embryo

Question 1

What parts of the GI are from endoderm?

Answer 1

mucosal epithelium and GI glands

Question 2

What parts of the GI are from mesoderm?

Answer 2

muscular wall, smooth muscle, connective tissue, vasculature

Question 3

What parts of the GI are from ectoderm?

Answer 3

neural crest - enteric ganglia, nerves, glia

ectoderm- mouth and anal canal

Question 4

What are the derivatives of the foregut?

Answer 4

pharynx to proximal duodenum, liver, pancreas, gallbladder

Question 5

What are the derivatives of the midgut?

Answer 5

latter duodenum to right half of transverse colon, including appendix

Question 6

What are the derivatives of the hindgut?

Answer 6

left half of transverse colon to superior anal canal, epithelium of bladder and urethra

Question 7

What blood supplies the foregut?

Answer 7

celiac trunk

Question 8

What blood supplies the midgut?

Answer 8

superior mesenteric artery

Question 9

What blood supplies the hindgut?

Answer 9

inferior mesenteric artery

Question 10

Describe the rotation of the stomach in 4 events:

Answer 10

• ventral border rotates to the right
• dorsal border rotates to the left
• left side becomes ventral
• right side becomes dorsal

then growth and rotation along AP axis

Question 11

What are the prenatal and postnatal signs of a tracheoesophageal fistula?

Answer 11

prenatally: polyhydramnios
postnatally: coughing, gagging, cyanosis, vomiting, oral secretions, resp. distress

Question 12

What happens in hypertrophic pyloric stenosis? What are the presentations?

Answer 12

circular and longitudinal muscles hypertrophy

immediate post feeding vomiting, fewer and smaller stools, failure to gain weight

Question 13

What does the hepatic diverticulum give rise to?

Answer 13

liver, gallbladder and ventral pancreatic bud

the stalk becomes the hepatic duct and bile duct

Question 14

How does the pancreas form?

Answer 14

ventral pancreatic bud migrates to dorsal side.

Question 15

what does the dorsal pancreatic bud give rise to?

Answer 15

body and tail of pancreas

Question 16

what does the ventral pancreatic bud give rise to?

Answer 16

head and uncinate process

Question 17

what happens with an annular pancreas? whats the embryological causing?

Answer 17

obstruction of duodenum; symptoms similar to pyloric stenosis

head of pancreas is bifed; malrotation causes the site of duodenal obstruction

Question 18

what do we need to know about the spleen?

Answer 18

the spleen is foregut but is made from mesoderm

forms from week 5

is a hematopoetic organ and helps with hematopoesis in weeks 9-28

Question 19

how is midgut formed?

Answer 19

it herniates out into umbilicus at week 6, with the SMA becoming the axis

it then rotates 90 counterclockwise and a buldge appears for the cecum and the proximal part becomes convoluted

the proximal part returns into the abdomen, passes under distal portion towards the left and then the distal part returns

Question 20

what is an omphalocele? Which week?

Answer 20

failure of the bowel to return to body cavity (its covered by peritoneum); week 10

Question 21

What is gastroschisis? Which week does it happen in?

Answer 21

failure of body wall to close. no peritoneum. Week 4.

Question 22

What is the embryological mechanism of hirschsprung disease?

Answer 22

problem with neural crest cells; absence of ganglion

Question 23

What happens if you have midgut nonrotation?

Answer 23

SI on right side and LI on left side

usually no symptoms but could have higher likelihood of obstruction

Question 24

What happens with reverse rotation of midgut?

Answer 24

transverse colon becomes posterior to duodenum and can cause obstruction of TC;

caused by wrong 180 degree rotation

Question 25

How do we form the definitive gut lumen? What can go wrong?

Answer 25

epithelial cells fill lumen, then apoptosis and recanalization. duplication or stenosis

Question 26

What is the rule of 2s for meckels diverticulum?

Answer 26

``` 2% of population 2 feet from ileocecal junction 2 inches long 2 types of ectopic tissue (gastric and pancreatic usually) 2 years age of presentation 2x likely to affect males ```

Question 27

What is meckel's diverticulum caused by?

Answer 27

incomplete obliteration of vitelline duct, pulls on ileum and causes outpouching

Question 28

What is an omphalomesenteric fistula?

Answer 28

abnormal opening in the vitelline duct, causing poop to leave umbilicus

Question 29

What other two things could arise from Meckel's diverticulum?

Answer 29

omphalomesenteric cyst and omphalomesenteric ligament

Question 30

What does the urorectal septum separate the cloaca into?

Answer 30

urogenital membrane (forms bladder and urethra) and anal membrane (forms anus) both are ectoderm and endoderm

Question 31

What causes a congenital diaphragmatic hernia? What are the characteristics?

Answer 31

defective formation and/or fusion of the pleuroperitoneal membranes - large opening in posterolateral diaphragm herniation of abdominal contents, hypoplastic lungs, polyhydramnis

Question 32

Where does the mesentary come from?

Answer 32

splanchnic layer

Question 33

Where does the parietal peritoneum come from?

Answer 33

somatic layer of lateral plate mesoderm

Question 34

What is the purpose of the mesentaries?

Answer 34

to allow vessels to get to the organs; most of them degenerate

Question 35

What does the dorsal mesocardium give rise to?

Answer 35

transverse pericardial sinus

Question 36

What does the dorsal mesogastrium give rise to?

Answer 36

greater omentum

Question 37

What does the ventral mesogastrium give rise to?

Answer 37

lesser omentum

Question 38

What does the ventral mesentery give rise to?

Answer 38

falciform ligament

Question 39

What does the mesoduodenum give rise to?

Answer 39

mesentery around duodenum

Question 40

What does the mesentery proper give rise to?

Answer 40

mesentery containing jejunum and ileum

Question 41

What does the mesocolon give rise to?

Answer 41

mesentery around transverse colon and sigmoid colon

Question 42

What does the mesorectum give rise to?

Answer 42

mesentary around the rectum

Question 43

What ligaments does the dorsal mesogastrium give rise to?

Answer 43

splenorenal ligament and gastrolienal ligament

Question 44

Which structures are intraperitoneal?

Answer 44

stomach, tail of pancreas, first part of duodenum, jejunum, ileum, transverse colon, sigmoid colon

Question 45

Which structures are retroperitoneal?

Answer 45

pancreas (except tail), duodenum (2nd-4th parts), ascending colon, descending colon