GIT

• CONGENITAL ANOMALIES

  1. Imperforate Anus
  2. Meckel Diverticulum
  3. Hirschsprung Disease
• Imperforate Anus

  • most common form of congenital intestinal atresia.
• Imperforate Anus

  • due to a failure of the cloacal diaphragm to involute
• Meckel Diverticulum

  • Most common true diverticulum
• Meckel Diverticulum

  • in the Ileum
• True diverticulum – blind outpouching of the alimentary tract that communicates with the lumen and includes all three layers of the bowel wall.
• Meckel Diverticulum

  Ectopic pancreatic or gastric tissue may also be present
• Meckel Diverticulum

  • occurs as a result of failed involution of the vitelline duct, which connects the lumen of the developing gut to the yolk sac.
• Meckel Diverticulum Rule of 2s

  • Occur in approximately 2% of the population
  • Generally present within 2 feet (60 cm) of the ileocecal valve
  • Approximately 2 inches (5 cm) long
  • Twice as common in males
  • Most often symptomatic by age 2 (only approximately 4% are ever symptomatic)
• Hirschsprung Disease

  • “congenital aganglionic megacolon”
• Hirschsprung Disease

  • Results when the normal migration of neural crest cells from cecum to rectum is arrested prematurely or when the ganglion cells undergo premature death
• Hirschsprung Disease

  • Lacks both the Meissner submucosal and the Auerbach myenteric plexus (“aganglionosis”)
• Hirschsprung Disease

  • Point of rupture occurs most frequently near the cecum.
• • Intraoperative frozen-section analysis is commonly used to confirm the presence of ganglion cells at the anastomotic margin
• • Ganglion cells can be identified using IHC stains for acetylcholinesterase
• Mucosa

  • Epithelium
  • Lamina propria
  • Muscularis mucosae
• • Submucosa – loose collagenous CT
  • Submucosal plexus (Meissner)
• Muscularis propria

  • Inner circular
  • Outer longitudinal
  • Inner oblique – in the stomach only
  • Myenteric plexus (Auerbach)
• Adventitia - serosa
• GIT Layers

  • Mucosa
  • Submucosa
  • Muscularis propria
  • Adventitia / serosa
• Arrange the following layers: Adventitia, Submucosa, Mucosa, Muscularis Propria.

  Mucosa, Submucosa, Muscularis Propria, Adventitia