small size - each of the alveoli is a small sphere about 300 μm in diameter, giving it a larger surface area to volume ratio than larger structures number - there are around 700 million alveoli ...

If the lungs become damaged the alveoli can break down and the lung surface area is reduced, so diffusion is impaired. If the lungs become inflamed the airway is constricted and it becomes ...

The cells in the body need oxygen to release energy from food efficiently by carrying out aerobic respiration. A waste product of aerobic respiration is carbon dioxide. The layer of moisture in ...