2.3.11

Alveoli

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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.

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Large surface area

  • Alveoli have a large surface area.
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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.

Jump to other topics

1Cell Biology

1.1What's in Cells?

1.2Cell Division

1.3Transport in Cells

2Organisation

2.1Principles of Organisation

2.2Enzymes

2.3Circulatory System

2.4Non-Communicable Diseases

2.5Plant Tissues, Organs & Systems

3Infection & Response

4Bioenergetics

5Homeostasis & Response

5.1Homeostasis

5.2The Human Nervous System

5.3Hormonal Coordination in Humans

5.4Plant Hormones

6Inheritance, Variation & Evolution

7Ecology

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