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Science Y6 – Marvellous Me – lesson 14 – information on digestive system

The Small Intestine

The small intestine is a long tube that is about 3-4 cm around and if
you stretched it out it would be about 6-7 metres long. The small
intestine has the important job of breaking down the food mixture
so your body can absorb all the nutrients it needs from food -

vitamins, minerals, proteins, carbohydrates, and fats.

The small intestine can't break down food for its nutrients by itself
- it gets help from three other parts of the digestive system. These
parts are the pancreas, the liver, and the gall bladder. They are not
part of the digestive tract itself, but they help out by sending

different juices to the small intestine.

It takes about three hours for the food to become very thin and watery. Lining the small intestine
are millions of fingers called villi. These absorb the chemicals that we need from the food into the
body and pass through the wall of the small intestine and into the blood. So now the eaten apple
can really get used by your body. The food that cannot be digested passes into the large
intestine. The End!

Not all that we eat can be digested.
The large intestine is fatter than the small intestine. It is
about 8 cm around, and like the small intestine it is packed
into the body, and if it were stretched out it would be 1.5
metres long.

Even though almost all the nutrients from the food you eat
has been absorbed in the small intestine, there will still be
parts of the food that your body can't use. This leftover
waste moves into the large intestine to begin its long journey
out of your body.

On its way, it goes into the colon, the part of the large intestine where most of the water that is left
in the liquid mix is absorbed into the blood. As the water leaves the mix, the waste that's left gets
harder and harder as it keeps moving along, until it becomes a solid.
When this solid waste reaches the end of the large intestine, it's been there for anywhere from 10
hours up to several days! The amount of time that the waste spends in the large intestine depends

on the kind of food that was eaten and how a person's body works.

The solid waste stays here until you are ready to go to the toilet.

The End of the Journey
By this point in the digestive journey everything your body needs from the food you eat has been
removed, and what's left is solid waste called faeces. This waste is removed from your body when
you go to the toilet. http://www.uen.org/utahlink/tours/tourFames.cgi?tour_id=13125

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