An adult elephant's trunk consists of up to 300 pounds of hair, skin, connective tissue, fat, blood, vessels, and networks of muscles and nerves. While the trunk tip is especially rich in nerve networks, giving it a great sense of touch, the trunk's only job in smelling is to get the smells up into the head.
Nostrils run like two parallel hoses from the tip up to the head.
Within the nasal cavity are seven turbinals, or scrolls of bone, with sensitive tissues specialized for smelling. These extra turbinals give elephants more room for smelling to take place. Elephants can detect normal odors, but also other elephants' hormones, at great distances. Chemical information from each smell is passed on to an organ in the roof of the elephant's mouth for analysis. When the wind is right, an elephant can detect a smell about two miles away.