Embryology 3 Flashcards
what does the tubular outgrowth from foregut (oesophagus) develop into?
the trachea and lung buds
what happens when the lung buds proliferate?
they will invaginate laterally into the pleural cavities, so forming visceral and parietal pleura and the pleural cavity
how is the diaphragm formed
whilst the parts of the trachea and lungs are forming a transverse septal ‘shelf’ develops between thorax and abdomen below the pleural cavities
what is the septal ‘shelf’ composed of
4 components that fuse to form the diaphragm
how do congenital abnormalities come about?
things can go wrong with the embryonic tracheal, lung and diaphragmatic formation
what does folding of the embyro during week 3 give rise to?
the primitive gut tube
what comes from the midgut and hindgut
gut
what comes from the ventral wall of the foregut
trachea and lungs
when does tracheal and lung development start
4 weeks gestation
how does the trachea start to develop
a median outgrowth called the laryngotracheal groove from the ventral part of the foregut
how do the trachea and oesophegus separate
oesophagotracheal septum - that completely separates them into trachea ventrally and oesophagus dorsally - a relationship that is maintained into adulthood.
what is Tracheoesophageal fistula
A fistula is an abnormal connection or passageway that connects two organs or vessels that do not usually connect
TOF is a common congenital abnormality.
Define atresia
a condition in which a passage in
the body is closed or absent (abnormal to usual anatomy)
lining of the thoracic wall
becomes lined by a layer ofparietal pleura, derived from somatic mesoderm
what is the gap between the parietal and visceral pleurae called
called pleuroperitoneal canals - these eventually become the pleural canals
during lung development, when are the alveolar sacs formed?
during 27-40 week period
alveolar sacs will be progressively divided into smaller subunits leading to the formation of alveoli later on
what is respiratory distress syndrome (RDS)
- acute lung disease caused by surfactant deficiency, which leads to alveolar collapse and noncompliant lungs (underdeveloped lungs basically)
- Affects 2 % of neonates
what does the septum transversum become in the diagphragm
the central tendon
what do the pleuroperitoneal membranes become
the primitive diaphragm
what does the dorsal mesentery of oesophagus become
the median portion and crura (leg shaped tendons) of the diaphragm
which embryonic components make up the peripheral parts of diaphragm
muscular ingrowth from lateral body walls
what 4 embryonic components develop into the diaphragm
Septum transversum Pleuroperitoneal membranes
Dorsal mesentery of oesophagus
Muscular ingrowth from lateral body walls
where is the septum transversum initially located?
opposite C3-C5 somites
it migrates caudally
3 major congenital defects during diaphragm development
Failure of the diaphragm to completely close during development
Herniation of the abdominal contents into the chest
Pulmonary hypoplasia
define hernia
bulge or protrusion of an organ through the structure or muscle that usually contains it.
what 3 types of diaphragmatic herniae can you get?
- posteriolateral (Bochdalek) hernia
- anterior (Morgagni) hernia
- central hernia
what 2 types of hiatal herniae can you get
a hernia through the holes in the diaphragm
- sliding hiatus hernia
- paraesophageal hiatus hernia ‘rolling’ hiatus hernia
