THE DIGESTIVE SYSTEM

The human body is made up of countless millions of cells. Food is needed to build up new cells and replace parts that are damaged or worn out so that the body can grow. Food is also needed as fuel to provide energy for each cell, so that it can carry out its work properly.
However, the food that we take into our mouth must be changed into substances that can be carried in the blood to the places where they are needed. This process is called digestion.
The first digestive process takes place in the mouth. Some of the food, bread, rice and meat, for example is broken up into small pieces by the action of the teeth, and is mixed with saliva, a juice secreted by glands in the mouth. Saliva is the first of the digestive juices which the food meets on its way through the digestive system. These juices contain enzymes which help break down the food into particles that can be absorbed by the blood. The enzyme in saliva is responsible for breaking down carbohydrates.
From the mouth, food passes through the esophagus, into the stomach. Here the digestive juices made by the cells in the stomach wall play their part. The food is mixed with the juices for several hours, and when it is very nearly liuid, it is squeezed, through into the small intestine. Here more digestive juices get to work. Some are poured out by the lining of the intestine itself, some by a gland called the pancreas, and others by the organ known as liver. All the time the muscular walls of the intestine are squeezing, mixing and moving the food onwards.
In a few hours there is nothing left of the original bread, rice, meat or vegetables, but a mixture of all the chemical building blocks they were made of. These are small enough for the cells of the intestine to deal with. The intestine has many thousands of microscopic branch projections from its walls called “villi”.
By now the original foodstuffs have been changed into acids. These are soon absorbed by the villi and passed into the blood stream. What is left is waste matter, which is expelled from the anus.
The digestive system works best when a person enjoys his food, and the people with whom he is eating. Eating too fast, or during an argument, may cause pain in the stomach. This is called indigestion. It is therefore important to eat the right kind of food and to eat it in the right way.