Contents
Key Stage 3
Meaning
Alveoli are small air sacs in the lungs which are specially adapted for gas exchange.
A picture showing several alveoli and the capillaries supplying them with blood. |
Adaptations of Alveoli
- The alveoli have thin walls to allow gas exchange to happen quickly.
- Alveoli are in groups to make a large surface area in the lung for gas exchange.
- The alveoli have a good blood supply to allow gas exchange with the blood.
- The walls of the alveoli are kept moist to allow gases to dissolve into to the fluid for gas exchange with the blood.
About Alveoli
- The alveoli are where Oxygen enters the blood and Carbon Dioxide leaves the blood.
- There are thousands of alveoli in each lung.
- Alveoli are found at the end of bronchioles.
A diagram showing a single alveolus with the Oxygen going into the blood and Carbon Dioxide leaving the blood. |
Key Stage 4
Meaning
Alveoli are small air sacs in the lungs which are specially adapted for gas exchange.
Adaptations of Alveoli
- The walls of the alveoli separating the air from the blood are very thin allowing gases to diffuse quickly.
- The blood supply to the alveoli is very good to constantly supply of blood with little Oxygen and a lot of Carbon Dioxide keeping a high concentration gradient.
- The walls of the alveoli are kept moist to allow gases to dissolve into to the fluid for gas exchange with the blood.