As you know, our circulation system includes the heart, lungs and blood vessels, such as arteries and veins.

The blood is simply our delivery system - it contains dissolved substances, either being delivered to the body's organs or being removed from them as waste. In addition, it has a role in protecting us from infection.

The heart is the organ that keeps the blood moving. It's made of muscle that squeezes and pushes the blood around the body, pumping around 100,000 times every day! The valves inside the heart ensure that blood is pumped in only the correct direction.

Our heart rate changes during exercise to pump more blood to the lungs and muscles, as there is a greater demand for oxygen and food, as well as a need to remove the extra wastes generated.

Let's use this activity to help us to consolidate our understanding of our circulatory system and also to extend what we already know in preparation for the biology course ahead.

Are you ready to begin?