Embryology of GI Tract Flashcards
what type of folding leads to the GI tract?
transvers
what original developmental tissue does the GI tract bud from?
yolk sac
a dorsal and ventral mesentery form during GI development…which of these mainly disappears?
ventral…except for the part that goes to the liver
what two layers of tissue lead to the GI tract?
endo and mesoderm
explain how the midgut forms during development
it herniates outward and the cranial end twists and turns and the caudal end does not
the cranial end that herniates becomes what?
the small intestine
the caudal end that herniated becomes what?
large intestine
what is duodenal atresia? what type of vomiting is associated with it?
when the duodenum is either filled in with something or too narrow for food to pass….biilious vomiting
what can be seen on X ray with duodenal atresia?
double bubble of stomach and duodenum
what is congenital pylorci stenosis? what type of vomiting is associated with it?
pyloric wall hypertrophy so food cannot get into SI…leads to non bilious vomiting
what is an umbilical hernia? how does this form?
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
what is an omphalocele? how does it form?
midline protrusion of navel containing intestines
form because herniated midgut does not totally return to middle during development
what is an omphalocele covered with?
peritoneum like sac
what is gastroschisis? how does it form?
protrusion of intestines near midline but not at midline…
abdominal wall fails to close during development
what is a gastroschisis covered by?
nothing
what does meckels diverticulum form from?
a remnant of vitelline duct from the herniation of the midgut in development
where is meckels diverticulum located? how long is it? when do you see symptoms?
2 feet from ileocecal junction
2 inches
2 years of age
what is the common symptom seen with meckels diverticulum?
bleeding
what is Hirschprungs disease?
absence of innervation to the wall of distal GI
what causes Hirschprungs disease?
neural crest cells in the distal GI portion do not migrate correctly
name two things that are findings in Hirschprungs disease
a congenital megacolon and a failure to pass meconium
what leads to the development of the liver?
ventral mesentery
remaining ventral mesentery becomes what for the developed liver?
falciform ligament
how many buds lead to the development of the pancreas? name them
ventral and dorsal pancreatic buds
the ventral pancreatic bud arises with what an invagination that leads to what two other structures?
liver and gall bladder
how do the ventral and dorsal pancreatic buds join?
the ventral bud rotates and joins the dorsal bud
what does the ventral pancreatic bud become?
the head of the pancreas
what does the dorsal pancreatic bud become?
part of the head and then the body and tail of the pancreas
name the three portions of the pancreas
head body tail
as other GI organs grow, what happens to the location of the pancreas?
it is pushed to a retroperitoneal position on the posterior body wall
when starting development is the pancreas retro or intraperitoneal?
intraperitoneal
