Gastrointestinal - Embryo, Anatomy, Blood Supply

eesohbel's version from 2015-07-30 21:13


Question Answer
foregutpharynx to duodenum
midgutduodenum to proximal 2/3 of tranverse colon
hindgutdistal 1/3 of transverse colon to anal canal above pectinate line
Gastroschisisextrusion of abdominal contents, not covered
Omphaloceleextrusion of abdominal contents, covered by peritoneum
Failure of rostral fold closuresternal defects
Failure of lateral fold closureomphalocele, gastroschisis
Failure of caudal fold closurebladder exstrophy
Duodenal atresia (failure to recanalize)Trisomy 21
Jejunal, ileal, colonic atresiad/t vascular accident (apple peel atresia)
Esophageal atresia with distal tracheoesophageal fistulamost common cause of EA (85%)
Drooling, choking, vomiting with first feeding
TEF allows air into the stomach → visible on CXR
failure to pass NG tube into stomach
H-type esophageal atresiaPure TEF
Pure EA does not show...gas in abdomen on CXR
Describe the anatomy of the MC type of esophageal fistula with distal TEFblind upper esophagus with the lower esophagus attached to the trachea
Pyloric stenosispalpable "olive" mass in epigastric region
nonbilious projectile vomiting at ~2 weeks of age
Acid base disordercongenital pyloric stenosis hypokalemic hypochloremic metabolic alkalosis
treatment for pyloric stenosissurgery (mc condition requiring surgery in first month of life)
Pancreas derived fromforegut
Ventral pancreatic bud →pancreatic head, main pancreatic duct, uncinate process
Dorsal pancreatic bud →body, tail, isthmus, accessory pancreatic duct
Pancreatic divisumpancreatic ductal systems remain separate with the accessory duct draining the majority of the pancreas. Because the ventral part of the pancreas has the major duct.
Annular pancreasventral pancreatic bud abnormally encircles 2nd part of duodenum
forms a ring of pancreatic tissue that may cause duodenal narrowing
Pancreas divisumventral and dorsal parts fail to fuse at 8 weeks
Spleen arises from where?mesentary of stomach
BUT it's supplied by the foregut (celiac artery)
Retroperitoneal structures (mnemonic)SAD PUCKER
Suprarenal gland (adrenal)
Aorta and IVC
Duodenum (2nd and 3rd parts only)
Pancreas (except tail)
Colon (descending and ascending only)
Esophagus (lower 2/3rds)
Rectum (lower 2/3rds)
Infant feeding difficulties in first few days of lifeannular pancreas, TE fistula and duodenal atresia
Infant feeding difficulties if first few weeks of lifepyloric stenosis
Billous vomitting few days after birthmalrotation of the gut
billous vomitting right at birthintestinal atresia, meconium ileus, hirschsprung
non billous vomitting in normal term malepyloric stenosis
any GI problem in low birth weight or premieNEC

GI Ligaments NOT HY

Question Answer
Falciform connectsliver to anterior abdominal wall
Gastrohepatic connectsliver to lesser curvature of stomach
Gastrocolic connectsgreater curvature and transverse colon
Gastrosplenic connectsgreater curvature and spleen
hepatoduodenal connectsliver to duodenum
Splenorenal connectsSpleen to posterior abdominal wall
Falciform containsligamentum teres hepatis
(derivative of fetal umbilical vein)
Hepatoduodenal containsPortal triad: hepatic artery, portal vein, common bile duct
Gastrohepatic containsgastric arteries
Gastrocolic containsgastroepiploic arteries
Gastrosplenic containsshort gastrics, left gastroepiploic vessels
Splenorenal containsSplenic artery and vein, tail of pancreas
Falciform is derived from...ventral mesentery
Pringle maneuverhepatoduodenal ligament may be compressed between thumb and index finger to control bleeding
Which ligaments connect the greater and lesser sacs?Gastrohepatic - on the right
Gastrosplenic - on the left
Which ligament is part of the greater omentum?Gastrocolic

Digestive tract

Question Answer
Layers of gut wall, from inside → outMSMS
Muscularis externa
Serosa/adventitia (when retroperitoneal)
Mucosal layer contains which layers?epithelium - absorption
lamina propria - support
muscularis mucosa - motility
Which layer contains Meissner's plexus?Submucosa, (submucosal nerve plexus)
Which layer contains Auerbach's plexus?Muscularis externa, (myenteric nerve plexus)
Fn of myenteric (Auerbach) plexus?controls muscle contractions
Fn of submucosal (Meisner's) plexus?controls secretory activity
Ulcerextends into submucisa
erosionstays in mucosa only
Function of Auerbach's plexuscontrols motility

Digestive tract histology

Question Answer
Histology of esophagusnonkeratinized stratified squamous epithelium
Histology of stomachgastric glands
Histology of DuodenumVilli and microvilli (↑ absorptive surface)
Brunner's glands (submucosa)
crypts of Lieberkuhn
Histology of jejunumPlicae circulares and crypts of Lieberkuhn
Histology of ileumPeyer's patches (lamina propria, submucosa)
plicae circulares (proximal ileum)
crypts of Lieberkuhn
Largest # of goblet cells in small intestine
Histology of coloncrypts but no villi
numerous goblet cells

