The digestive system is composed of a very long tube called the digestive tract and accessory organs that aid in digestive processes. Accessory digestive organs and structures include the teeth, salivary glands (produce saliva), the liver and the pancreas.
The process of digestion starts in the mouth. When we take in food, such as a piece of meat or bread, the teeth start to grind the food substance. The saliva produced by the salivary glands help make food easy to pass through the succeeding tract. In addition, enzymes—substances capable of increasing processes—present in the saliva start breakdown of food particles. For example, the salivary amylase is an enzyme that starts the breakdown of carbohydrates.
In the mouth, the food is formed into a mass of food particles called bolus.
The bolus then passes through the upper digestive tract into the stomach. Here, the food is further broken down into little pieces and stored for as long as 2 hours. The stomach then directs small amounts of its contents into the next tract—the small intestine.
Most of the digestion processes occur in the small intestine. It is where most of the nutrients are absorbed. Enzymes produced by the liver that aid in breaking down food particles also drain in the small intestine. Once most needed nutrients are absorbed, small intestine contents are pushed toward the large intestine.
In the large intestine, the substances are now called feces or stool. Here, stools are pushed toward the rectum where elimination of bowel is triggered. Some vitamins, ions and fluids are also absorbed in the large intestine. In addition, bacteria that are normally living in this area produce some B vitamins and vitamin K.
As the rectum is filled with feces, its wall is stretched and eventually triggers bowel elimination.
So there you go, the digestive processes. More information about the digestive system can be found on our digestive system page.
Source: Physiological background provided by the National Institute of Diabetes and Digestive and Kidney Diseases, available at.
Page Last Revised: August 2, 2012
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The process of digestion starts in the mouth. When we take in food, such as a piece of meat or bread, the teeth start to grind the food substance. The saliva produced by the salivary glands help make food easy to pass through the succeeding tract. In addition, enzymes—substances capable of increasing processes—present in the saliva start breakdown of food particles. For example, the salivary amylase is an enzyme that starts the breakdown of carbohydrates.
In the mouth, the food is formed into a mass of food particles called bolus.
The bolus then passes through the upper digestive tract into the stomach. Here, the food is further broken down into little pieces and stored for as long as 2 hours. The stomach then directs small amounts of its contents into the next tract—the small intestine.
Most of the digestion processes occur in the small intestine. It is where most of the nutrients are absorbed. Enzymes produced by the liver that aid in breaking down food particles also drain in the small intestine. Once most needed nutrients are absorbed, small intestine contents are pushed toward the large intestine.
In the large intestine, the substances are now called feces or stool. Here, stools are pushed toward the rectum where elimination of bowel is triggered. Some vitamins, ions and fluids are also absorbed in the large intestine. In addition, bacteria that are normally living in this area produce some B vitamins and vitamin K.
As the rectum is filled with feces, its wall is stretched and eventually triggers bowel elimination.
So there you go, the digestive processes. More information about the digestive system can be found on our digestive system page.
Source: Physiological background provided by the National Institute of Diabetes and Digestive and Kidney Diseases, available at
Page Last Revised: August 2, 2012
[Top of Page]
