Alveoli: Adaptations for Gas Exchange (Edexcel IGCSE Biology)

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Alveoli

  • The alveoli are highly adapted and specialised for gas exchange

    • There are many rounded alveolar sacs which give a very large surface area to volume ratio

    • Alveoli (and the capillaries around them) have thin, single layers of cells to minimise diffusion distance

    • Ventilation maintains high levels of oxygen and low levels of carbon dioxide in the alveolar air space, meaning there is a steep concentration gradient for diffusion of gases

    • A good blood supply ensures a constant supply of blood high in carbon dioxide and low in oxygen, again to maintain concentration gradients for diffusion

    • A layer of moisture on the surface of the alveoli helps diffusion as gases dissolve

Adaptations of the alveolus 1, downloadable IGCSE & GCSE Biology revision notes
Adaptations of the alveolus 2_1, downloadable IGCSE & GCSE Biology revision notes

Alveoli are specifically adapted to maximise gas exchange

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Lára Marie McIvor

Author: Lára Marie McIvor

Expertise: Biology Lead

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.