Respiratory - Embryology Flashcards
When is the pre-embryonic phase?
0-3 weeks
When is the embryonic phase?
4-8 weeks
When is the foetal phase?
9-40 weeks
What is the primitive structure of the respiratory system?
Foregut of primitive gut tube
What is the primitive structure of the lung buds?
Ventral wall of primitive foregut
What is the primitive structure of the trachea?
Ventral wall of primitive foregut
What is the primitive structure of the Ventral trachea and dorsal oesophagus?
Oesphagotracheal septum (between these 2 structures separating them)
What is the primitive structure of the lungs?
Lung buds (enlarge)
What is the primitive structure of the visceral pleura?
Splanchnic layer of lateral plate mesoderm
What is the primitive structure of the parietal pleura?
Somatic layer of lateral plate mesoderm
What is the primitive structure of the central tendon of diaphragm?
Septum transversum
What grows in from the periphery and fuse with septum transversum?
Pleuroperitoneal folds
What is the primitive structure of the muscular part of diaphragm?
Skeletal muscle ingrowth from periphery
What is the primitive structure of the diaphragm?
Dorsal mesentery of oesphagus
What happens in the following stage?
Embryonic
3-17 weeks
Lung buds start to develop as a respiratory diverticulum from the foetal foregut
What happens in the following stage?
Pseudoglandular 7-17 weeks
Development of all lung structures exept respiratory part (no gas exchange)
What happens in the following stage?
Canalicular 17-27 weeks
Formation of respiratory part, Alveolar ducts form and epithelium starts to differentiate into Type I and Type II pneumocytes (still no gas exchange)
What happens in the following stage?
Saccular 27-40 weeks
Formation of alveolar sacs, primitive alveoli, and surfactant. Gas exchange begins
What happens in the following stage?
Alveolar 32 weeks – 8 years
Proliferation of alveoli from alveolar sacs.
About 95% of adult alveoli formed postnatally. 300m alveoli in adult
