embryology of the respiratory system Flashcards
where does the laryngotracheal groove bud from?
the foregut
what does the laryngotracheal tube develop into?
trachea and lung buds
how is the laryngotracheal tube and the oesophagus separated?
the oesophagotracheal septum grows between the two tubes
what is another name for the laryngotracheal groove?
diverticulum
which embryonic structure forms the central tendon of the diaphragm?
the septum transversium
explain why the diaphragm has innervation from C3, 4 and 5?
the septum transversium originates from the cervical region of the embryo and migrates down to its final level. When it does this it drags its nerve supply with it forming the phrenic nerve
at what week of gestation does the embryo fold?
week 3
at what stage of gestation does the diverticulum form?
week 4
what is a fistula?
an abnormal or surgically made passage between a hollow or tubular organ and the body surface, or between two hollow or tubular organs, ie. between 2 epithelialized surfaces.
what is a tracheoesophageal fistula?
a passage between the trachea and the oesophagus
what is atresia?
a condition in which an orifice or passage in the body is (usually abnormally) closed or absent.
what embryonic structure gives rise to the visceral pleura?
the splanchnic mesoderm (splanchnopleure)
what embryonic structure gives rise to the parietal pleura?
the somatic mesoderm (somatopleure)
what separates the pleural cavities from the pericadial cavity?
pleuropericardial folds
what is the gap between the parietal and visceral pleura called (before the diaphragm is formed completely)?
the pericardioperitoneal canal
what do the lung buds differentiate in to as they proliferate?
visceral (splanchnic) mesoderm into the pericardioperitoneal canals
what are the 5 stages if differentiation of lung buds?
embryonic pseudoglandular canalicular saccular alveolar
when does the majority of the alveolar stage of lung development occur?
postnatally
what are some congenital conditions of the lungs?
- RDS
- accessory lobe (extra lobe)
- azygos lobe (azygous vein infiltrates lung to give the appearance of an extra lung)
- agenesis of lung (lung does not form
what are the 4 embryonic components of the diaphragm?
- septum transversium
- pleuroperitoneal membranes
- dorsal mesentary of oesophagus
- muscular ingrowth from lateral body walls
what part of the diaphragm does the septum transversium form?
the central tendon
what part of the diaphragm do the pleuroperitoneal membranes form?
the primitive diaphragm
what part of the diaphragm does the dorsal mesentery of the oesphagus form?
median portion and crura
what part of the diaphragm does the muscular ingrowth from the lateral body walls form?
peripheral parts of the diaphragm
what are the two major congenital defects of the diaphragm?
- Failure of the diaphragm to completely close during development
- Herniation of the abdominal contents into the chest
what is pulmonary hypoplasia?
the incomplete development of the lung
where are the three most common places for a diaphragmatic hernia?
- posteriolateral
- anterior hernia
- central hernia (in central tendon)
what is a sliding hiatus hernia?
the stomach protrudes through the oesophageal hiatus pushing the oesophagus up
what is a paraoesophageal hernia?
the stomach “rolls” up the oesophagus so it passes through the hiatus beside it
