My Science School

Everything you eat has to be chopped up and broken down before the nutrients or goodness in it can be taken into your blood and used by your body cells to make energy. This takes place in your digestive system or gut. The food leaves your stomach a little at a time and goes into your small intestine. This is where most of the digestion takes place by adding digestive chemicals and absorbing the digested chemicals and absorbing the digested nutrients into the body. The lining of the intestine is folded into millions of tiny fingers called villi. Undigested food continues its journey on to the large intestine where excess water and minerals are extracted from the leftover food.

Fact File: How much energy do we use? Sitting or lying: 43-72 cals per hour Walking: 144-216 cals per hour Running: 432-575 cals per hour

 

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The major function of saliva is to help in the process of digestion. It keeps the mouth moist and comfortable when we eat and helps to moisten dry food, allowing it to be chewed and swallowed more easily. The mucus in saliva coats the bolus (or chewed food) and acts as a lubricant to help us to swallow.

The enzyme ptyalin which is found in saliva begins the first stage of digestion. It begins to break down starchy food into simpler sugars. Saliva also allows us to taste our food and drink. Each day we all usually produce about 1.7 litres (3 pints) of saliva.

Fact File: The four main tastes are sweet, salt, bitter and sour, and you can taste them with different parts of your tongue. You can check where the four tastes are by dabbing it with a little salt, sugar, coffee grounds (bitter) and lemon juice (sour).

 

Picture Credit : Google