The is a vital enzyme splitting starch into polysaccharides

The human body can be
simply seen as a machine which is entirely organised and sophisticated, that
lots of systems inside work together and help each other accomplish their works
efficiently. Each of the systems is made up of many organs and contributes to
body functioning in various ways. (Murbach et al., 2013) Digestive system which
help us to digest what we intake in every single days plays an important role
for our body. It is composed by several organs from mouth to large intestine.
Saliva and pancreas are 2 components of digestive system, they both contain
digestive juice for breaking large food bolus down to smaller portions that
make body easier to absorb nutrients and energy. Whereas, saliva and pancreas
also contributes to immune and endocrine systems respectively. (Taylor-Butler,
2008) Although
saliva are like the liquid to keep mouth be moist and the pancreas is only 6
inches long, (Taylor-Butler, 2008) their roles in body cannot be underestimated.
This article will attempt to explain the secrets under the saliva and pancreas,
including their roles in different systems and the importance of them for
bodily functions.

There are three main
parts of salivary glands in mouth to secret saliva which are the parotids,
submandibular gland and sublingual gland. Different part of glands secret
different components of saliva. Saliva helps to digest food in several
different ways. Firstly, lots of study shows that saliva is responsive to
digest food by the enzymes inside. Amylase which is mostly produced by parotids
is a vital enzyme splitting starch into polysaccharides in oral cavity. This is
the first step of digestion. Secondly, the mucus in saliva lubricate the food and
improve the efficiency during mastication as the food bolus can be moved and
swallowed more easily. Thirdly, the saliva is still useful when the food get
into the stomach. Although amylase would be inactivated by gastric juice, it
will take times to break up the food within stomach. So normally there is still
half an hour for saliva to continue its work. 
That is what saliva does for digestive system. It there is no saliva
existed, our mealtime will be an extremely uncomfortable experience. (Ligtenberg,
2014) Furthermore, saliva also
contribute to immune system. There are some kinds of antibodies in saliva that
produced by plasma B cells in salivary glands. The mucous layers with the
antibodies that line on the epithelial
cells protect the oral cavity from the antigens. It is also called the first
barrier of immune defense. The one of major enzyme in saliva is
lysosome, which is mostly produced by the serous demi lunes of the
submandibular glands. Lysosome can defense
some certain bacteria. An example is streptococci that it can be lysed by
lysosome. Another main enzyme, sialo peroxidase also gives a big help on
keeping the health of oral cavity. It catalyzes
the reaction of substance in mouth to make hypo thiocyanate which is highly
toxic to bacteria. Because of the antimicrobial properties in saliva,
Infections in mouth is barely observed even after a dental surgery. (Kaufmann,
Rouse and Sacks, 2011)

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The exocrine tissue of pancreas has a secretion
of pancreatic juice which is very important for digestive system. The juice is
conducted to the duodenum by the control of sphincters. The juice contain
different important kinds of the enzymes which are used to break down different
macromolecules. The enzymes are stored in zymogen granules contained in
pancreatic acinar cells. Amylase is also contained inside to break carbohydrate
as the function in saliva. The second important enzyme is lipase that is used
to break emulsification droplets of fats into mono-glycerol and fatty acid for
further absorption in small intestine. There are also some inactive enzymes
existed which are trypsin and chymotrypsin that are used to break the
polypeptide into amino acid. But trypsin firstly need to be activated from
trypsinogen by the intestine gland secretion. After that, the chymotrypsinogen
would be activated to be chymotrypsin by the trypsin. In addition, there are
also other types of enzymes to give a help on breaking down these
macromolecules such as protease. If there is no pancreatic juice existed, the
duodenum will have an overload operation if you don’t intake additional enzyme.
(Mellanby, 1926) On the other hand, the endocrine system of pancreas contribute
to the control of metabolism by the hormones secreted which are insulin and
glucagon. Glucagon and insulin are produced by alpha cells and beta cells in
the tail of pancreas respectively, and they are constantly affected by each
other when they are working during the regulation of blood level between two
meals. The worktime of them refers to the patterns from absorption state to
post-absorption state. When the nutrients have been absorbed from small
intestine into bloodstream, the sugar level of blood is increased which would
bring about the production of insulin in pancreas. The insulin then respond to
the concentration of glucose, amino acid and lipids in bloodstream that send
signals back them into cells.  The
glucagon is the opposite hormones to the insulin and is stimulated by
hypoglycaemia. It prevents a too low blood sugar level. Insulin and glucagon
regulated each other in order to balancing the blood level. The glucagon in the
people with diabetes is too high due to the lack of the insulin. (Scheen, 2005) Besides, there are still some other hormones
existed to assist the main two hormones for endocrine system. (Jefferson and
Cherrington, 2001)

In conclusion, saliva and pancreas both produce
digestive juice to break down food bolus. Meanwhile, saliva protect body
against bacteria and pancreas regulate blood level inside body. Except the key
roles of them
in the systems above, they still
have other contributions for body. For example, saliva protects soft and hard
palates against ulceration desiccation and helps keep the water balance in oral
cavity (Adams, 1974). Lots
of partnerships in body still has not been discovered, but what
can be assured is each systems inside cooperate with each other to build our
bodies. All of them are
necessary for bodily functions.