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THE DIGESTIVE SYSTEM WHAT IT IS AND HOW IT WORKS All humans and almost all animals have a tube like digestive system. Each ones digestive tract is specially designed to break down the kinds of food it eats. Our bodies survive by food and water. The nutrients and energy we receive from food allow our bodies to repair itself. However, before food can do any of these things, it has to be changed into a form or substance the body can absorb into the bloodstream. In order for this process to take place, food must be digested with our digestive tract system. The digestive tract is often referred to as the gastrointestinal tract. The digestive tract of the adult is approximately 30 to 35 feet long. Everything we eat has to be broken down into absorbable nutrients while traveling through this tract, which is why it takes so long for food to fully digest. Food is broken down into microscopic particles, or sometimes referred to as molecules, and is separated by digestive organs into nutrients and waste. The nutrients are then passed through channels on the digestive systems intestinal wall to the bloodstream, which then distributes them to nourish cells throughout the body. The digestive system consists of different individual organs, beginning with the alimentary canal and ends with the anus. The actual digestion process starts at the mouth, where amylase, which is found in saliva, starts to break down carbohydrates in food, before it even leaves the mouth. The food then passes down the throat and moves down through the esophagus. After this process, it continues down the digestive tract into the stomach, which is located in the middle of the abdomen. The stomach will then store the food while all the time, mixing it with acids and enzymes, breaking it into much smaller digestible pieces. When it is empty, the adults stomach has a volume of only 1/5 of a cup, but can expand to hold more than 8 cups of food after a full meal has been eaten. The stomach empties into the small intestine, which will digest the food chemically so the body is able to absorb it into the bloodstream. The liver, gallbladder and the pancreas all help with the aid of the digestion process, by producing enzymes and substances that travel by way of special ducts, directly into the small intestine.
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