Oesophagus
The oesophagus (about 10") is the first part of the digestive tract
proper and shares its distinctive structure. Basic tissue layers of the
gut are
1. mucosa. Innermost, moist lining membrane. Epithelium (friction resistant
stratified squamous in oesophagus, simple beyond) plus a little connective
tissue and smooth muscle.
2. submucosa. Soft connective tissue layer, blood vessels, nerves, lymphatics
3. muscularis externa. Typically circular inner layer, longitudinal outer
layer of smooth muscle
4. serosal fluid producing single layer.