The nose is an area on the front end of the head. It usually has two openings. Some animal noses stick out as man's does. The trunk of an elephant is its nose. Most animals, however, have flat noses which are part of the upper jaw area. The nose is used to smell things that are in air or water. Animals with lungs use the nose in breathing.
The external nose is made of skin, bone, and CARTILAGE. The internal nose consists of two airways separated by a septum. The minute hairs in the nose function as air filters. The cells lining the tubes secrete mucus which moistens the surface. The olfactory nerves are stimulated when certain odors reach the nose. These chemo-receptors send the message to the brain.