4: Body Cavities Flashcards
Somatic vs splanchnic layer of lateral mesoderm
Somatic: continuous with extraembryonic mesoderm over amnion
Splanchnic: continuous with extraembryonic mesoderm over umbilical vesicle
Somatopleure
Somatic mesoderm + overlying ectoderm -> body wall/parietal peritoneum
Splanchnopleure
Splanchnic mesoderm + underlying endoderm -> embryonic gut / visceral peritoneum
What are the four body cavities lined with?
Mesothelium from somatic and splanchnic mesoderms
Where are the pericardioperitoneal canals located?
Dorsal to foregut
Where is the peritoneal cavity positioned?
Caudally, where intra and extraembryonic coeloms are continuous
Where do the pleuropericardial and pleuroperitoneal folds form from? **
Lateral body wall
What separation does the pleuropericardial folds make?
Anterior/posterior separation between heart and lungs
On which side does the pleuroperitoneal opening close first?
Right side first
What does folding in the three aspects form?
Turns the flat trilaminar embryonic disc -> cylindrical embryo
Where are pericardial cavity and pericardioperitoneal canals after head folding is finished?
Pericardial cavity: ventral
Pericardioperitoneal canals: dorsally on each side of foregut
What causes tail folding?
Growth of distal neural tube
What causes lateral folding?
Rapid growth of spinal cord and somites
Other name for vitelline duct
Omphaloenteric duct
What causes body wall malformations?
Failure of lateral body folds to fuse completely when anterior abdominal wall forms during 4th week
Gastroschisis
Protrusion of viscera -> bowel floating uncovered in amnionic fluid
Where is the defect in gastroschisis vs congenital epigastric hernia
Gastro: to the right of umbilical cord
Congenital epigastric hernia: midline
Congenital epigastric hernia
Midline bulge of abdominal wall between xiphoid and umbilicus -> bowel covered by skin and subq tissues still
Where do cardinal veins and myoblasts run through to reach diaphragm?
Pleuropericardial membranes
What do myoblasts pull with them to reach diaphragm? What does this cause?
Pull ventral rami C3-5 with them -> phrenic N lies on pericardium
Congenital diaphragmatic hernia
Area of weakness causes herniation of viscera into pleural cavity
What causes congenital diaphragmatic hernia
Lack of myoblasts populating peluroperitoneal membranes
Presentation of congenital diaphragmatic hernia
Lung maturation delay, possible polyhydramnios
