HUMAN NUTRITION

Detailed explanation-1: -The mucosa has glands that secrete mucus to keep the lining moist and well lubricated to ease the passage of food. Upper and lower esophageal sphincters control the movement of food into and out of the esophagus.

Detailed explanation-2: -The reasons for this are that the esophagus lacks a mucus layer and its surface cells do not secrete bicarbonate ions. The lack of a surface mucus layer is somewhat surprising given that the esophagus is bathed by swallowed saliva and secretions from its submucosal glands.

Detailed explanation-3: -The esophagus is about 8 inches long, and is lined by moist pink tissue called mucosa.

Detailed explanation-4: -Mucus is a protective substance that is secreted from multiple areas in the body such as the mouth, sinuses, throat, lungs, and stomach. Mucus is produced by the goblet cell of the gastrointestinal tract. It is a glycoprotein.