Gastric mucosa

The mucosa is studded with millions of gastric pits, which the gastric glands empty into. In humans, it is about one millimetre thick, and its surface is smooth, and soft. It consists of simple secretory columnar epithelium, an underlying supportive layer of loose connective tissue called the lamina propria, and the muscularis mucosae, a thin layer of muscle that separates the mucosa from the underlying submucosa. The gastric mucosa serves as a gastric barrier, reinforced by tight junctions between the epithelial cells.

Three types of cell in the mucosa secrete mucus. Mucus cells in the pyloric glands produce a large amount of thin mucus. mucous neck cells produce mucus in the parietal glands. Surface mucous cells (foveolar cells), cover the entire mucosa between the gastric pits and into their upper parts, the mucus produced here is viscid, and alkaline.

Description

The gastric mucosa is the mucous membrane layer that lines the entire stomach. In its fresh state, it is pink at the pyloric end, and red or reddish-brown over the rest of its surface. In infancy it is of a brighter hue, the vascular redness being more marked.

It is thin at the cardiac extremity, but thicker toward the pylorus. During the contracted state of the stomach it is thrown into numerous folds or rugae, which, for the most part, have a longitudinal direction. They are most marked along the greater curvature, and toward the pyloric end, and are entirely obliterated when the stomach is stretched by a meal.

Viewed under a microscope, the inner surface of the mucous membrane presents a peculiar honeycomb appearance from being covered with funnel-like polygonal or hexagonal depressions which vary from 0.12 to 0.25 mm. in diameter. These are the ducts of the gastric glands, at the bottom of each may be seen one or more minute openings of the gland tubes. Gastric glands are simple or branched tubular glands that emerge on the deeper part of the gastric pits, and outlined by the folds of the mucosa.