AP BIOLOGY

Detailed explanation-1: -In the stomach several mucosal defence mechanisms protect the stomach against hydrochloric acid and noxious agents. The pre-epithelial protection is made up by the mucus-bicarbonate barrier. Mucus and bicarbonate, secreted by mucus cells, create a pH gradient maintaining the epithelial cell surface at near neutral pH.

Detailed explanation-2: -The gastric mucosa is a layer of mucous membrane found in the stomach. This lining is found on the inner surface of the stomach, along with the glands and gastric pits. It is always covered in a layer of thick mucus secreted by columnar epithelial and glandular cells.

Detailed explanation-3: -The gastric mucosa is the mucous membrane layer of the stomach, which contains the glands and the gastric pits. In humans, it is about 1 mm thick, and its surface is smooth, soft, and velvety. It consists of simple columnar epithelium, lamina propria, and the muscularis mucosae.