Alveoli
Biology: AQA GCSE Higher, topic 2.3.11
Alveoli
Alveoli are tiny air sacs that are found in the lungs. Oxygen and carbon dioxide move between the air and blood by diffusion in the alveoli. Alveoli are adapted so that the exchange of substances across their surface is very efficient.
Large surface area
- Alveoli have a large surface area.
Surrounded by capillaries
- Alveoli are surrounded by a network of capillaries. This means that:
- Alveoli have a rich blood supply.
- The distance that gases need to diffuse across is small.
Test yourself on Alveoli
Why does having a network of capillaries close to each alveolus make gas exchange more efficient?
Which of the following are true of the alveoli in the lungs?
Why do whales need to store oxygen in their muscles?
Why do alveoli have a large surface area?