by Jeffrey Ware

Created on: December 02, 2008

The digestive system is responsible for the digestion of food for the purpose of supplying the body with the necessary nutrients and minerals need to sustain life. It is also responsible for excreting waste and toxins from the body. The digestive system is comprised of several organs each performing certain functions to complete the process.

Beginning with the mouth and teeth, the first stage of the digestive process begins with chewing food. The chewing process breaks food up into smaller pieces while stimulating salivary glands within the mouth. The salivary glands excrete a digestive enzyme that begins the chemical breakdown of the food. When chewing is complete the food is swallowed and enters the esophagus where muscles force the food down through the gastro-esophageal valve into the stomach. This valve prevents food and gastric enzymes from refluxing into back up the esophagus.

The stomach, a football size J shaped hollow organ, churns the foods while excreting gastric acids and digestive enzymes to further breakdown the food. The gastric acids also help kill any bacteria that may have been swallowed. The stomach consists of two layers, the outside layer, Serosa, contains the muscles and the inner layer, mucosal contains the glands. The stomach is expandable to accommodate the volume of food swallowed. Food will remain in the stomach until the food is a semi solid form. The food is then slowly passed through the Pyloris, a valve, into the duodenum.

The duodenum is the first part of the small intestines and is where the actual absorption of nutrients from the food begins. The duodenum is a hollow tube approximately 10 12 inches long. When food enters the Duodenum it is mixed with bile, a digestive enzyme that is produced in the liver and stored in the gall bladder. The bile enters the duodenum through a tube call the common bile duct through the ampoule of vater. A little further down the pancreas releases more digestive enzymes into the duodenum to mix with the food. Both bile and pancreatic enzymes are necessary for the body to absorb the nutrients and minerals from the food. When food leaves the duodenum it is in a liquid state and enters the second part of the small intestines called the jejunum.

The jejunum is also a hollow tube approximately eight feet in length. It is the second longest section of the small intestines. This is where the majority of absorption occurs. The jejunum consists of two layers. The inner most layer is lined with a membrane that

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