GI embryology

Question 1

which germ layers are the GI tract derived from

Answer 1

endoderm, visceral mesoderm, neural crest

Question 2

what does endoderm form in GI tract

Answer 2

epithelium of mucosa

associated ducts and glands

Question 3

what does visceral mesoderm form in GI tract

Answer 3

lamina propria
muscalris mucosa
muscalris externa 
submucosa connective tissue 
external connective tissue

Question 4

what does the neural crest form in GI tract

Answer 4

ENS
Myenteric plexus
Aucherbach’s plexus

Question 5

when is the myenteric plexus visible

Answer 5

week 8

Question 6

when is the aucherbach’s plexus visible

Answer 6

week 12

Question 7

what are mesenteries of the gut derived from

Answer 7

mesoderm

Question 8

what are ventral mesenteries derived from

Answer 8

remenants of septum transversum

Question 9

what are the dorsal mesenteries derived from

Answer 9

connection between visceral and somatic part of lateral plate mesoderm

Question 10

what are the ventral mesenteries

Answer 10

falciform ligament

lesser omentum

Question 11

what are the dorsal mesenteries

Answer 11

dorsal mesogastrium
dorsal mesoduodenum
mesentery proper
dorsal mesocolon

Question 12

which structures are retroperitoneal

Answer 12

thoracic oesophagus 
pancreas
duodenum
ascending colon
descending colon 
rectum 
anus

Question 13

when is the oesophagus distinguishable

Answer 13

end of week 4

Question 14

when does the circular muscle of the oesophagus develop

Answer 14

week 5

Question 15

when is the spleen present

Answer 15

week 5

Question 16

what is the spleen derived from

Answer 16

dorsal mesentery

Question 17

when does the spleen become a lymphatic organ

Answer 17

week 15-18

Question 18

what is the spleen before it is an lymphatic organ

Answer 18

haematopoietic

Question 19

what is the liver and gallbladder an outgrowth of

Answer 19

duodenum

Question 20

the endoderm males up what part of the liver and gallbladder

Answer 20

liver cells and lining of the biliary tree

Question 21

the septum transverse makes up what part of the liver and gallbladder

Answer 21

Hematopoietic cells
Kupffer cells
connective tissue

Question 22

during development what is the main site of RBC production

Answer 22

liver

Question 23

what does the pancreas start as two outgrowths from

Answer 23

duodenum

Question 24

which pancreatic bud is larger

Answer 24

dorsal

Question 25

which pancreatic bud grows at the same point as the liver bud

Answer 25

ventral

Question 26

what duct migrates with the ventral bud to the dorsal bud

Answer 26

common bile duct

Question 27

what part of the pancreas does the ventral bud form

Answer 27

uncinate process

Question 28

what part of the pancreas does the dorsal bud form

Answer 28

upper part body tail

Question 29

what is a minor duodenal papilla

Answer 29

when the dorsal pancreatic bud keeps its communication into duodenum

Question 30

what is an annular pancreas

Answer 30

pair of ventral buds develop one moves posterior one moves anterior surrounds duodenum putting pressure on it

Question 31

which artery supplies the foregut

Answer 31

celiac artery

Question 32

which artery supplies the midgut

Answer 32

superior mesenteric artery

Question 33

which artery supplies the hindgut

Answer 33

inferior mesenteric artery

Question 34

when is the swelling of the forgut (stomach) distinguishable

Answer 34

end of week 4

Question 35

when the stomach rotates 90 degrees along its longitudinal axis where do the vagus nerves lie

Answer 35

left vagus nerve becomes anterior | right vagus nerve becomes posterior

Question 36

which mesentery grows faster

Answer 36

dorsal

Question 37

what does the midgut communicate with for most of its development

Answer 37

yolk sac

Question 38

what does the primary intestinal loop rotate around

Answer 38

superior mesenteric artery

Question 39

where does the caecal bud form

Answer 39

caudal limb of primary intestinal loop

Question 40

when does re entry to body cavity occur

Answer 40

week 10

Question 41

when is the vitelline duct to the yolk sac lost

Answer 41

after re-entry

Question 42

what is a Meckel diverticulum

Answer 42

vitelline duct doesn't regress after re entry and there is an anchor point for small intestine

Question 43

what does a vitelline cyst cause

Answer 43

anchoring point for small intestine

Question 44

what is a vitelline fistula

Answer 44

when vitelline duct remains open at umbilicus

Question 45

what does non rotation of small intestine cause

Answer 45

displaced midgut structures

Question 46

what does malrotation of midgut on re entry cause

Answer 46

duodenum crosses transverse colon anteriorly not posteriorly

Question 47

what divides the cloaca into anterior and posterior segments

Answer 47

urorectal septum

Question 48

what does the anterior segment of cloaca form

Answer 48

primitive urogenital sinus

Question 49

what does the posterior segment of cloaca form

Answer 49

anorectal canal

Question 50

what is a urorectula fistula

Answer 50

failure of complete separation of cloaca in males

Question 51

what is a rectoperineal fistula

Answer 51

communication between rectum and bladder