Digestive_System

DIGESTIVE SYSTEM The digestive system is a very complex system involving many components. The first phase is the mouth and throat. During this phase the food is chewed by the teeth and is pushed to the back of the throat past the salivary glands. The food is now called the bolus since it has been mixed with saliva from the salivary glands. The bolus then goes down the throat through the pharynx and into the esophagus. The epiglottis is a flap located at the top of the esophagus that keeps the food from going into the lungs. This phase lasts only minutes. The next digestive phase is the stomach. Once the bolus travels through the esophagus into the stomach it mixes with semiliquid mass that is called chyme. During this phase the pancreas, liver and gallbladder, located close to the stomach, add secretions to aid in the digestive process. This phase usually lasts about two to six hours. Then, the stomach empties the chyme into the small intestine; this starts the final phase. This last phase is the intestines phase. The small intestine is about twenty feet in length and it usually lasts from three to five hours. The chyme that is not absorbed into the small intestine as nutrients for the body is then passed into the large intestine. Once through the large intestine the waste is passed through the colon where additional absorption of vitamins and water occur. The large intestine are about five feet in length and it takes the chime up to twenty-four hours to pass through. Once the food you have eaten has passed through all these phases the waste that is not absorbed into the body is then excreted through the rectum as feces. (http://corptrain.phoenix.edu/axia/sci241/sci241-digestivetract.html)