biology question?

Question

when the food moves from the stomach into the small intestine , the ph levels changes from acidic to alkaline?
this is because?? why??

Answer 1

Most hydrolysis of macromolecules occur in the small intestine. It is more than 6 meters in length. Accessory Organs (Pancreas, Liver, and Gall Bladder), add digestive enzymes, juices and hormones into the small intestine. As the acid chyme enters the duodenum (first 25 cm of the small intestine) a hormone called SECRETIN is released from the intestinal walls to siginal the pancreas to release a bicarbonate solution which neutralizes the acid.
The hormone CHOLECYSTOKININ (CCK), is released from the intestinal cells causing the gall bladder to release bile. It also causes the pancreas to release its digestive enzymes. The hormone ENTEROGESTRONE is also secreted to slow down peristalsis. Protein Digestion: Trypsin and Chymotrypsin are enzymes that break bonds next to specific amino acids. Carboxypeptidase splits off one amino acid at a time.
This enzyme works on the end with the free carboxyl group. Aminopeptidase works in the opposite direction. All the above enzymes are secreted in an inactive form. They are activated by the hormone ENTEROKINASE. Fat Digestion: Bile emulsifies fat. This creates a larger surface area for the enzyme lipase to digest it. Carbohydrate Digestion: Disaccharide digestion is under the control of the enzymes maltase, lactase, sucrase.

Answer 2

In the stomach, the digestion of protein is done by pepsin-HCl. The stomach content has a pH of 1-2. In the intestine, the protein is digested by trypsin which has a pH optimum of 7-8. Sodium bicarbonate is produced in the intestine to neutralize the acid as the food enters the intestine.