It delivers oxygen and glucose to the tissues for respiration, which is the release of energy to cells. This video is about how arteries carry blood away from the heart. Find out more about GCSE ...

All organisms need ATP to live. Respiration is only around 40 per cent efficient. As animals respire, heat is also released. In birds and mammals, this heat is distributed around the body by the ...

This process requires specialized organs such as the lungs or gills. This oxygen is used for cellular respiration and metabolism, a byproduct of which is carbon dioxide.