Mucosa

The mucosa of the oesophagus is thrown into folds at rest; when distended by food boluses, the folds disappear as the wall flattens. The layers of the mucosa are, from inside to outermost:

• mucosa:
  • non-keratinizing stratified squamous epithelium
  • at gastro-oesophageal junction, merges with simple columnar epithelium of stomach
• connective tissue: forms papillae which project into lumen
• muscularis mucosae:
  • increases in thickness from proximal to distal
  • contains:
    • smooth muscle bundles that increase in number to the gastro-oesophageal junction
    • mucus-secreting oesophageal glands which open by a duct onto the mucosa
    • lymphoid follicles