Respiration
Every single cell in your body needs a constant supply of fresh air to stay alive. Join Bill Nye the Science Guy as we travel deep inside the human chest to discover exactly how our lungs pull life giving oxygen out of the invisible air around us.
Take a Deep Breath!
The diaphragm! This large parachute shaped muscle sits right under your lungs and pulls down to suck air into your body.
To combine with food and create energy! Your cells use oxygen to burn the fuel from your food so you can run, jump, and think.
Put Your Instincts to the Test
Think about what you already know about your own body. Pick an answer for each question, then see if your instincts were right.
Carbon dioxide! After your cells use the oxygen to make energy, they create carbon dioxide as a waste product that your lungs must quickly push out.
The size of a tennis court! Your lungs are packed with millions of tiny folds to maximize the space available to absorb oxygen into your blood.
Air from your lungs makes them vibrate! As you push air out of your windpipe, it rushes past your vocal cords causing them to buzz and create sound.
Understanding the Science
Tap each card to uncover the biological blueprints of the human respiratory system.
Key Concepts
Lungs
Tap to learn moreThe two spongy organs in your chest that expand to fill with air and shrink to push out waste gas.
Diaphragm
Tap to learn moreThe powerful sheet of muscle located directly below your lungs that does the heavy lifting of breathing.
Oxygen
Tap to learn moreThe vital invisible gas in the air that every single living cell in your body needs to survive.
Carbon Dioxide
Tap to learn moreThe invisible waste gas that your body produces when making energy, which you must breathe out to get rid of.
Cellular Respiration
Tap to learn moreThe incredible chemical process where your cells combine oxygen and food to create the energy you need to live.
Trachea
Tap to learn moreThe main windpipe tube that carries fresh air from your mouth and nose down into your chest.
Alveoli
Tap to learn moreThe millions of tiny air sacs inside your lungs where oxygen crosses over into your blood.
Cilia
Tap to learn moreTiny hairs inside your breathing tubes that sweep away dirt and dust to keep your lungs perfectly clean.
Try It: The Breathing Machine
Your lungs are not actually muscles! They rely entirely on the powerful diaphragm to do all the heavy lifting.
The Mission: Use the slider to contract the diaphragm downward, expanding the chest cavity to inhale fresh oxygen. Then, relax the muscle to let it arch back up, exhaling the carbon dioxide. Watch the dramatic change in lung size!
Apply Your Knowledge
Let us see if you can correctly identify the anatomy of your breathing system.
Match the Concepts
Click an anatomy term to select it, then click the matching description to place it.
Real-World Challenge
Fish do not have lungs like we do, but they still absolutely need oxygen to survive. Based on what you know about how we pull oxygen from the air, how do you think fish manage to get their oxygen while completely underwater?
What Has Changed Since This Episode Aired
This episode aired in 1994. While the core biology of breathing remains perfectly accurate, our medical technology to study and protect the lungs has advanced incredibly.
Updated: Yes! Today, medical imaging technology has allowed scientists to map the lungs in brilliant three dimensional detail. We now know that the millions of tiny alveoli sacs are even more complex and efficient at transferring oxygen than scientists previously thought!
Updated: Modern medicine has made huge leaps in respiratory health. Doctors can now use tiny robotic cameras to look deep inside the lungs of patients to spot problems early, and engineers have developed incredible artificial lungs to help sick people breathe while they heal!
Test Your Understanding
Answer these questions and get instant feedback. How many can you get right?
Results
Your score:
Reflection
Think about the last time you had a bad cold or a stuffed up nose. How did it change the way you normally breathe, and why do you think your body produces all that extra mucus when you are sick?
Episode Discussion
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