Anatomy PhysiologyMy Heart and Lungs Keep Me Going
Atlas leaps in place inside a bright sunny classroom, thumping his chest to the steady beat of a glowing red heart visible through a body outline, then spreads his arms wide as two soft pink lungs fill with golden sparkles on every breath in and release faint gray wisps on every breath out.
- Name the heart and the lungs as two body parts inside your chest.
- Explain that the heart pumps blood that carries oxygen all around the body.
- Explain that the lungs take in oxygen when you breathe in and release carbon dioxide when you breathe out.
- Describe how the heart and lungs work together to keep you alive and active.
- Describe what it feels like when your heart beats faster and you breathe harder during exercise.
Key terms
- heart
- A strong muscle in your chest that pumps blood around your body.
- lungs
- Two soft body parts in your chest that take in air.
- oxygen
- A gas in the air that your body needs to make energy.
- carbon dioxide
- A waste gas your body breathes out when you exhale.
- pulse
- The steady beat you can feel when your heart pumps blood.
The Heart Is a Pump
Your heart is a strong muscle about the size of your fist, sitting in your chest a little to the left. It squeezes over and over to pump blood through tubes called blood vessels to every part of your body. The blood carries oxygen and food to your cells, then returns to the heart to be pumped out again. Your heart never stops, even when you sleep.
The Lungs Trade Gases
When you breathe in, air travels into your two lungs, which pull oxygen out of the air. When you breathe out, your lungs release carbon dioxide, a waste gas your body does not need. This swap of taking in oxygen and getting rid of carbon dioxide is called gas exchange, and it happens with every single breath.
A Powerful Team
The heart and lungs are partners. The lungs load oxygen into the blood, and the heart pumps that oxygen-rich blood out to your muscles, brain, and toes. When you exercise, your muscles need more oxygen, so your heart beats faster and you breathe harder at the same time. Neither organ can keep you going without the other.
Worked examples
Explain why you breathe harder when you run.
- Running muscles need extra oxygen to make more energy.
- Your lungs breathe faster to take in more oxygen from the air.
- Your heart beats faster to pump that oxygen-rich blood to your muscles quickly.
Answer: Your muscles need more oxygen, so your lungs and heart both speed up to deliver it.
Decide which organ takes oxygen out of the air.
- The heart pumps blood but does not touch the air you breathe.
- The lungs are the parts that fill with air when you breathe in.
- So the lungs are what take oxygen out of the air.
Answer: The lungs take oxygen out of the air.
Activity
Match each body part card to the picture that shows its job.
Practice
Name the gas your lungs take in and the gas they push out.
Why do your heart and lungs both speed up when you exercise?
Common mistakes to avoid
- The heart rests when you sleep.The heart beats all the time, day and night, because your body always needs blood.
- The lungs send oxygen to your toes by themselves.The lungs collect oxygen, but the heart must pump the blood that carries it everywhere.
Check your understanding
What does your heart do?
What do your lungs do when you breathe in?
Why do you breathe harder and your heart beats faster when you run?
Recap
Your heart pumps blood that carries oxygen all around your body, and your lungs take in oxygen and release carbon dioxide. They work as a team to keep you alive, and both speed up when you exercise.
Reflect
How does it feel in your chest right after you run, and which organs are working hardest then?