ANATOMY

Detailed explanation-1: -Webs are thin ridges of tissue that protrude into the esophageal lumen from the surrounding esophageal wall and narrow the lumen. They may involve the entire wall of the esophagus (360 degrees) or only part of it.

Detailed explanation-2: -The adventitia is an external fibrous layer that covers the esophagus, connecting it with neighboring structures. It is composed of loose connective tissue and contains small vessels, lymphatic channels, and nerve fibers.

Detailed explanation-3: -The esophageal lining is protected by a stratified squamous epithelium. Because this epithelium is normally not exposed to dryness or to abrasion, it is non-keratinized. Scattered submucosal mucous glands provide lubrication. A well-developed muscularis provides peristaltic propulsion of food.

Detailed explanation-4: -The esophagus contains four layers-the mucosa, submucosa, muscularis, and tunica adventitia. The mucosa is made up of stratified squamous epithelium containing numerous mucous glands.