Embryology 3 - Development of resp system Flashcards
How far into gestation do the trachea and lungs begin to develop?
4 weeks in
From what area do the trachea and lungs develop?
Ventral wall of the foregut
Development begins with formation of larygo-tracheal groove
The first stage of development of the respiratory system is the…
Formation of larygo-tracheal groove from the ventral part of the foregut - pharynx area
Describe how the trachea separates from the oesophagus
The oesophagotracheal septum develops develops between the oesophagus and the trachea and eventually separates them
What is a fistula?
Abnormal or surgically made passage between a tubular organ and the body surface, or between two hollow or tubular organs
Give an example of a fistula
Tracheoesophageal fistula
What is an atresia?
A condition in which an oriface or passage in the body is closed or absent
What is the parietal pleura derived from?
Somatic mesoderm
What is the visceral pleura derived from?
Splanchnic mesoderm
Describe how the pleura and pleural cavity are formed
The lungs begin to develop and ‘punch’ into the splanchnic mesoderm, so they acquire a layer a visceral pleura from the splanchnic mesoderm
The thoracic wall becomes lined by the somatic mesoderm which forms the parietal pleura
The space between the parietal and visceral pleura is the pleuropericardial canals (this becomes the pleural cavity)
What are the stages of lung development?
Embryonic 4-7 Pseudoglandular 7-17 Canalicular 17-27 Saccular 27-40 Alveolar - post-natal
What is surfactant made of?
Phospholipids and proteins
What is RDS?
Respiratory distress syndrome (aka hyaline membrane disease HMD)
Surfactant deficiency is a major cause of RDS
How many neonates suffer from RDS?
2% of neonates affected
30% of neonatal disease
What are the main neonatal congenital conditions with development of the lungs?
RDS
Accessory lobes
Azygos lobe
Agenesis of lung
The septum transversum forms the ______
Central tendon of the diaphragm
The Pleuroperitoneal membranes form the _____
primitive diaphragm
The Dorsal mesentery of oesophagus forms the ______
median portion & crura of diaphragm
The Muscular ingrowth from lateral body walls forms the ______
peripheral parts of diaphragm
Describe the development and movement of the septum tranversum during foetal development
ST initially located opposite the C3-C5 somites (week 3)
It migrates caudally during the development of the diaphragm and takes down the spinal nerves from C3-C5 with it
(These spinal nerves = the phrenic nerve)
What are the major congenital abnormalities with the development of the diaphragm?
- Failure to completely close during development
- Herniation of abdominal contents into chest
- Pulmonary hypoplasia
What is a herniation?
Bulge/protrusion of an organ through the structure/muscle which should contain it
What 2 basic types of hernia’s can take place with the diaphragm?
Diaphragmatic hernia
Hiatal hernia
The somatic mesoderm forms _____
Parietal pleura
