Breathing and gas exchange
Every breath moves oxygen into your blood and carbon dioxide out — a swap that happens across a vast, thin surface deep in your chest.
Part of your national curriculum
- Biology: structure and function: Understand the structure and functions of the gas exchange system and the effects of exercise, asthma and smoking
Lesson overview
What you'll learn in this lesson
Understand the structure and functions of the gas exchange system and the effects of exercise, asthma and smoking
Key learning points
- • The pathway of air
- • Exercise and breathing rate
- • Asthma and smoking
This lesson at a glance
- 26 minutes
- 14 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 14
Watch first
Breathing and gas exchange
An English teaching video on this topic from Explore Planet English. Watch it, then scroll down for the lesson.
In a nutshell
Understand the structure and functions of the gas exchange system and the effects of exercise, asthma and smoking
Learning cycle
Part 2 of 14
Learning cycle 1 of 2
Part 1 · The pathway of air
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 14
Learn
The pathway of air
Air travels through the trachea, into two bronchi (one per lung), then smaller bronchioles, ending at millions of tiny air sacs called alveoli. Alveoli have thin walls, a huge surface area and a good blood supply, ideal for gas exchange by diffusion.
Explore the idea
Part 4 of 14
Learn
Exercise and breathing rate
During exercise, muscles respire faster, producing more carbon dioxide and using more oxygen. This increases breathing rate and heart rate, delivering oxygen faster and removing carbon dioxide before it builds up in the blood.
Quick check
Part 5 of 14
Quick check
Where does gas exchange happen in the lungs?
Reset break
Part 6 of 14
Pause
That's sitting 1 of 2 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 7 of 14
Quick check
Why does breathing rate increase during exercise?
Learning cycle
Part 8 of 14
Learning cycle 2 of 2
Part 2 · Asthma and smoking
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 9 of 14
Learn
Asthma and smoking
Asthma causes the airways to narrow and become inflamed, making breathing difficult, especially when triggered by allergens or exercise. Smoking damages the cilia that clear mucus, tars the alveoli walls (reducing surface area) and increases the risk of lung cancer and bronchitis.
Quick check
Part 10 of 14
Quick check
How does smoking damage the lungs?
Challenge round
Part 11 of 14
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 12 of 14
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
Alveoli have thin walls, a huge surface area and a good blood supply, ideal for gas ____ by diffusion.
Mastery quiz
Part 13 of 14
Marked quiz
End of lesson quiz: Breathing and gas exchange
4 questions, marked with the reasoning shown. No timer.
1. Why do alveoli have very thin walls and a huge combined surface area?
2. Where does gas exchange happen in the lungs?
3. Why does breathing rate increase during exercise?
4. How does smoking damage the lungs?
Lesson round-up
Part 14 of 14
Lesson round-up
Ready when you are
Quiz score
Not sat
Games
Not played
Points this lesson
0
Best run
0 in a row
Luna: 0 out of 3 on the practice checks. Only if you feel up to it — one more?
Ask LunaDo the work
Your written work for this lesson
This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.
Why the school greenhouse failed
A science club grew tomato plants in the school greenhouse. In June the plants grew well: leaves were dark green and the fruit set quickly. In July the club went away for two weeks and left the greenhouse door shut. When they came back, the leaves were curled and pale and most of the fruit had dropped.
The club had a data logger inside. It showed the temperature reached 46 °C on several afternoons and the soil moisture fell close to zero. The club knew photosynthesis needs light, water and carbon dioxide, and that enzymes in a plant work best in a narrow range of temperature. Above that range the enzymes stop working properly.
The club repeated the summer with the door propped open and a water bottle drip on each pot. Temperature peaked at 31 °C and the plants survived.
Written for Good Learning Co.
Reading questions
- Name the variable the club changed the second time, and one variable they kept the same.
- Explain, using the words photosynthesis and enzymes, why the plants were damaged in July.
- Write a conclusion for the club's report, saying how far the evidence supports it.
Method and results
WritingWrite the aim, what you changed, what you measured and what you kept the same, then record your results in a table.
1 page + results table
Conclusion
WritingExplain what your results show and why, using the scientific words from the lesson. Say how you know you can trust them.
6–8 sentences
Labelled diagram
DiagramDraw the apparatus or the process in pencil, label it fully, and photograph it.
1 labelled diagram
Reading and notes
ReadingRead the lesson text again and write the key ideas in your own words.
Half a page of notes
Saved as you type.
Part 1 of 14 · Watch & discover
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Understand the structure and functions of the gas exchange system and the effects of exercise, asthma and smoking