Structure/Morphology
The mucosa of the stomach is the innermost layer that lines the lumen. It’s composed of two regions, the epithelial layer and the lamina propria.
The epithelial layer is the layer that lines the lumen. It’s composed of a surface epithelium and involutions called gastric pits, or folds. The gastric pits contain stem cells that replace the cells of the surface epithelium. They also contain the secretory cells of the stomach which are typically found deeper in the pits. These cells include parietal cells, chief cells, mucous cells, and neuroendocrine cells. The distribution of secretory cells varies by region such that the parietal and chief cells are primarily found in the body and fundus, while endocrine and mucous cells are found in the pylorus as well.
The lamina propria is a loose connective tissue found below the epithelium.
In an empty stomach, the mucosa and submucosal layers are folded in on themselves. This allows for them to unfold during food intake when the stomach needs to expand.
Key Features/Anatomical Relations
The mucosa of the stomach is the innermost layer that lines the lumen of the stomach. It consists of the epithelial layer together with the lamina propria and muscularis mucosa. The submucosa lies outside the mucosa.
Function
The mucosa of the stomach is the layer containing secretory cells that protects the stomach from acid, digests food, and autoregulates the process of digestion in the stomach. Specifically:
- mucous cells secrete mucous and bicarbonate to protect the epithelial lining from acidic damage;
- parietal cells secrete hydrochloric acid to sterilize ingested material and help break down proteins. They also produce intrinsic factor, which is necessary for the absorption of vitamin B12 in the small intestine;
- chief cells product the zymogen pepsinogen, which is converted to pepsin and digests protein;
- neuroendocrine cells produce hormones such as histamine and gastrin (Standring, 2016).
References
Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41 edn.: Elsevier Limited.
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Gastric Mucosa
The gastric mucosa is a flat surface that contains multiple invaginations or gastric units.
