Your heart is a muscle about the size of your fist. It pumps blood all round your body through tubes called blood vessels. Arteries carry blood away from the heart, veins carry it back, and tiny capillaries join them. Blood carries oxygen, food and water to every part of the body and takes waste away.
Your lungs take in oxygen when you breathe in and get rid of carbon dioxide when you breathe out. Blood picks up oxygen in the lungs and the heart pumps it round the body. When you exercise, your muscles need more oxygen, so your heart beats faster and you breathe faster. You can feel your pulse in your wrist: each beat is your heart pumping.
Worked example
Why does your pulse go up when you run?
- Running muscles need more oxygen and food.
- Blood carries oxygen to them.
Answer:The heart beats faster to pump more blood, so the pulse rises.
Key words
- heart
- the muscle that pumps blood
- artery
- carries blood away from the heart
- vein
- carries blood back to the heart
- pulse
- the beat you can feel as the heart pumps
New questions every time.
NGSS-referenced: 5-LS1-1