Which component protects the stomach mucosa from acid and digestive enzymes?

Which component protects the stomach mucosa from acid and digestive enzymes?

• A. Mucus layer
• B. Muscularis externa
• C. Submucosa
• D. Serosa

Answer: (A)

The protective barrier is the mucus layer that lines the stomach. Secreted by surface mucous cells, this gel-like layer coats the epithelium and contains bicarbonate, which neutralizes acid right at the mucosal surface. That combination keeps the highly acidic environment and digestive enzymes from injuring the stomach lining, while also providing lubrication. The other layers of the stomach wall serve structural and motility roles—muscularis externa handles contractions, submucosa provides support and houses vessels and nerves, and serosa is the outer protective layer—but none of them directly shield the epithelium from acid and enzymes.

The protective barrier is the mucus layer that lines the stomach. Secreted by surface mucous cells, this gel-like layer coats the epithelium and contains bicarbonate, which neutralizes acid right at the mucosal surface. That combination keeps the highly acidic environment and digestive enzymes from injuring the stomach lining, while also providing lubrication. The other layers of the stomach wall serve structural and motility roles—muscularis externa handles contractions, submucosa provides support and houses vessels and nerves, and serosa is the outer protective layer—but none of them directly shield the epithelium from acid and enzymes.