Embryology: Development of the peritoneum and foregut Flashcards Preview

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Flashcards in Embryology: Development of the peritoneum and foregut Deck (12)
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1
Q

Outline the embryonic folding in the 4th week

A

Lateral folding - creates a ventral wall and forms a tubular primitive gut
Craniocaudally - creates cranial and caudal pockets from the yolk sac endoderm which is the beginning of primitive gut development

2
Q

What is the primitive gut tube?

A

The primitive gut tubes pinches off from the yolk sac in the 3rd week
It runs from the future mouth to the future anus with an opening at the umbilicus

3
Q

What is the germ layer derivative of the primitive gut tube?

What will each lining become?

A

Internal lining derived from endoderm and will become the future epithelial linings
External lining derived from splanchnic mesoderm and will become future musculature and visceral perioteum

4
Q

What is the arterial supply of the foregut, midgut and hindgut?

A

Foregut - celiac trunk
Midgut - superior mesenteric artery
Hindgut - inferior mesenteric artery

5
Q

What is the intraembryonic coelom?

A

Begins as one large cavity the entire length of the embryo then is subdivided by the future diaphragm into abdominal and thoracic cavities.

6
Q

What is mesentery formed out of?

A

The primitive gut is suspended in the intraembryonic coelum by splanchnic mesoderm
The mesentery is formed by a condensation of this splanchnic mesoderm

7
Q

What do the dorsal and ventral mesenteries suspend?

A

Dorsal mesentery suspends the entire gut tube from the dorsal body wall
Ventral mesentery only suspends the foregut creating a free edge

8
Q

In the foregut how are the greater and lesser peritoneal sacs formed?

A

There are both ventral and dorsal mesenteries so these divide the cavity into left and right sac

  • the left sac contributes to the greater sac
  • the right sac becomes the lesser sac
9
Q

What are the greater and lesser omenta?

A

Omenta are specialised regions of peritoneum

  • the greater omentum is formed from dorsal mesentery
  • the lesser omentum is formed from ventral mesentery
10
Q

What is formed when there is rotation of the primitive stomach?

A
  • The cardia and pylorus move horizontally which pushes the greater curvature inferiorly
  • Puts he vagus nerve anterior and posterior of the stomach
  • Creates the greater omentum
  • Puts the lesser sac behind the stomach
11
Q

What is the difference between retroperitoneal and secondarily retroperitoneal structures?

A

Retroperitoneal structures were never in the peritoneal cavity and never had a mesentery
Secondarily retroperitoeal structures began development in the peritoneum and had a mesentery which then regresses through fusion to the posterior abdo wall
(eg duodenum except cap, pancreas)

12
Q

What are some consequences of abnormal positioning of the tracheoesophageal septum?

A

Can get a range of oesophageal abnormalities (1 in 3000 live births)

  • blind end oesophagus and a tracheoesophageal fistula
  • 2 parts of blind ended oesophagus
  • 2 tracheoesophageal fistulas

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