Final answer:
The innermost layer of the esophagus is the mucosa, protected by the epithelium and supported by the lamina propria. Below the mucosa is the submucosa, which connects to the muscularis. The most superficial layer is the adventitia, not the innermost.
Step-by-step explanation:
The innermost layer of the esophagus is known as the mucosa. It is the layer directly in contact with the food we ingest and plays a critical role in the passage of food to the stomach. The mucosa is a mucous membrane comprised of non-keratinized, stratified squamous epithelium, along with basal and parabasal cells, that offers protection against erosion from food particles. Beneath this epithelial layer is the lamina propria, a layer of connective tissue that supports the epithelium and contains mucus-secreting glands. A thin layer of muscle known as the muscularis mucosae is also part of the mucosa.
Just below the mucosa is the submucosa, a layer of dense connective tissue that connects the mucosa to the underlying muscularis externa. It contains important structures such as blood and lymphatic vessels, submucosal glands, and the submucosal plexus of nerves. Contrary to the initial query, the most superficial layer is the adventitia, which is composed of loose connective tissue and lacks the visceral peritoneum that is found in the stomach and intestines.