Bird, esophagus (LM, Low)

Structure List Lumen Epithelial layer Lamina propria Mucous glands Muscularis mucosa Inner muscularis externa Outer muscularis externa

AVIAN ESOPHAGUS. The esophagus of birds functions to move food from the pharynx into the rest of the digestive tract. It is lined by stratified squamous epithelium. Mucous glands are found in the lamina propria to help lubricate the food since birds have no teeth to break up food before swallowing. There are three layers of smooth muscle in the wall: the muscularis mucosa arranged longitudinally; the inner layer of the muscularis externa which is arranged circularly; the outer layer of the muscularis mucosa arranged longitudinally.