The Epic Interactive Encyclopedia 1996/Epic Interactive Encyclopedia, The (1996)(Epic Marketing)[non-bootable].iso/d/digestion/infotext

Text File | 1992-09-02 | 3KB | 62 lines

Digestion is a very complicated process by
which food is broken down into its components
and absorbed by the body. Food is composed of
several basic groups, all of which are
digested slightly differently. The groups are
proteins, fats, carbohydrates (sugars and
starches), minerals (such as salt, calcium
and iron), roughage (also called fibre) and
water (which is very important). Water and
minerals are not digested at all, but are
absorbed unchanged. Fibre is not digestable,
and passes through the body. It is necessary,
however, as a bulking agent to make the bowel
work properly. Proteins are digested into
amino acids, fats are digested into fatty
acids, and carbohydrates are digested into
simple sugars. Most digestion happens by the
action of enzymes, which are special proteins
produced by the body. There are millions of
different enzymes, and they have a huge range
of functions. In the digestive system,
however, they act to break down food into its
component parts. Digestion begins in the
mouth, where food is ground up by the teeth
into a mushy paste. This is swallowed, and
passes down the oesophagus (the tube which
connects the mouth to the stomach) into the
stomach. The stomach is like a large bag, and
collects the food for the second part of
digestion. The stomach produces powerful
acid, which helps to destroy any harmful
germs which may have been swallowed in the
food, and helps the digestive process. In the
stomach, protein is digested by an enzyme
called pepsin. The stomach also churns the
food and mixes it efficiently. The food then
passes out of the stomach into a special area
of the small intestine, which is called the
duodenum. The pancreas is an organ which
pours out a mixture of enzymes into the
duodenum to further digest the food. The
three main enzymes produced by the pancreas
are trypsin, which also digests protein,
lipase, which digests fat, and amylase, which
digests carbohydrates. The gall-bladder also
secretes bile into the duodenum, which helps
to digest and absorb fats and fatty acids. As
the mixture passes along the small intestine,
amino acids, fatty acids and simple sugars
are absorbed by the walls of the intestine
and taken away by the bloodstream, where they
are processed by the liver and packaged up
for the rest of the body to use. Most of the
remaining water and minerals is absorbed by
the large intestine, and the fibre, together
with any remaining undigested food, passes
through to end up as faeces at the end of the
large intestine, where they are passed
through the anus.

Subject by: Dr Aidan M. O'Donnell