Development of the Peritoneal Cavity and the Foregut Flashcards Preview

2.3.5. Gastrointestinal System > Development of the Peritoneal Cavity and the Foregut > Flashcards

Flashcards in Development of the Peritoneal Cavity and the Foregut Deck (26)
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1
Q

How do we get an anterior body wall?

A

Folding of the embryo

Lateral folding = creates ventral body wall

2
Q

What does folding in the 4th week of the embryo achieve?

A

Laterally = ventral body wall, primitive gut becomes tubular

Craniocaudally = cranial + caudal pockets from yolk sac endoderm

3
Q

What is the primative gut?

A

Lined by endoderm – devel into the lining and glands

Runs from stomatodeum (future mouth) rostrally to proctodeum (future anus) caudally

Blind pouches at the head and tail end

Opening at umbilicus

Splanchnic mesoderm covering

4
Q

How does the primitive gut form?

A

Craniocaudally folding = cranial + caudal pockets from yolk sac endoderm (begining of primative gut tube formation

Lateral folding = primative gut becomes tubular

5
Q

What is somatic mesoderm vs splanchnic mesoderm?

A

Somatic = relating to the body, lining body wall

Splanchnic = relating to the viscera

6
Q

What are the 3 divisions of the primitive gut tube?

A

Foregut

Midgut

Hindgut

7
Q

What does the embryonic foregut turn into?

A

Oesophagus

Stomach

Pancreas, liver, gall bladder

Duodenum (proximal to bile duct entrance)

8
Q

What does the embryonic midgut turn into?

A

Duodenum (distal to bile duct entrance)

Jejunum

Ileum

Cecum

Ascending colon

Proximal 2/3 transverse colon

9
Q

What does the embryonic hindgut turn into?

A

Distal 1/3 transverse colon

Descending colon

Sigmoid colon

Rectum

Upper anal canal

Internal lining of bladder, urethra

10
Q

How is the primitive gut tube related to the blood supply of the GI tract?

A

Each section of the primitive gut tube receives a distinct branch from the abdo aorta

Foregut = celiac trunk

Midgut = superior mesenteric artery

Hindgut = inferior mesenteric artery

Structures close to junctions receives a mixed blood supply

11
Q

What is the intraembryonic coelom?

A

Cavity, divided by diaphragm that will give rise to the thoracic and abdo cavities

Formed as the embryo folds

Begins as one large cavity from top to bottom of the embryo

12
Q

Define mesentery

A

Double layer of peritoneum suspending the gut tube from the abdo wall

Allows conduit or blood and nerve supply

Allows mobility where needed

13
Q

How does the mesentery form?

A

Primitive gut tube drops down into the intraembryonic coelom

Splanchnic mesoderm is dragged down = forms mesentery

14
Q

Where is mesentery found?

A

Dorsal mesentery = suspends entire gut tube from dorsal body wall

Ventral mesentery = only in the region of the foregut

15
Q

What is the greater sac of the abdo?

A

Sac inside the abdo but outside the lesser sac

16
Q

What is the lesser sac of the abdo?

A

Through the epiploic foramen, behind the stomach

17
Q

What is the omenta?

A

Specialised regions of peritoneum

18
Q

What is the greater omentum?

A

Formed from the dorsal mesentery

Hangs down from the stomach, doubles back to the transverse colon before reaching the posterior abdo wall

First structure seen in abdo cavity

19
Q

What is the lesser omentum?

A

Formed from ventral mesentery

Runs from stomach to liver, free edge conducts portal triad

Smaller, short

20
Q

What influences the position of the great and lesser omentum?

A

Rotation of the stomach around the long axis during devel

21
Q

What is secondary retroperitoneal?

A

Began devel invested by peritoneum, has a mesentery but with devel the mesentery is lost through fusion at posterior abdo wall, due to massive expansion of the GI tract

22
Q

What separates the devel GI and resp tracts?

A

Tracheoesophageal septum

23
Q

What structures have mesenteries?

A

Jejunum

Ileum

Stomach

Uterus

Transverse colon

24
Q

What structures are retroperitoneal?

A

Pancreas

Kidneys

aorta

25
Q

What structures are secondary retroperitoneal?

A

Pancreas

Duodenum

Descending colon

26
Q

What is fusion fascia?

A

The point at which the mesentery is lost and fuses with the membrane