GI Development Flashcards
What is the intraembryonic coelem?
The primordium (organ in earliest stage of development) of the embryonic body cavity.
What does the intraembryonic coelem give rise to?
PERICARDIAL CAVITY
2 PERICARDIOPERITONEAL CANALS (connect pericardial cavity and peritoneal cavity)
LARGE PERITONEAL CAVITY
The PARIETAL wall of the of the intraembryonic coelem is derived from what?
SOMATIC MESODERM
The VISCERAL wall of the of the intraembryonic coelem is derived from what?
SPLANCHNIC MESODERM
What do the “limbs” represent on the intraembryonic coelom?
The DISTAL part of each limb of the intraembryonic coelom is continuous with what?
Limbs of the intraembryonic coelom represent the future pleural and peritoneal cavities.
EXTRAEMBRYONIC COELEM
Where does midgut of the hernia go through?
It will go through the communication spot between the intra and extra embryonic coelom.
Where does pericardial cavity open into ?
Opens into the right and left pericardioperitoneal canals.
What is the septum transversum?
Where does the septum transversum sit?
It is a thick plate of mesoderm
It sits in between the thoracic cavity and the vitelline duct.
What does the septum transversum eventually become?
CENTRAL TENDON OF THE DIAPHRAGM
What happens in the 5th week at the junction between the unpaired pericardial cavity and the 2 pericardioperitoneal canals?
What vein and nerves do they contain?
They start growing towards each other. (form a triangle almost)
They contain the COMMON CARDINAL VEIN (the trunk of it) and the PHRENIC NERVES
How do the pleural cavities form?
Pleural cavities form as a result of the lung buds growing into the pericardioperitoneal canals
When do the pleural cavities (house the lungs) officially become SEPARATED?
Where does the separation of the PLEURAL CAVITIES take place?
Once the pleuropericardial membranes have fused with the mesenchyme
At THE ROOT OF THE LUNGS.
There is a right and left pleuropericardial membranes
What gives rise to the future FIBROUS PERICARDIUM?
Right and Left pleuropericardial membranes. (2 of them)
After separation of the pleural cavities, how is the pleural cavity connected (temp) to the peritoneal cavity?
Through the PERICADRIOPERITONEAL CANALS
Where is the peritoneal cavity connected to the extraembryonic coelom?
At the umbilicus
What are the 4 embryonic structures that help develop the DIAPHRAGM?
Septum Transversum
2 Pleuroperitoneal membranes
Dorsal mesentery of the esophagus
Muscular components of the 3rd-5th cervical somites
What part of the diaphragm does the septum transversum help form?
CENTRAL TENDON OF THE DIAPHRAGM
What part of the diaphragm does the 2 pleuroperitoneal membranes help form?
EARLY DIAPHRAGM
What forms the median portion of the diaphragm?
DORSAL MESENTERY OF THE ESOPHAGUS
What does the crura of the diaphragm develop from?
Myoblasts the grow into the dorsal mesentery of the esophagus
What forms the muscular part of the diaphragm?
Muscular components of the 3rd-5th cervical somites
What is the most common cause of pulmonary HYPOplasia (incomplete development of lungs)?
(portions of GI tract literally go into the thoracic cavity).
CONGENITAL DIAPHRAGMATIC HERNIA (CDH)
What is congenital diaphragmatic hernia (CDH)?
It is posterolateral defect caused by the failure of 1 or both of the pleuroperitoneal membranes (usually the left one).
It is common (1 in 2200 newborns)
What 2 membranes close the primordial gut?
OROPHARYNGEAL MEMBRANE (cranial end)
CLOACAL MEMBRANE (caudal end)
What are the epithelium at both the cranial and caudal end of the GI tract called?
(Derived from ectoderm)
STOMEDEUM (cranial end)
PROCTODEUM (caudal end)
What is the primordial gut divided into? (4 parts)
Pharynx
Foregut
Midgut
Hindgut
What are the derivates of the foregut?
How do they receive blood?
Lower respiratory system, esophagus, stomach, first 2 parts of dueodenum, liver, pancreas, biliary apparatus (hepatic ducts, bile duct, gallbladder)
Celiac trunk delivers blood (except for the pharynx, resp. tract, and upper 2/3rd of esophagus)
What does the respiratory diverticulum elongate into?
Laryngotracheal tube (this tube initially opens into the foregut)
Where does the respiratory diverticulum develop?
It is a protrusion on the ventral (top) part of the foregut.
What separates the laryngotracheal tube from the foregut?
Tracheoesophageal septum
What can result when there is abnormal separtion/partioning of the esophagus and trachea at the tracheoesophageal septum?
Esophageal atresia
Either with or without tracheoesophageal fistulas (TEFs) - abnormal pairing between trachea and esophagus
Describe the most frequent TEF (tracheoesophageal fistula)
Upper esophagus ends in a blind pouch and the lower segment of the esophagus forms a fistula with the trachea (abnormal pairing between lower part of esophagus and trachea)