1 - Abdominal Viscera

Question 1

Objectives: Know arrangement of adult abdominal viscera and understand their embryonic origins

Foregut Organs

Answer 1

• Esophagus
• Stomach
• Upper Duodenum
• Liver
• Gall Bladder
• Pancreas
• Blood Supply: Celiac Trunk

Question 2

Objectives: Know arrangement of adult abdominal viscera and understand their embryonic origins

Midgut Organs

Answer 2

• Lower Duodenum
• jejunum
• Ileum
• Cecum
• Appendix
• Asceding Colon
• Prox. 2/3 Transverse Colon
• Lower Pancrease
• Blood Supply: Superior Mesenteric Artery

Question 3

Objectives: Know arrangement of adult abdominal viscera and understand their embryonic origins

Hindgut Organs

Answer 3

• Distal 1/3 Transverse Colon
• Descending Colon
• Sigmoid Colon
• Superior Rectum
• Blood Supply: Inferior Mesenteric Artery

Question 4

Objectives: Know anatomy and subdivisions of the GI tract from esophagus through anal canal

Answer 4

• Esophagus - Esophageal hiatus of diaphragm, T10
• Stomach - Left Hypochondrial / Epigastric region, position variable
• Duodenum - Shortest part of small intestines; curves around pancrease; 5 parts
• Jejunum - Middle small intestine, large D, thick wall, infoldings, little fat
• Ileum - Ends at cecum; found in all abdominal quadrants, small, thin wall, few infoldings, more fat
• Cecum - lower right quadrant, intraperitoneal
• Appendix - usually retrocecal, deep to McBurney’s Point, intraperitoneal
• Ascending Colon - ascends to hepatic flexure, retroperitoneal, immoble
• Transverse Colon - ascends to splenic flexure, intraperitoneal, mobile
• Descending Colon - Descends from splenic flexure to sigmoid colon, rertoperitoneal, immobile
• Sigmoid Colon - b/t descending colon and rectum; intraperitoneal, mobile
• Rectum & Anal Canal - Fixed part of large intestine, continuous with anal canal

Question 5

Objectives: Identify features that distinguish different parts of the small intestine

Duodenume - Ducts?

Jejunum vs Ileum?

Retro vs Intra peritoneal?

Answer 5

• Duodenum - Partially Retroperitoneal
  
  • Receives Common Bile Duct and Main Pancreatic Duct via Hepatopancreatic Ampulla (of Vater)
  • Major Duodenal Papilla (of Vater) is small protrusion on internal duodenum where hepatopancreatic ampulla enters
  • Hepatopancreatic Sphincter (of Oddi) surrounds ampulla, regulates bile and pancreatic secretions
  • 4th Ascending Part - Secured by Suspensory Muscle of Duodenum (Ligament of Treitz)
• Jeunum - Intraperitoneal
  
  • ​Large D, Thick Walled
  • Few Arterial Arcades
  • Long, Few Vasa Recta, Large Windows
  • Little Fat
  • Many Infoldings
• Ileum - Intraperitoneal
  
  • ​Small D, Thin Walled
  • Many Artery Arcades
  • Short, Many Vasa Rectra, Small/None Windows
  • More Fat,
  • Few Infoldings

Question 6

Objectives: Identify features that distinguish the small from the large intestine

Large Intestine Features:

Teniae Coli

Haustra

Plicae Semilunares

Appendices Epiploicae

Answer 6

• Large Intestines:
  
  • Teniae Coli - 3x longitudinal muscle bands
  • Haustra - Sacculations of colon produced by teniae
  • Plicae Semilunares - Infoldings of intestinal wall between haustra
  • Appendices Epiploicae - Peitoneum-covered pouches of fat, attached in rows along teniae

Question 7

Objectives: Know key features of spleen, pancreas, liver and gall bladder

Answer 7

• Spleen - Large lymph organ; left hypochondrial region
  
  • Independent Embryonic Origin
• Pancrease - Digestive (exocrine) and endocrine organ; Epigastric / Left Hypochondrial Regions
  
  • Main Duct (Wirsung)
  • Accessory Duct (Santorini)
• Liver - Right hyopchondrial / Epigastric regions, four lobes
  
  • Coronary Ligament - R/L Triangular Ligaments
  • Falciform Ligament - Connect liviver to ant. abdominal wall; contains Ligamentum Teres Hepatis (round ligament)
• Gall Bladder - R. Upper Quadrant
  
  • Stores and concentrates bile
  • Cystohepatic Triangle (of Calot) = Surgical landmark

Question 8

Objectives: Understand routes and drainages of cystic-biliary ducts

R / L Hepatic Ducts

Common Hepatic Duct

Cystic Duct

Bile Duct

Main Pancreatic Duct

Hepatipancreatic Ampulla

Accessory Pancreatic Duct

Answer 8

• R / L Hepatic Ducts
  
  • Leave liver through Porta Hepatis
• Common Hepatic Duct
  
  • Formed by union of L/R Hepatic Duct
• Cystic Duct
  
  • Fills, drains gall bladder
• Bile Duct
  
  • Formed from union of Common Hepatic and Cystic Ducts; runs through head of pancreas
• Main Pancreatic Duct (from ventral pancreatic bud in development)
  
  • Joins bile duct to form Hepatopancreatic Ampulla
• Hepatpancreatic Ampulla
  
  • Enters duodenum @ Major Duodenal Papilla
  • Controlled by Circular Smooth Muscle (Hepatopancreatic Sphincter)
  • Can be impacted by gallstones
• Accessory Pancreatic Duct (from dorsal pancreatic bud in development)
  
  • Enters duodenum @ Minor Duodenal Papilla