GI for usmle

  1. which structures are retroperitoneal?
    • Duodenum (2,3,4)
    • Ascending colon
    • Descending colon
    • Kidney and ureters
    • Pancreas (except tail)
    • aorta
    • IVC
    • Adrenal glands
    • rectum
  2. Falciform ligament
    connects what?
    contains which structures?
    derivative of ?
    • connects liver to anterior abdominal wall
    • contains ligamentum teres
    • derivative of fetal umbilical VEIN
  3. hepatoduodenal ligament
    • liver to duodenum
    • contains portal triad (hep artery, portal vein, common bile duct)
    • connects greater and lesser ommentum
    • put your finger in the omental foramen and press on this to control bleeding
  4. gastrohepatic
    • connects liver to lesser curvature of stomach
    • contains gastric arteries
    • separates right greater and lesser sacs
  5. gastrocolic ligament
    • connects greater curvature of stomach to transverse colon
    • contains gastroepiploic arteries
    • is part of the greater omentum
  6. gastrosplenic ligament
    • connects greater curvature of stomach to the spleen
    • contains short gastrics
    • separates left greater and lesser sacs
  7. splenorenal
    • connects the spleen to posterior abdominal wall
    • contains splenic artery and vein
  8. Layers of the gut wall
    • 1. Mucosa
    • - epithelium (stratified squamous at the ends -esophagus and anus and simple columnar in the middle)
    • - lamina propria
    • - muscularis mucosae (smooth muscle)
    • 2. Submucosa
    • includes Meissner's plexus (submucosal plexus)
    • 3.Muscularis propria - the muscle is smooth muscle but in upper 1/3 of esophagus its skeletal
    • - inner circular layer of muscle
    • - Auerbach's plexus (myenteric plexus)
    • - outer longitudinal layer of muscle
    • 4. Serosa/adventitia
  9. Esophagus histo
    stratified squamous epithelium
  10. Stomach histo
    • gastric glands
    • parietal cells are pink
    • chief cells are blue
  11. Small intestine Histo
    • Villi and micro villi are greater duodenum>jejunum> ileum
    • duodenum - Brunnner's glands (submucosal) and crypts of Lieberkuhn
    • Jejunum - goblet cells (most in SI); plicae circularis and crypts of lieberkuhn
    • Ileum - peyer's patches (lamina propria, submucosa), plicae circularis (proximal), and crypts of Lieberkuhn
  12. Colon histo
    (dif from SI)
    Crypts no villi
  13. Foregut and blood supply and nerve
    • Stomach -> proximal duodenum
    • liver, gallbladder, pancreus, spleen

    • Celiac artery
    • Vagus Nerve
    • T12/L1 level
  14. Midgut and blood supply
    Distal duodenum --> proximal 2/3 of transverse colon

    • superior mesenteric artery
    • vagus nerve
    • L1
  15. Hindgut and its supply
    • Distal 1/3 of transverse colon to upper part of rectum
    • splenic flexure in watershed region

    • IMA
    • Pelvic - parasympathetic innervation (NOT vagus)
    • L3 vertebral level
  16. What are the nerve plexuses in GI tract? Where are they? What do they do?
    Myenteric (Auerbach's) - located b/w the outer longitudinal muscle layer and the inner circular muscle layer; coordinates Mobility of the entire wall

    Submucosal (Meissner's) - located in the submucosa (b/w mucosa and muscularis layers); regulates local secretions
  17. Where do we see varices in portal hypertension? (also which vessels are compensating)
    Esophagus (esophageal varices because blood from left gastric vein (portal)--> esophageal vein )

    Umbilicus (caput medusae because blood from paraumbilical veins (portal) --> umbilical veins)

    Rectum (internal hemorrhoids because blood from superior rectal veins (portal) --> middle and inferior rectal veins)
  18. What shunts could you use to relieve portal hypertension?
    1. Portocaval shunt - b/w splenic (portal) and left renal vein

    2. Connect portal vein to IVC
  19. Pectinate line
    where hind gut meets ectoderm
  20. Hemorrhoids above and below pecitnate
    above - internal, not painful, sign of portal htn

    below - external, painful
  21. cancer above and below pectinate
    • above - adenocarcinoma
    • below - squamous cell carcinoma
  22. Arterial supply and venous drainage above the pectinate line
    arterial supply - superior rectal artery (branch of inferior mesenteric artery)

    venous drainage - superior rectal vein --> inferior mesenteric vein --> portal system
  23. Arterial supply and venous drainage below the pectinate line
    arterial supply - inferior rectal artery from internal pudendal artery

    venous drainage - inferior rectal --> internal pudendal --> internal illiac --> IVC
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GI for usmle
GI stuff