8years old. What is developing then?
Alveolar stage.
Alveoli mature and increase in number
What can you give to a possible premie to help develop their lungs during pregnancy?
glucocorticoids
What is the embryology of an esophageal atresia?
Incomplete division of cranial part of the foregut!
If a child has an esophageal atresia, but also has air in the bowel. What does this suggest?
Bowel air must be swallowed. Clue that there is a distal fistula
Infant is born emergency C-section premature, cyanotic, severe retraction, with CXR showing “ground glass” in lung fields.
What is the disorder and what is the underlying pathology?
Tx?
Respiratory distress syndrome
Immature type2 pneumocytes have not produced enough surfactant yet
Tx: artificial surfactant