what organ secretes mucus
1 Specialized exocrine cells of the mucosa known as mucous cells secrete mucus into the lumen of the stomach and into the gastric pits. 2  This mucus spreads across the surface of the mucosa to coat the lining of the stomach with a thick, acid-and enzyme-resistant barrier. Specialized exocrine cells of the mucosa known as mucous cells secrete mucus into the lumen of the stomach and into the gastric pits. 2  This mucus spreads across the surface of the mucosa to coat the lining of the stomach with a thick, acid-and enzyme-resistant barrier.