The body's delivery system
The blood circulatory system carries blood all around your body. It is made of the heart, the blood vessels (tubes) and the blood itself. Blood never stops moving while you are alive.
Key idea
The heart is a strong muscle that pumps blood. Blood carries oxygen and food to every part of the body, and takes away waste like carbon dioxide.
The heartbeat
Your heart beats all day and night, even when you sleep. When you run or play, your heart beats faster to send more oxygen to your muscles. You can feel this fast beating with your hand on your chest.
- The heart pumps the blood.
- Blood vessels are the tubes that carry blood.
- Blood carries oxygen, food and waste.
Blood flows out from the heart, travels to every part of the body, and then comes back to the heart again. This never-ending loop is why we call it circulation. Blood also helps your body fight germs and heal small cuts, so keeping your heart healthy is very important.
Example
After running in the field, your heart beats fast and you breathe hard because your body needs more oxygen.