Embryology of GI Tract

Question 1

what type of folding leads to the GI tract?

Answer 1

transvers

Question 2

what original developmental tissue does the GI tract bud from?

Answer 2

yolk sac

Question 3

a dorsal and ventral mesentery form during GI development…which of these mainly disappears?

Answer 3

ventral…except for the part that goes to the liver

Question 4

what two layers of tissue lead to the GI tract?

Answer 4

endo and mesoderm

Question 5

explain how the midgut forms during development

Answer 5

it herniates outward and the cranial end twists and turns and the caudal end does not

Question 6

the cranial end that herniates becomes what?

Answer 6

the small intestine

Question 7

the caudal end that herniated becomes what?

Answer 7

large intestine

Question 8

what is duodenal atresia? what type of vomiting is associated with it?

Answer 8

when the duodenum is either filled in with something or too narrow for food to pass….biilious vomiting

Question 9

what can be seen on X ray with duodenal atresia?

Answer 9

double bubble of stomach and duodenum

Question 10

what is congenital pylorci stenosis? what type of vomiting is associated with it?

Answer 10

pyloric wall hypertrophy so food cannot get into SI…leads to non bilious vomiting

Question 11

what is an umbilical hernia? how does this form?

Answer 11

small quantity of intestines coming out of umbilical cord but are covered by skin…

normal development as midgut returns from umbilical area in week 10 but herniates again later in development

Question 12

what is an omphalocele? how does it form?

Answer 12

midline protrusion of navel containing intestines

form because herniated midgut does not totally return to middle during development

Question 13

what is an omphalocele covered with?

Answer 13

peritoneum like sac

Question 14

what is gastroschisis? how does it form?

Answer 14

protrusion of intestines near midline but not at midline…

abdominal wall fails to close during development

Question 15

what is a gastroschisis covered by?

Answer 15

nothing

Question 16

what does meckels diverticulum form from?

Answer 16

a remnant of vitelline duct from the herniation of the midgut in development

Question 17

where is meckels diverticulum located? how long is it? when do you see symptoms?

Answer 17

2 feet from ileocecal junction
2 inches
2 years of age

Question 18

what is the common symptom seen with meckels diverticulum?

Answer 18

bleeding

Question 19

what is Hirschprungs disease?

Answer 19

absence of innervation to the wall of distal GI

Question 20

what causes Hirschprungs disease?

Answer 20

neural crest cells in the distal GI portion do not migrate correctly

Question 21

name two things that are findings in Hirschprungs disease

Answer 21

a congenital megacolon and a failure to pass meconium

Question 22

what leads to the development of the liver?

Answer 22

ventral mesentery

Question 23

remaining ventral mesentery becomes what for the developed liver?

Answer 23

falciform ligament

Question 24

how many buds lead to the development of the pancreas? name them

Answer 24

ventral and dorsal pancreatic buds

Question 25

the ventral pancreatic bud arises with what an invagination that leads to what two other structures?

Answer 25

liver and gall bladder

Question 26

how do the ventral and dorsal pancreatic buds join?

Answer 26

the ventral bud rotates and joins the dorsal bud

Question 27

what does the ventral pancreatic bud become?

Answer 27

the head of the pancreas

Question 28

what does the dorsal pancreatic bud become?

Answer 28

part of the head and then the body and tail of the pancreas

Question 29

name the three portions of the pancreas

Answer 29

head body tail

Question 30

as other GI organs grow, what happens to the location of the pancreas?

Answer 30

it is pushed to a retroperitoneal position on the posterior body wall

Question 31

when starting development is the pancreas retro or intraperitoneal?

Answer 31

intraperitoneal