Session 1 Overview

• GI tract organs?

  • Mouth
  • Pharynx
  • Oesophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Rectum
  • Anus
• Accessory digestive organs?

  • Tongue
  • Salivary glands
  • Liver
  • Pancreas
  • Gall bladder
• McBurney's point?

  • 1/3rd of the way along the line from ASIS to the umbilicus
  • common surface projection of appendix
• Gut tube is suspended from posterior abdominal wall by sheets of tissues which carries blood vessels, nerves, and lymphatics to gut - mesenteries
• Intraperitoneal Structures?

  • Stomach
  • Jejunum
  • Ileum
  • Cecum & Appendix
  • Transverse Colon
  • Sigmoid Colon
  • Liver
  • Spleen
• Retroperitoneal Structures?

  • Suprarenal (Adrenal) Glands
  • AbdominalAorta/IVC
  • Duodenum
  • Pancreas (except tail)
  • Ureters
  • Colon (Ascending and descending)
  • Kidneys
  • Esophagus
  • Rectum
• Mesenteries are double folds of peritoneal tissues.
• Peritonitis - Inflammation and infection of the peritoneum Commonly results from:

  • Burst appendix
  • Penetrating wound
  • Perforated duodenal ulcer
• Peritoneal adhesions - Damage to the peritoneum due to infection, surgery or injury

  Inflammation and repair → fibrous scar tissue

  Abnormal attachments between peritoneal surfaces
• Ascites – fluid in peritoneal cavity between visceral and parietal peritoneum
• 3 major trunks of arterial supply of gut?

  • Celiac trunk (foregut)
  • superior mesenteric artery (midgut)
  • Inferior mesenteric artery (hindgut)
• The celiac trunk divides into?

  • Left gastric artery
  • Splenic artery
  • Common hepatic artery
• The common hepatic artery divides into:

  • The hepatic artery proper
  • gastroduodenal artery
• Nutcracker Syndrome

  • Aneurysm of SMA
  • Obstruction of Duodenum
  • Compression of Left Renal Vein
  • Resection of Ligament of Treitz
• Varicocoele - enlargement of the pampiniform plexuses of the scrotum
• Venous Routes of the Gut?

  • Inferior mesenteric vein
  • Superior mesenteric vein
  • Splenic vein

  *Union of Splenic vein + SMV -> portal vein
• Lymphatics of the gut?

  • Inferior mesenteric nodes
  • Superior mesenteric nodes
  • Celiac nodes
• The celiac nodes drain into the cisterna chyli (as chyle) -> thoracic duct -> bloodstream via subclavian veins
• Nerves of the Gut Viscera?

  • Intrinsic - enteric nervous system
  • Extrinsic - Autonomic nervous system
• Enteric nervous system in the gut?

  • self-sufficient network of sensory and motor neurons
  • controls contraction and relaxation of intestinal smooth muscle
  • regulates gastric secretion
  • regulates blood flow
• Parasympathetic stimulation of the gut?

  • Rest and digest
  • increases muscle tone and peristalsis
  • relaxes the sphincters
  • increase acid and pepsin production
• Sympathetic stimulation of the gut?

  • decreases muscle tone and peristalsis
  • contracts the sphincters
  • decreases acid and pepsin production
• Pancreatic Cancer - Often invades pancreatic head.
• 3 divisions of oesophagus?

  • Cervical
  • Thorcaic
  • Abdominal
• Physiological constrictions of oesophagus?

  • Cervical: Cricopharyngeus muscle
  • Thoracic: Broncho-aortic arch
  • Abdominal: Oesophageal hiatus of the diaphragm
• At rest, lower oesophaeal sphincter prevents reflux of gastric contents into oesophagus,
• Oesophageal Herniae - Part of stomach protrudes into chest through diaphragm.
• Sliding Hiatal Hernia

  • Failure of the phrenico-oesophageal ligament
  • Not a medical emergency
  • Displaced lower esophageal sphincter.
  • Heartburn, dysphagia
• Rolling (Para-oesophageal) Hiatal Hernia

  • Medical emergency
  • Fundus of stomach can become necrotic
  • Diffuse Pain
  • LESS common
• Oesophageal blood supply?

  Upper third: inferior thyroid artery

  Middle third: thoracic aorta

  Lower third: left gastric artery
• Oesophageal venous drainage?

  Upper third: inferior thyroid veins to brachiocephalic veins

  Middle third: azygos vein → SVC (SYSTEMIC)

  Lower third: Azygos vein → SVC →heart (SYSTEMIC) AND Left gastric vein → portal vein → liver (PORTAL)
• 4 regions of stomach?

  • Fundus
  • Cardia
  • Body
  • Pyloric region
• Gastric ulcers associated with H. pylori bacteria.
• Blood supply to the stomach?

  Anastomoses along greater and lesser curvature from branches of

  • Celiac trunk
  • right and left gastric arteries
  • right and left gastro-omental arteries
  • short gastric arteries
• Blood supply to duodenum?

  Proximal: Branches of Celiac trunk

  Distal: SMA
• Parts of duodenum?

  1. Superior part: most duodenal ulcers occur here- Duodenal cap.
  2. Descending Part: Contains major and minor duodenal papillae (biliary and pancreatic juices enter here)
  3. Inferior Part: Crossed anteriorly by SMA and SMV
  4. Ascending Part: Ligament of Treitz (suspensory ligament of duodenum) attaches 4 th part to the diaphragm.
• ileocecal valve - prevents reflux of material back into the ileum.
• What distinguishes large intestine and small intestine?

  Distinguishing anatomical features

  • Taeniae coli
  • Haustrations
  • Appendices epiploica
• paracolic gutters?

  • Depressions formed between lateral margins of intestine and posterolateral abdominal walls
  • Relatively blood-free zone
  • Fluid/pus/infection can pass from one region of peritoneal cavity to another (important for spread of infection)
• Diverticulosis: multiple out-pocketings of mucosa of colon

  Common in sigmoid colon in middle aged/elderly → diverticulitis