Embryology Flashcards
What are the lower respiratory organs?
Larynx
Trachea
Bronchi
Lungs
When does development of the lower respiratory organs begin?
Week 4 –> development of lung bud
What gives rise to the epithelial lining of the larynx, trachea, and bronchi?
Endoderm
What gives rise to the alveoli?
Endoderm
What gives rise to the cartilage, smooth muscle, and CT of the respiratory organs?
Splanchnic mesoderm
What is required for the appearance and development of the lung bud?
Increase in retinoic acid that upregulates transcription factor TBX4
What develops into the tracheo-esophageal septum?
Mesoderm
When do the primary bronchial buds develop?
Week 5
What has occurred in lung development from wk 5 to wk 24?
Subdivisions of primary bronchi into secondary, tertiary, intrasegmental branchs and respiratory bronchioles
What forms the parietal pleura?
Parietal/somatic mesoderm
What forms the visceral pleura?
Visceral/splanchnic mesoderm
How many additional divisions of the bronchial tree occur after birth?
6-7
When do the pericardium, pleura, and peritoneum start to separate?
Wk 7
What separates the pleural cavities from the pericardial cavity?
Pleuropericardial folds
What separates the pleural cavities form the peritoneal cavity?
Pleuroperitoneal folds
When is the pseudoglandular period?
Wks 5-16
When is the canalicular period?
Wks 16-26
When is the terminal sac period?
Wk 26 to birth
When is the alveolar period?
Birth to 8 yo
When does surfactant production start?
20-22 wks
When does adequate amount of surfactant production occur?
After wk 32
About how many of adult number of alveoli are present at birth?
1/6th
What can be a result of oligohydramnios in lung development?
Hypoplasia of lungs
What results from dilatation of terminal bronchioles in fetal life?
Congenital lung cysts
