SCIENCE CLASS5A

THE DIGESTIVE SYSTEM

What happens in our digestive system?

We prepared an experiment to see how food changes from the moment we eat it until we expel it.We wanted to show it to our friends from 5B.

We prepared a snack.

We prepared some food: some banana, some peas, and some bread.

We started by “eating” the food.

We mashed it with our teeth and mixed it with our tongue

(a wooden spoon).

We added saliva from salivary glands (some water from a bottle).

Then we “swallowed” it, and it travelled down the oesophagus to the stomach.

In the stomach we mixed the food with stomach acid and enzymes which started to digest the

proteins.

The food stayed in the stomach for 2-3 hours then passed into the small intestine.

Bile, from the liver, was added. It does the same thing as washing up liquid: breaks up the fats so we can digest them.

Enzymes, from the pancreas, was also added.

We used a sponge to carry

liquid with the nutrients to our

blood vessels.

The small intestine is 5,5 m long and is covered with tiny little finger-like things called villi.They act like sponges and absorb

nutrients straight into the blood system.

The large intestine

The large intestine sieved out moisture and nutrients, and the food dried up.

Our food then moved to the rectum, where it got its smell and colour. There we find not only the waste food that is sent there, but also dead skin and

organ cells and dead blood cells.

We added colacao (dead blood cells) to our food and put it into a little plastic bag(our rectum).

The longer our food stays in our rectum, the drier it is.We feel when it is time to go to the bathroom.

And……… we released the poo

through a hole in the plastic bag….

The End