7.1
The gas exchange system
Follow air from your nose down to the alveoli, see how the alveoli are built for swapping gases, and how your airways keep themselves clean.
7.2
Breathing in and out
See how muscles change the size of your chest, why that makes air move, how a bell jar models it, and how to measure the air you breathe out.
7.3
Gas exchange in the alveoli
Watch oxygen diffuse into the blood and carbon dioxide diffuse out, compare the air you breathe in and out, and test it with limewater.
7.4
Exercise, asthma, smoking and stomata
See how exercise changes your breathing, what happens in an asthma attack, what smoking does to your lungs, and how leaves exchange gases.
Daily 5
Five quick diagram questions a day from this unit. The ones you get wrong come back sooner. Progress saves in this browser.
What this unit covers
Mapped to the KS3 national curriculum (Biology: gas exchange systems).
| Programme of study | Lesson |
|---|---|
| the structure and functions of the gas exchange system in humans, including adaptations to function | 7.1, 7.3 |
| the mechanism of breathing to move air in and out of the lungs, using a pressure model to explain the movement of gases, including simple measurements of lung volume | 7.2 |
| the impact of exercise, asthma and smoking on the human gas exchange system | 7.4 |
| the role of leaf stomata in gas exchange in plants | 7.4 |