The process of digestion is a very complex operation which incorporates
many organs and various enzymes to complete. Of coarse,the first step in
digestion is when one sits down to a tempting meal, and the mouth begins
to water in anticipation of an impending culinary delight such as a homemade
PB&J sandwich. As the teeth grind each savory morsel, they are mixed
with an enzyme commonly known as spit (saliva), which acts as a catalyst
to break down carbohydrates and other complex materials.
After chewing and swallowing, the food passes down the throat, and through the pharynx. It is now just a mushy mass, and looks very little like the gooey sandwich that it started out as. The pharynx connects to the esophagus where undulating contractions, called peristalsis, carry the food to the stomach.
Food is taken to the stomach for more processing and is combined with various other enzymes and digestive chemicals to break down the food particles into smaller pieces that the body can use. Simple molecules such as water, salt, simple sugars, and alcohol are capable of being absorbed directly into the wall of the stomach. However, other more complex foods must go through more vigorous digestion. The thick stomach walls generate contractions which in turn creates a churning motion. The peanut butter, jelly, and bread are now undergoing the trauma of a roller coaster ride, and at the same time are being bombarded and mixed with strong chemicals like hydrochrolic acid, and enzymes such as pepsin, that assists in the breakdown of these foods.
After sufficient decomposition of the food has occurred, it is usually in a slurry colloid state called chyme. The chyme is pushed in to the first part of the twenty foot long small intestine. In the C-shaped duodenum muscular contractions move the chyme along as various chemicals work on them, similar to a conveyer belt motion.
Organs such as the pancreas, liver, and gallbladder work as reinforcements to the stomach and they "nuke" the chyme even more with powerful enzymes.
The villi, finger like projections that increase surface area in the small intestine, carry most of the nutrients to the bloodstream through tiny blood vessels, and so the delightful afternoon snack just consumed has served its purpose; it provided tasteful pleasure and useful energy.
Heartburn, acid indigestion, and ulcers are all common ailments that
plague people who enjoy delighting in high calorie, fat loaded, rich treats.
Unfortunately, when a large plate of hamburgers and french fries, or something
of the like, are served up, few think of the painful repercussions that
may follow. But, as the pang of heartburn sets in a large bottle of the
"Pink Stuff" ( Peptobismal )
makes its first appearance.
Totally disregarding the recommended dosage of two spoonfuls, most down the whole bottle and sigh hoping for fast relief from the painful "inferno" in their middle chest. Heartburn actually has nothing the do with the heart, but is a result of acidic digestive fluids that are pushed up into the esophagus, causing irritation. The "Pink Stuff" is now slowly beginning its descent through the esophagus and the stomach, coating these surfaces with protection and reducing painful irritation and damage from acids. Constant penetration of the gooey mucus stomach lining causes the delicate cells of the stomach or duodenum to be damaged or destroyed, resulting in painful sores known as ulcers.
When stomach pains get unbearable, or heartburn and acid indegestion
are at their worst, who are you going to call?........... The Gastrointestinal
Specialist. The two basic methods of abdomen examination are the use of
a stethoscope and percusion for listening to sounds, and palpation which
is feeling the organs such as the stomach, intestines, and liver with the
fingers and palms of the hands.
For more complicated ailments, an endoscopy may be performed. An endoscope, a tubelike instrument that is inserted down the gastrointestinal tract, has a camera attached to the end which assists the doctor in getting a firsthand view of the digestive organs. Due to the fact that soft organs such as the intestine and stomach do not show up on normal X-rays, a GI series may be performed in order to get a clearer picture of these organs. To have the organs show up on this type of X-ray, the patient is given a mixture of barium sulfate and water. This substance has the unique property of clinging to the walls of the intestines and showing up white on the X-ray. A fluroscope is another instrument that aids the doctor in observing the organs. It lets them see the organs in motion.
Images copyright PhotoDisc, Inc., 1996.
Images copyright T/Maker Company, 1996.
New Book of Knowledge, 1987. Grolier Inc.