PRACTICAL ROADMAP DIGESTIVE SYSTEM WJ van der Spuy
LAYERS OF DIGESTIVE TRACT
• Mucosa – Lining Epithelium (glands derived) – Lamina Propria (connective tissue & lymphatic tissue) – Muscularis Mucosa (smooth muscle)
• Submucosa – (connective tissue, blood & lymphatic vessels, nerve plexus
& sometimes glands)
• Muscularis Externa – (inner circular & outer longitudinal smooth muscle)
• Adventitia / Serosa – (connective tissue / connective tissue & mesothelium)
Mucosa
Non-keratinised stratified squamous epithelium
Lamina propria
Muscularis mucosa
Lumen
Blood vessel
Lymphatic nodule in lamina
propria
Oesophageal submucosal gland
Blood vessels
Irregular dense connective tissue
Mucosa
Submucosa
Submucosa Note: Meissner’s plexus found in submucosa
Cystic duct of gland
Basophilic lymphoid tissue
Muscularis Externa
Submucosa
Muscularis externa Inner circular layer
Muscularis externa Outer longitudinal layer
Note: Upper 1/3 = skeletal m., Middle 1/3 = skeletal & smooth m., Lower 1/3 = smooth m. Note: Auerbach plexus found between m. layers
Mucosa
Mucosa
Lumen
Gastric pit lined by simple columnar epithelium
Muscularis mucosa
Submucosa
Lymphoid tissue of lamina propria
Fundic glands
Muscularis Externa
Submucosa
Muscularis externa with inner oblique, middle circular and outer longitudinal layers
Auerbach plexus
SMALL INTESTINE
• Slide 84 Duodenum – H&E stain
Mucosa Submucosa Muscularis Externa Adventitia & Serosa
Mucosa
Muscularis mucosa
Lamina propria extending into villi
Simple columnar epithelium with microvillus border
covering villus
Peyer’s patches in lamina propria
Glands
Goblet cells
Crypts of Lieberkϋhn opening between two villi
Villi
Brunner’s gland
Secretory units of Brunner’s glands
Columnar cells with apical microvilli
Muscularis Externa
Serosa
Submucosa
Muscularis externa inner circular layer
Muscularis externa outer longitudinal layer
Auerbach plexus
Mucosa
Mucosa
Simple columnar epithelium with apical microvilli
Goblet cells
Muscularis mucosa
Lamina propria
Submucosa