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Small intestine and secretion

Anatori Sealife Comments 0 11th April 2019
The small intestine. What does stimulates the secretion of stomach juices?

The small intestine is approximately twenty-three feet or seven meters in length. It begins at the pyloric valve of the stomach ends at the ileocecal valve between the ilium and cecum. Besides, it has an average diameter of about one inch. Millions of fingerlike projections, also called villi, increase the inner porous surface area, where they are present throughout. Likewise do the plicae circulares, deep, circular folds in the intestine’s mucosa.

Peristalsis is a slow, wavelike muscular contraction that pushes chyme through the tube. Rhythmic segmentation involves circular muscle contractions at alternate points around the chyme. Thus, it helps mix the chyme and the intestinal juices. The pendular movement consists of the alternation of circular and longitudinal muscles contraction in the intestine, increasing the mixing of chyme and intestinal fluids.



Small intestine secretion

Most of the digestion and a majority of the absorption occurs in the small intestine. The pancreatic, liver, and intestinal secretions neutralize acid chyme from the stomach in the intestine. However, the pH of the intestine is continually increasing from the duodenum to the ileocecal valve.

Other hormones related to digestive activities are secretin, pancreatin, enterocrinin, and cholecystokinin. As a result, chyme entering the small intestine stimulates the secretion of these hormones.

Secretin and pancreatin stimulate the secretion of pancreatic juices, enterocrinin stimulates the secretion of digestive enzymes from the small intestine, and cholecystokinin promotes both the contraction of the gallbladder and the relaxation of the sphincter of Oddi. This sphincter controls the flow of bile and pancreatic juices from the common bile duct into the duodenum.



Trypsin

The exocrine secretions of the small intestine are digestive. Enterokinase activates pancreatic trypsinogen (inactive trypsin) to proceed with protein digestion. Meanwhile, the final breakdown of amino acid chains involves trypsin. Weak amylase promotes the breakdown of complex sugars into disaccharides. Maltase breaks down maltose into glucose.

Sucrase breaks down lactose into glucose and galactose. Further, Brunner’s Gland releases a final intestinal secretion. Also, a mucous secretion protects the intestinal lining from the acid chyme. Besides their digestive and protective qualities, the intestinal juices aid in transporting undigested material.