Physiology III Structure of the Gut

Tunica mucosa- tunica submucosa- tunica muscularis- serosa (adventitia in esophagus)

Epithelium- lamina propria- lamina muscularis

Lamina muscularis- circular muscle- longitudinal muscle

Longitudinal muscle- circular muscle- myenteric plexus (Auerbach's): contration/ relaxation of smooth muscle

Layer of connective tissue that may contain glands

Submucosal plexus (Meissner's): secretions of digestive system

Exist in the wall of the digestive tube either as specialized enterocytes of as secretory cells in the mucosa or submucosa

Exist outside the wall of the digestive tube but their secretions enter the digestive tube

• Epithelial Goblet Cells ( not true examples)
• Mucosal crypt cells
• Mucosal gastric glands
• Submucosal Brunner's glands
• Submucosal mucin-secreting cells

• Salivary Acinar and Ductal Cells
• Pancreatic Acinar and Ductal Cells
• Hepatic parenchymal Cells and Ductal cholangeocytes

• Gastric Glands: fundic and pyloric region of stomach
• Crypts of Lieberkuhn in the SI and LI

• Mucin-secreting esophagus glands
• Brunner's glands: bicarbonate-secreting located in proximal duodenum

mucin-secreting cells that are distributed as single cells in the epithelial layer throughout the SI and LI of gut

Empty into oral cavity

duodenal papilla in duodenum

• Gut-associated lymphoid tissue and mucosa-associated lymphoid tissue.
• MALT emmbedded in walls of the airway and in the digestive tube
• GALT the innate immune system of the digestive tract

• Accumulation of lymphocytes or lymph follicles in the ileum, appendix and anus.
• Extend from the lamina propria to the submucosa