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Flashcards in Embryology 1 Deck (45)
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Consequences of stomach rotation

Original left side becomes anterior (greater sac)
Original right side becomes posterior (lesser sac)
Vagus nerve lies anterior/posterior instead of left/right
Shifts cardia and pylorus from the midline
Creates the greater omentum


What is meant by a peritoneal reflection

A change in direction/reflections of peritoneum
- mesentery to visceral peritoneum (and vice versa)
- mesentery to parietal peritoneum (and vice versa)


What determines the mobility of abdominal contents

Whether it has a mesentery or not


Define retroperitoneal organs and give some examples

Were never in the peritoneal cavity and therefore don't have a mesentery
E.g kidneys, aorta, oesophagus


Define secondary retroperitoneal organs and give some examples

Began development invested by peritoneum and had a mesentery but with progressive growth the mesentery is lost by fusion at the posterior abdominal wall
E.g ascending colon, descending colon, duodenum


Why is the duodenum secondary retroperitoneal

Rotation of the stomach pushes the duodenum against the posterior abdominal wall because the liver is so large


How is fusion fascia created

Peritoneum of the posterior abdominal wall is squished together with the duodenum and its mesentery and grows over it, creating fusion fascia


How can the duodenum be made mobile

Removal of fusion fascia (avascular so no damage)


What happens to the duodenum during weeks 5-6

Lumen is obliterated due to rapid growth of its lining
It's recanalised by the end of the embryonic period (before week 9)


When and where is the respiratory diverticulum created

Week 4
In the ventral wall of the foregut at the junction with the pharyngeal gut


What does the respiratory diverticulum become and how

Ventrally - respiratory primordium
Dorsally - oesophagus
Divided by the tracheoesophageal septum


Incidence of abnormal positioning of the tracheoesophageal septum

Up to 1 per 3000 live births


Which foregut derived glands are formed in the ventral mesentery

Biliary system
Ucinate process and inferior head of pancreas


Which foregut derived glands are formed in the dorsal mesentery

Superior head, neck, body and tail of pancreas


What does the liver develop from

Hepatic bud