Structure of the digestive system

The digestive system is made up of key parts, each of which has a different function.

Digestive enzymes and absorption

Enzymes are biological catalysts which speed up reactions including digestion.

Food energy

Food is a store of energy, transferred from the food to the consumer.

Healthy diet

A balanced diet contains the correct amount of all food groups.


There are two types of malnutrition: when and how do they occur?


'Obese' is a medical term used to describe a person with a high excess of body fat.

Lipids, oils and fats

Lipids include fats (solid at room temperature) and oils (liquid at room temperature).

Vitamins and minerals

Vitamins and minerals help the body to use other nutrients efficiently.


Proteins are a vital part of a healthy diet. Protein-rich foods include fish, meat, eggs and beans.

Dietary fibre

Dietary fibre is plant material that cannot be digested by the human body.


Carbohydrates are an important source of energy in a healthy diet. Starchy and sugary foods are high in carbohydrates.


Starch is a type of carbohydrate. Its molecules contain carbon, hydrogen and oxygen atoms.

What is poo?

Poo (faeces) is the waste that remains after food has been digested and its nutrients absorbed by the body.

Modelling the digestive system

Try this experiment and recreate processes in the digestive system with online and lab options.

7 Classroom videos

We have a selection of great videos for use in the classroom