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Introduction:

The digestive tract is a tube, a digestive tube. It is called a tube because it takes the shape of a long, hollow tube. It starts in the mouth and ends at the anus. But it is not a simple, uniform tube; it is made up of many different parts, each with its own name, such as, the mouth, oesophagus, stomach, duodenum, small intestine, large intestine, rectum and anus. 
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The digestive tract is attributed to digestion because it breaks down, that is, it deconstructs, the food that we eat &ndash; in a process called digestion &ndash; extracting the nutrients that the cells need from the food. Hence the cells do not eat xima, or oranges, or tomatoes; the digestive system breaks down the xima, the orange and the tomato, taking from these foods the nutrients, proteins, carbohydrates, fats, vitamins, minerals and fibres &ndash; that are important for energy and development of the body. The digestive tract absorbs these nutrients and sends them into the bloodstream to feed our cells, all of cells, the eye cells, the bones, the muscles, and so on. What we eliminate in the form of faeces, are the remains of non-digested food, it is &ldquo;waste&rdquo;. 
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There are other organs that participate in the digestive process even though they are outside the digestive tract, and these include the kidney, gall bladder and the pancreas. These organs produce enzymes, which are sent into the digestive tract to facilitate the digestive process. In simple terms, digestion happens like this:
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	Digestion begins in the mouth. Through the action of the teeth (chewing), the tongue and saliva, the foods are transformed into bolus. Digestion is a set of transformations that foods undergo in the organs of the digestive tract until they are reduced to small, simple particles.
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	How is the bolus transformed? The bolus passes from the mouth to the oesophagus, through the pharynx. Pushed down by the muscular contractions of the oesophagus wall, the bolus moves down towards the stomach. This passage is called swallowing. In the stomach, the bolus is subjected to the action of gastric juices and muscular contractions from the wall of this organ until it becomes chyme.
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	How is the chyme transformed? The chyme moves through the stomach to the duodenum in the small intestine. Waves of muscular contractions in the intestinal wall move the chyme and subject it to the action of bile (produced by the liver), pancreatic juices (produced by the pancreas) and intestinal juices (produced by the intestinal glands), breaking it down even further.
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	What happens to the chyme next? Once they have been digested, foods are reduced to simple nutritional substances, which the chyme is made from. These are absorbed into the bloodstream and transported to all the cells in the body. The passage of nutritional substances from the chyme into the bloodstream is called digestive absorption, which essentially happens through the tiny villi lining the inner wall of the small intestine. &nbsp;&nbsp;
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	When the nutritional substances reach the cells, they become part of that cell, in a process known as assimilation. Undigested food that has not been absorbed passes through into the large intestine and forms faeces, which is expelled through the rectum and anus.
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Our digestive system may create problems if we the food we eat is not balanced or we eat foods that are harmful to the digestive system. You may well ask how? Sometimes, we eat things that damage the normal functioning of the digestive system. For example, alcohol inhibits the action of one of the enzymes that works to stop acids from destroying the stomach lining. When this enzyme is inhibited, the acid can make contact with the stomach wall and cause gastritis, and some sufferers begin to say &ldquo;I have wounds in my stomach&rdquo;. People who eat a diet that lack a sufficient amount of fibres often get constipation, which can be very harmful to our overall health, because the waste that should leave our body as faeces, stays too long in our intestines. People that drink too little water or get too little exercise can also easily get constipation. 
 
This is why you must also learn about the care that needs to be taken to maintain the digestive tract.

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