The pancreas is an organ that is 6-8 inches long and extends horizontally across the abdomen. It is part of
the digestive system and is a gland organ that produces insulin, having a key role in glucose control.
During digestion, partially digested food passes through the stomach to the small intestine where
secretions from the pancreas will mix with these foods. These secretions come from the exocrine tissues,
these tissues make up around 95% of the pancreas. Within these secretions contain several enzymes that
help the breakdown of food. The digestion of proteins happens with the help of the two enzymes within
the pancreas: trypsin and chymotrypsin. They act within the duodenum and help start the process of
breaking down proteins into individual amino acids. They are very similar but have a small number of
differences. The main difference is the amino acids that they select for – chymotrypsin is the enzyme that
selects the aromatic amino acids (tryptophan, phenylalanine, and tyrosine) and trypsin selects basic amino
acids (lysine and arginine). These amino acids are then absorbed into the bloodstream through the lining of
the small intestine.
The pancreas has an extremely important role in the Carbohydrase – Carbohydrases are produced in
secretion of fluids and bicarbonate ions (HCO3-). both salivary glands and the pancreas. They are a
These ions help neutralise the acidity of the gastric set of enzymes that cause 5 types of reactions
contents entering the duodenum. This process when turning carbohydrates into simple sugars.
happens within the pancreatic duct cells, these cells Because complex sugars (called polysaccharides) =
\ the pancreatic duct and are responsible for the
line such as starch are often insoluble, carbohydrase
bicarbonate-rich substance it produces. are needed for the hydrolysis of polysaccharides
to be broken down into simple sugars (called
The pancreatic duct connects the pancreas to the monosaccharides) with the help of a water
common bile duct to help supply pancreatic juice. substance, which is why carbohydrase are often
Pancreatic juice is made of various enzymes: trypsin found within the pancreas and salivary glands. An
and chymotrypsin as mentioned before to break example of a carbohydrase is the conversion of
down proteins, amylase for the breakdown of Maltose (carbohydrate formed from starch by the
carbohydrates and lipase to break body fats down. amylase enzyme) is converted to glucose. This is
Pancreatic juice secretion is primarily regulated by done when maltase (enzyme) is the catalyst of the
the hormones within the duodenum walls: secretin hydrolysis chemical breakdown of maltose and
and cholecystokinin. The pancreatic juice is alkaline water to form glucose.
and enzyme rich. This process is the result of
bicarbonate originating from duct cells and enzymes Protease – Protease is an enzyme that increases
coming from acinar cells. When bicarbonate ions the rate of the breakdown of proteins into smaller
and chyme (a mix of partially digested food, water, polypeptides or amino acids. Protease also use
hydrochloric acid and digestive enzymes) mix, the hydrolysis within their chemical breakdowns. This
bicarbonate neutralises the low pH of the chyme happens when peptide bonds within proteins
which comes from the stomach, while the enzymes divide by hydrolysis. Several proteases within
break down lipids and carbs for absorption in the proteins are secreted into the lumen of the small
intestines. The juice is then secreted into the intestine
duodenum through duodenal papillae. Lipase – Lipase also use hydrolysis to increase the
breakdown rate of fats (lipids). Pancreatic lipases
are secreted outside of the cell where they are
able to process dietary lipids into forms that can
easily be absorbed and transported through the
body. They convert triglycerides that are found in
ingested oils into monoglycerides and fatty acids.
An example of lipase is when bile salts that are
secreted from the liver and stored in the
gallbladder are released into the duodenum. They
mix with the larger fat droplets, turning them into
small droplets. This increases the surface area of
the fat which allows the lipase to break the fat
apart more effectively into fatty acids.
Liver