How the food is digested?

Posted on March 9, 2009

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There are some organs that involved in digestive system. They are mouth, esophagus, stomach, duodenum, small intestine, large intestine, rectum, and anus. There are liver and pancreas which produce enzymes to break the carbohydrates (amylum), proteins and vitamins -formed in polypeptides- to dipeptides or monopeptides.
Digestion begins in the mouth, when you chew and swallow, and is completed in the small intestine. The process of chewing in mouth is called mechanical process. Only the carbohydrate is processed in chemical process. The amylum is then breaks into maltose with the help of amylase. After chewing for some times, then the swallowing process begins.
The first major muscle movement occurs when food or liquid is swallowed. Although you are able to start swallowing by choice, once the swallow begins, it becomes involuntary and proceeds under the control of the nerves. Swallowed food is pushed into the esophagus, which connects the throat above with the stomach below. At the junction of the esophagus and stomach, there is a ringlike muscle, called the lower esophageal sphincter, closing the passage between the two organs. As food approaches the closed sphincter, the sphincter relaxes and allows the food to pass through to the stomach.
In the stomach, there are two kinds of digestive process; mechanical and chemical. The stomach has three mechanical tasks. First, it stores the swallowed food and liquid. To do this, the muscle of the upper part of the stomach relaxes to accept large volumes of swallowed material. The second job is to mix up the food, liquid, and digestive juice produced by the stomach. The lower part of the stomach mixes these materials by its muscle action. The third task of the stomach is to empty its contents slowly into the small intestine. There are many kinds of enzyme produced by the stomach, but the main purpose is to break the chemical chain into simpler chemical essence.
Finally, the digested nutrients are absorbed through the intestinal walls and transported throughout the body. The waste products of this process include undigested parts of the food, known as fiber, and older cells that have been shed from the mucosa. These materials are pushed into the colon, where they remain until the feces are expelled by a bowel movement.

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