So the gas exchange system is made up of your lungs and your airways. The lungs fill with oxygen-rich air from the atmosphere and this oxygen is then transferred into your blood via the alveoli.

Alveoli At the ends of bronchioles are tiny ... The Human Body viewers are taken on a journey around the Circulatory system. BBC Teach has thousands of free, curriculum-linked resources to help ...

Alveolar macrophages — white blood cells that are part of the immune system and found in the alveoli or ‘air sacs’ of the lungs — remove dust and microorganisms from the airways.

Air pollution is a well-known risk factor for respiratory diseases such as asthma and chronic obstructive pulmonary disease ...