Structure and function of the gas exchange system

The human body takes in oxygen and lets out carbon dioxide. Many parts of the body are involved, including the lungs, airways and blood.


Respiration is a chemical reaction which occurs in all living cells, releasing energy from glucose.

The process of breathing

Breathing is also called 'ventilation' and is the movement of gases into and out from the lungs.

Anaerobic respiration

Anaerobic respiration occurs without oxygen and releases less energy but more quickly than aerobic respiration.

Lactic acid

Lactic acid is the waste product produced during anaerobic respiration.

The circulatory system

The circulatory system is the heart and all the blood vessels in the body which carry cells and substances to all its parts.

The effect of asthma, smoking and exercise on the gas exchange system

The gas exchange system is the parts of the body involved in breathing, such as the lungs, airways and diaphragm. Different conditions and activities affect this system.


Cells get the energy they need from glucose during respiration. Watch a visual explanation of glucose.


Photosynthesis is a chemical reaction that takes place inside a plant, producing food for the plant to survive.

Photosynthesis and respiration in plants

Photosynthesis and respiration are processes that allow plants to make food and release energy.

Factors affecting the rate of photosynthesis in crop growing

Temperature, light intensity and carbon dioxide are just some of the factors that affect photosynthesis. These factors can be manipulated to maximise growth.

Investigating the rate of photosynthesis

Try this experiment and use pondweed to see how light intensity affects the rate of photosynthesis.

How to measure your lung capacity

The maximum amount of air you can breathe in and out is your vital lung capacity. This experiment shows how this can be measured.

3 Classroom videos

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