Body Cavities Flashcards
Isolated spaces in the _____ will form the Intraembryonic Coelom
Lateral plate mesoderm AND
Cardiogenic mesoderm
What shape is the intraembryonic coelom?
Horseshoe-shaped (U)
What is the embryonic body cavity?
Intraembryonic coelom
The growth of the intraembryonic coelom will separate the lateral plate mesoderm into what 2 layers?
- Somatic (parietal) lateral mesoderm
2. Splanchnic (visceral) lateral mesoderm
Somatic lateral mesoderm + overlying ectoderm =
Somatopleure
What will the somatopleure eventually form?
Body wall
Splanchnic lateral mesoderm + underlying endoderm =
Splanchnopleure
What will the splanchnopleure eventually form?
Gut
The intraembryonic coelum will be divided into what 4 cavities?
- Pericardial cavity
- 2 Pleural cavities
- Peritoneal cavity
What mesothelium will line the parietal wall (peritoneum)?
Somatic mesoderm
What mesothelium will line the visceral wall (peritoneum)?
Splanchnic mesoderm
When does head folding occur?
4th week (day 22)
Describe head folding
Neural folds project and overgrow the oropharyngeal membrane to push primordial heart and pericardial cavity inferior to correct location
Head fold movements reshape the pericardial cavity to what location?
Ventral and anterior to the foregut
Head fold movements reshape the 2 pericardioperitoneal canals to which locations?
Dorsal and on each side of the foregut
The pericardial cavity opens into what 2 canals?
2 Pericardioperitoneal canals
Describe tail folding
Caudal eminence projects over the cloacal membrane
After tail folding, where is the primitive streak?
Caudal
With lateral folding, what grows rapidly to cause it and the tissues extend which direction?
The spinal cord and somites grow rapidly
- Lateral folds extend ventrally
With lateral folding, what wall forms?
Abdominal wall
With lateral folding, the connection between the umbilical vesicle and midgut gets reduced to form?
Vitelline duct
With lateral folding, the connection between the IE and EE coelom is narrowed to form?
Umbilical cord
What will eventually expand and obliterate the EE coelom?
Amniotic cavity
Body wall malformations involve the failure of?
Lateral body folds to fuse completely and form the anterior abdominal wall
Gastroschisis
Protrusion of viscera to the RIGHT
- Bowel UNcovered
Congential Epigastric Hernia
MIDLINE bulge of abdominal wall
- Bowel COVERED with skin and subcutaneous tissues
What 2 folds from at the top and bottom of the pericardioperitoneal canals to form separate cavities?
- Pleuropericardial folds
2. Pleuroperitoneal folds
The pleuropericardial folds separate?
Pericardial cavity and pleural cavities
- heart and lungs
The pleuroperitoneal folds separate?
Pleural cavities and peritoneal cavity
- lungs and gut
The pleuropericardial folds and pleuroperitoneal folds are outgrowths of the?
Lateral body wall
As the pleuropericardial folds and pleuroperitoneal folds enlarge, they form?
Pleuropericardial membrane
Pleuroperitoneal membrane
The pleuropericardial membranes fuse with ventral mesenchyme at what week?
7th week
What causes the pleural cavities to expand?
Outgrowth of bronchial buds (lungs) into the pericardioperitoneal canals
As the pleural cavity expands, what does it split the mesenchyme into?
- Outer layer = thoracic wall
2. Inner layer = fibrous pericardium
____ contribute to the pleuroperitoneal membranes to complete their closure
Myoblasts
Which pleuroperitoneal opening closes first?
RIGHT one
What does the pleuroperitoneal membrane fuse with?
Dorsal mesentary of the esophagus and
Septum transversum
The septum transversum creates what part of the diaphragm?
Central tendon
The pleuroperitoneal membranes create what part of the diaphragm?
Primordial diaphragm
The dorsal mesentary of the esophagus creates what part of the diaphragm?
Median portion
The myoblasts create what part of the diaphragm?
Crura of diaphragm
Describe how the diaphragm becomes innervated via the phrenic nerve
- Myoblasts pull C3-C5 ventral rami with them
- Pass through the pleuropericardial membranes
- Phrenic nerve subsequently lies on the fibrous pericardium to innervate the diaphragm
Congenital diaphragmatic hernia
Lack of myoblasts populating pleuroperitoneal membranes = area of weakness and viscera can bulge into pleural cavities
Which side is usually impacted the most by a congenital diaphragmatic hernia?
LEFT side
What may be delayed with a congenital diaphragmatic hernia?
Lung development
