Submucosa of esophagus

The submucosa of oesophagus is a layer of dense irregular connective tissue located between the mucosa and the muscularis externa. It provides structural support to the esophageal wall while allowing considerable distensibility during the passage of a food bolus. The loose arrangement of connective tissue permits the mucosa to form the characteristic longitudinal folds seen in the empty esophagus.

Histology of esophageal submucosa

The submucosa contains numerous blood vessels, lymphatic vessels, and autonomic nerve fibres, which supply the oesophageal wall.

• Embedded within it is the submucosal (Meissner's) plexus, a component of the enteric nervous system that helps regulate glandular secretion and local blood flow.

• The submucosa also contains the oesophageal glands proper, which are compound tubulo-alveolar glands that secrete mucus that lubricates the lumen and facilitates the passage of food while protecting the mucosa from mechanical injury.

Clinical correlate

• The rich submucosal venous plexus is of particular importance. At the lower end of the oesophagus, these veins communicate with both the portal and systemic venous systems, forming a site of portosystemic anastomosis. In patients with portal hypertension, these veins may become dilated, producing oesophageal varices, which can rupture and cause lifethreatening upper gastrointestinal haemorrhage.

• The extensive lymphatic channels within the submucosa of esophagus also contribute to the longitudinal spread of oesophageal carcinoma.