Page 12 - LN-CH-16

These contractions of muscles in the small intestine allows the further churning and
kneading of the chyme and finally pushing it into the large intestine.
The respective digestive juices from the liver (bile), pancreas (pancreatic juice) and
srtiall intestine (intestinal juices) are released into the small intestine to bring out the
further chemical simplification of food. The , pancreatic juice from the pancreas and
the bile from the liver are released through the hepato-pancreatic duct.
Enzymes from Pancreas
The pancreatic juice secreted from the pancreas contains the various inactive
enzymes.
These are as follows
(a) trypsinogen (b) chymotrypsinogen
(c) procarboxypeptidases (d) amylases (e) lipases (f) nucleases
Trypsinogen is activated by an enzyme enterokinase secreted by intestinal mucosa
into active trypsin which in turn activates the other enzymes of pancreatic juice.

* The proteins, proteases and peptones (partially hydrolysed form of proteins)
present in the chyme (reaching the intestine) are acted upon by the proteolytic
enzymes of pancreatic juice. These are given below as

* Carbohydrates in the chyme are hydrolysed by pancreatic amylase into
disaccharides.

* Nucleases in the pancreatic juice acts on nucleic acids to form nucleotides and
nucleosides.

Enzymes from Liver
The bile secreted from the liver is released into duodenum of small intestine. Bile
contains the bile pigments, i.e., bilurubin and biliverdin, bile salts, cholesterol and
phospholipids.
Thus, fats are broken down into di and monoglycerides by the action of lipases.

Note:
* Bile does not contain any enzymes as gastric juice. It helps in emulsifying fats, i.e.,
in breakdown of fats into very small micelles which are kept suspended in an
aqueous medium.
* The process of emulsification is basically carried out by the salts of bile. This