Digestive system

Matspjälkningsapparaten

Catherine Mortimer-Hawkins, Edsbergsskolan

What do we eat and why?

– The main nutrients the body needs are:

carbohydrates (kolhydrater) for energy;

proteins (proteiner) for growth and repair;

fats (fetter) to store energy;

vitamins and minerals to keep the body healthy.

What is carbohydrates, proteins and fats?Carbohydrate

moleculeone sugar molecule

protein molecule

one amino acid

fat molecule

glycerol

fatty acids

The digestive system is really

one long tube with an opening

at each end.

Stretched out it is a 9m tube!

anus

mouth

But how does a 9m tube fit into a space,

which is less than a metre long?

Okidoki!! Let’s go for a ride throughyour body!

Digestion begins in the mouth where food is broken down by the teeth. This is called mechanical breakdown. The small parts of food are mixed with saliva and swallowed.

After food is swallowed it enters the stomach, which is basically a muscular bag filled with hydrochloric acid.

muscletissuefood leaves

the stomach

food enters from the gullet

Two things happen to food in the stomach:

the chemical breakdown of food begins;microbes are destroyed.

The stomach

Digestive enzymes are the chemicals that break large food molecules into smaller molecules. Otherwise the molecules are to big for our body to take up!

Duodenum - tolvfingertarm

• Here the digested food is mixed with bile from the gallbladder and juices from the pancreas.

The bile:• Breaks up larger fat drops

to smaller droplets

The juices from the pancreas:• Neutralize the acid from the stomach• Mix the digested food with enzymes

Enzymes

long carbohydrate molecule

sugarmolecules

long protein molecule amino acid molecules

Pepsin

glyc

ero

l

+

fatty acidsLipas

Amylas

The small intestine

It is in the small instestine the small moleculesgets through the thin walls and reachesthe blood vessels.

The walls are folded in so called villi (tarmludd).

The large intestine

Here in the large intestine water is suckedback into the body.

If this doesn’t work… then you get diarrhea.

Coli bacteria lives in the large intestineand help making K-vitamins.They help with the last of the digestion and then also make methane gas….

…a fart in other words!

The anus

The ex-food leaves the bodythrough the anus.

When the poo reaches the anussignals are sent to the brain torelax the muscles and the poois pressed out.

Glossary

carbohydrate – A nutrient in food that provides energy.

enzyme – A chemical that helps digestion by breaking large molecules into smaller ones.

fat – A nutrient in food that provides a store of energy.

large intestine – The organ where water is removed from undigested food.

minerals – Compounds in food that provide the elements needed in small amounts for a healthy diet.

protein – A nutrient in food needed for growth and repair.

small intestine – The organ where digestion is completed and digested food molecules are absorbed.

stomach – The organ where food is mixed with acid and enzymes.

vitamins – Substances found in food that are needed in