The Human Digestion Summary Human Digestive SummaryOur digestion system goes through three phases when digesting food.
Digestion begins the moment food enters the mouth. It gets chewed by our teeth and we are able to swallow and soften food with the aid of our tongue, salivary glands and pharynx. The salivary glands initiates the process of digestion; the food transforms to bolus and goes into the esophagus working down its way towards the stomach where it is mixed into semi-liquid called cyme. The cyme reaches the small intestine which measures about 20 feet. Here the liver, pancreas and gallbladder add secretions and absorb nutrients needed by the body. The celiac phase is the first phase that begins prior to eating. Here the body prepares for digestion. The smell or sight of food stimulates the brain which releases a chemical into the stomach.
If you ever had that feeling of watery mouth when you see or smell food, this is part of the celiac phase. Our body also lowers our glucose levels to prepare for the added sugars we are about to ingest. If we skip or prolong eating we began to feel lightheaded and hungry because our body initiated the celiac phase assuming we were going to fuel our body. The gastric phase takes about three to four hours beginning the moment enters the mouth. Once the food inters the stomach; secretions are released to aid food process. The stomach stretches to allow room for the food and a sphincter closes between the pathway of the esophagus and stomach. Individuals who suffer from heartburn have a (loose sphincter) and the secretion or acid released by the stomach for digestion seeps through the sphincter and goes up the esophagus causing the burning sensation known as heartburn.
The stomach releases more gastric juices such as acetylcholine, histamine, and hydrochloric acid. These acids break down the food and prepares for absorption. The intestinal phase begins when the partially digested food enters the small intestine (duodenum). There is another sphincter between the stomach and the small intestine. The sphincters aids in blocking or preventing more food to pass through the small intestine. Small muscular movements allow food to be digested and aid transporting and absorbing nutrients.
Some foods can be in the duodenum for up to ten hours. Undigested food is moved to the large intestine and through the colon where it expels the feces. Some undigested waste can sit in the colon for hours or even days. ReferencesDietary sources of minerals. (1997) Consumer Reports on health, 9(11), 124Livestrong. The Stages of Food Digestion.
Nov 5, 2010 Staci McGonigal http://www. livestrong. com/article/297746-the-stages-of-food-digestion/
