If 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
