Your arteries are thick tubes that carry blood away from your heart.  This blood is bright red because it carries oxygen for the cells in the rest of your body.  As blood moves away from your heart, your arteries get smaller and smaller until they are very tiny.  They are now called capillaries.  Your capillaries are so thin that oxygen from your blood can transfer to the nearest cells and waste from your cells, like carbon dioxide, can be removed. 

To find our more, click on Find Out More.