Flashcards in 101b GI Structure Deck (33)
What masses form the intracembryonic coelom?
lateral plate and cardiogenic mesoderm - hollow out to form a U-shaped tube
what embryonic structures separate the pleural and peritoneal cavities in early development?
what are the 4 primordia for the adult diaphragm?
septum transversum (central tendon)
mesentery of esophagus (diaphragm crura)
muscles from the body wall
At what level does the septum transversum/diaphragm form in the embryo? Nerve supply?
C3,4,5 - with cervical somites
Diaphragmatic hernia - description, types
abdominal contents into thorax; can occur in infants from failure of pleuroperitoneal membrane
types - sliding hiatal AND paraesophageal
sliding hiatal hernia
stomach slides through diaphragm opening for esophagus which displaces GE junction up
GE junction is normal but stomach fundus protrudes through esophageal opening with it's own thin layer of peritoneum
-congenital umbilical hernia of the midgut
-midgut fails to retreat back into abdomen during development
-covered by peritoneum
-body wall defect
-can be in thorax, abdomen, or pelvis
-not covered by peritoneum/organs are bathed in amniotic fluid
midline divisions of the abdomen (top to bottom)
flank divisions of the abdomen (top to bottom)
what ribs cover the spleen
what is the embryonic origin of GI organs?
splanchnopleuere (endoderm + mesoderm)
differentiate between parenchyma and stroma of an organ - location, origin
parenchyma = epithelial cells; endoderm
stroma = connective tissue framework; mesoderm
Both from splanchnopleure
foregut - artery supply, parasympathetic innervation, vertebral level, structures supplied
parasym nerve: vagus
vertebral level: T12/L1
structures: stomach --> proximal dueodenum; liver, gallbladder, pancreas, spleen
midgut - artery supply, parasympathetic innervation, vertebral level, structures supplied
parasym nerve: vagus
vertebral level: L1
structures: distal dueodenum to proximal 2/3 of transverse colon
hindgut - artery supply, parasympathetic innervation, vertebral level, structures supplied
parasym nerve: pelvic
vertebral level: L3
structures: distal 1/3 of transverse colon --> upper portion of rectum
where do arteries supplying GI structures branch from the abdominal aorta; name arteries top to bottom and vertebral level
celiac trunk - T12
SMA - L1
IMA - L3
name the SMA branches for the midgut (top to bottom)
middle colic (MC)
right colic (RC)
name the IMA branches for the hindgut (top to bottom)
left colic (LC)
superior rectal (SR)
name the branches of the celiac trunk and what direction they come off (patient perspective)
1) splenic artery - left
2) left gastric artery - top
3) common hepatic - right
what branch of the celiac trunk comes off to the left; what does it supply?
splenic artery - left; spleen + greater curve of stomach (short gastric arteries and left gastroepiploic)
what branch of the celiac trunk comes off to the top? what does it supply?
left gastric artery - top; lesser curve of stomach
what branch of the celiac trunk comes off to the right? what does it supply?
common hepatic - right; liver (hepatic proper + right gastric for lesser curve of stomach) + greater curve of stomach (gastroduodenal artery --> right gastroepiploic artery)
Where do presynaptic parasympathetics synapse for the GI tract?
-Myenteric (auerbach's) plexus - smooth muscle contraction in muscularis externa layer
-Submucosal (meissner's) plexus - glandular secretion and muscularis mucosa
spinal cord segments for visceral sensory innervation of the gut
T7-9 stomach (7 letters in stomach)
L1 left colic flexure
L5 sigmoid colon
3 anastomosis sites for venous portal-caval (portal vein first) and signs of portal obstruction/hypertension
1) left gastric-esophageal veins (esophageal varices)
2) para-umbilical vein - superficial epigastric veins (caput medussa on ab wall)
3) superior rectal veins - internal iliacs (hemorrhoids)
pancreas is derived from what?
2 buds - ventral and dorsal
what does the ventral pancreas bud become?
part of pancreatic head and the uncinate process
main pancreatic duct
what does the dorsal pancreas become?
body, tail, accessory pancreatic duct
what is an annular pancreas
ventral bud encircles duodenum and causes narrowing
what does the common bile duct (cystic duct from gall bladder + common hepatic duct from liver) lead to?
main pancreatic duct from the ventral bud