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I
f we are what we eat, then what we are is
only as good as our digestion. When it goes awry, it generally
affects our total well-being. Whether it's mild nausea, a nasty
virus, or a chronic disorder such as irritable bowel syndrome,
a disorder of the digestive tract is usually impossible to
ignore. If the condition persists, it can undermine our total
health, eventually threatening our very lives.
How the Digestive System
Works
The gastrointestinal (GI) tract is a long
hollow tube stretching from the head to the end of the body,
including the mouth, pharynx, esophagus, stomach, small
intestine, and large intestine. The salivary glands, liver,
gallbladder, and pancreas are also important parts of this
far-reaching system.
The main purpose of the GI tract is to
break down carbohydrates, fats, and proteins into molecules
small enough to be absorbed through cell membranes. In that
way, it provides the cells with the necessary energy for life
and health.
Digestion begins in the mouth when food is
chewed and starch is broken down by ptyalin, an enzyme secreted
in saliva. Food then enters the stomach, where it is reduced to
tiny particles and further transformed by gastric juices. The
solid portion remains in the stomach for one to six hours until
it liquefies completely; liquid passes into the duodenum (small
intestine), where numerous enzymes produced by the pancreas,
along with bile from the liver, break it down further for
absorption. When it finally arrives in the large intestine, all
nutritional value has been spent, and the only remaining
process is the removal of water before final
elimination.
Every section of the GI tract is prone to
its own unique disorders--some merely annoying, others
potentially fatal. Fortunately, for all but a few we now have
simple treatments that will, at the very least, relieve the
symptoms.
Next:
Diseases of the Upper GI
Tract
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