Blood supply

Question Answer
Structures supplied by celiac trunk (foregut)lower esophagus to proximal duodenum
spleen (mesoderm)
Structures supplied by SMA (midgut)Distal duodenum to proximal 2/3 of transverse colon (splenic flexure) (midgut)
Structures supplied by IMA (hindgut)Distal 1/3 of transverse colon to upper portion of rectum
splenic flexure is a watershed region (hindgut)
splenic flexurewatershed area between SMA (midgut) and IMA (hindgut)
Branches of celiac trunkcommon hepatic, splenic, left gastric → main blood supply of the stomach
Stong anastomoses of circulation around stomachleft and right gastroepiploics
left and right gastrics
Poor anastomoses around stomachshort gastrics (if splenic artery is blocked)
SMA syndromeoccurs when transverse portion of duodenum is entrapped between SMA and aorta, causing intestinal obstruction.
Branches of celiac trunkhepatic, splenic and left gastric
Proximal Lesser Curvature of the stomachleft gastric
distal lesser curvatureright gastric
proximal greater curvatureleft gastroepiploic
distal greater curvatureright gastroepiploic
proximal greater curvature above splenic arteryshort gastric
artery supplies proximal 1/3 of ureterrenal artery
fundus of the stomachshort gastric, branches of the splenic artery
pylorus and proximal part of doudenumgastroduodenal artery


Question Answer
Blood supply/drainage above pectinate lineA: superior rectal artery (IMA)
V: superior rectal vein → inferior mesenteric vein → portal system
Blood supply/drainage below pectinate lineA: inf rectal artery (branch of internal pudendal artery)
V: inf rectal vein → internal pudendal vein → internal iliac vein → IVC
Hemorrhoids above pectinate lineinternal (not painful). Hemorrhoids always drained by vein.
Hemorrhoids below pectinate lineexternal (painful). Hemorrhoids always drained by vein.
Cancer above pectinate lineadenocarcinoma
Cancer below pectinate linesquamous cell carcinoma
Lymphatic drainage above pectinate linesinternal iliac nodes
Lymphatic drainage below pectinate linessuperficial inguinal nodes
Anal fissuretear in anal mucosa below Pectinate line

Portosystemic Anastomoses

Question Answer Column 3
esophagusesophageal varicesleft gastric to esophageal
umbillicuscaput medusaparaumbilical to superficial and inferior epigastric
rectuminternal hemorroidssuperior rectal to middle and inferior rectal


Question Answer
portal vein to IVCpre-hepatic
portal tributary (splenic vein, SMV or IMV) to left renal veinpre-hepatic
portal vein to hepaticpost-hepatic
risk of TIPShepatic encephalopathy and hyperammoniemia
to cure hepatic encephalopathylactulose and neomycin

Liver/biliary system NOT HY

Question Answer
Zone 1 of liverperiportal zone
affected 1st by viral hepatitis
ingested toxins
Zone 2 of liverintermediate zone
affected by yellow fever
Zone 3 of liverpericentral vein (centrilobular) zone:
-affected 1st by ischemia
-contains P450 system
-most sensitive to metabolic toxins
-site of alcoholic hepatitis
Flow of blood through liverZone 1 → Zone 3
Flow of bile through liverZone 3 → Zone 1
Portal triadBile duct, branch of portal vein, branch of hepatic artery
Ampulla of Vaterwhere main pancreatic duct and common bile duct both drain into duodenum
Sphincter of Oddicontrols bile/pancreatic juice flow out of the ampulla of Vater
Relationship of cystic duct, common bile duct, and common hepatic ductcystic duct + common hepatic duct = common bile duct
tumors in head of pancreas block what ductcommon bile duct
gall stones that reach confluence of common bile and pancreatic duct causedouble duct sign cholangitis and pancreatitis

Femoral/inguinal region

Question Answer
Organization of structures at femoral triangleLateral→Medial
NAVEL: nerve, artery, vein, empty space, lymphatics
Femoral sheathcontains femoral vein, artery, and deep inguinal lymph nodes - NOT the femoral n.
Located 3-4 cm below the inguinal ligament
Direct herniathrough abdominal wall. through external inguinal ring only. covered only by spermatic external fascia. in old men
Order of muscles from deep to superficialRectus abdominis, pyramidalis, transversus abdominis, internal oblique, aponeurosis of external oblique muscle
Indirect herniaprotrusion through internal inguinal ring, external (superficial) inguinal ring, into scrotum. occurs in infants because of failure of processus vaginalis to close. all three layers of spermatic fascia
Femoral herniaProtrudes below inguinal ligament through femoral canal below and lateral to pubic tubercle and medial to the femoral vein
More common in women
Leading cause of bowel incarceration
Diaphragmatic herniaMost commonly a hiatal hernia: stomach herniates upwards through esophageal hiatus of the diaphragm
Sliding hiatal herniaMC diaphragmatic hernia
GE junction is displaced superiorly - "hourglass stomach"
Paraesophageal herniaGE junction is normal.
Fundus protrudes into the thorax
MDs dont LIeMedial to inferior epigastric artery= Direct hernia; Lateral to inferior epigastric artery=Indirect hernia
Weakness of the tranversalis fasciaDirect Hernia
Persistent processus vaginalis and failure of internal inguinal ring to closeindirect hernia

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