Lecture 4: Respiratory Embryology Flashcards
Where does the respiratory system start from?
Laryngotracheal groove (median outgrowth)
- on the floor of the caudal foregut
- inferior to the 4th pharyngeal arch
What does the endoderm of the laryngotracheal groove give rise to?
Pulmonary epithelium and glands of:
- larynx
- trachea
- bronchi
What does the splanchnic mesoderm of the laryngotracheal groove give rise to?
CT, cartilage, and smooth muscles that surround foregut
What will the laryngotracheal groove evaginate into?
Laryngotracheal diverticulum –> respiratory bud
What is the function of the tracheoesophageal fold?
Divides esophagus (dorsal) from trachea (ventral)
How does the laryngeal inlet form?
Mesenchyme from pharyngeal arches 4 and 6 promote arytenoid swellings, converting primordial glottis into a laryngeal inlet
How does the laryngeal inlet form a bigger opening?
Briefly, over-proliferation of epithelium will occlude the inlet. However, recanalization and apoptosis will remove epithelium revealing a larger inlet and laryngeal ventricles.
Where does the epiglottis develop from?
Hypopharyngeal eminence
-produced from mesenchyme from pharyngeal arches 3 and 4
Where does the trachea develop from?
Laryngotracheal tube
What is a tracheoesophageal fistula?
Abnormal connection between trachea and esophagus
What is the most common form of a tracheoesophageal fistula?
Esophageal atresia: upper esophagus and does not connect with the lower esophagus and stomach
What can cause a tracheoesophageal fistula?
Foregut endoderm does not proliferate fast enough
What are some symptoms of a tracheoesophageal fistula?
Cannot swallow Frequently drools saliva Immediate regurgitation Polyhydramnios Excess air in GI tract
How are primary bronchial buds formed?
From respiratory buds
-grow vetrocaudally and bifurcates
Where do primary bronchial buds grow to?
Grows laterally to pericardioperitoneal canals
