secretions of the Small intestine
The mucosa of the small intestine produces secretions that primarily
contain mucus, electrolytes, and water- Intestinal secretions lubricate
and protect the intestinal wall from the acidic chyme and the action of
digestive enzymes. They also keep the chyme in the small intestine in
a liquid form to facilitate the digestive process. The intestinal mucosa
produces most of the secretions that enter the small intestine, but the
secretions of the liver and the pancreas also enter the small intestine
and play essential roles in the process of digestion (see table 21.1).
The duodenal glands and goblet cells secrete large amounts of
mucus. This mucus protects the wall of the intestine from the irritating
 effects of acidic chyme and from the digestive enzymes that enter
the duodenum from the pancreas. The vagus nerve, secretin, and
chemical or tactile irritation of the duodenal mucosa stimulate secretion
 from the duodenal glands. Goblet cells produce mucus in reponse to the tactile and chemical stimulation of the mucosa.