The Nose diagrams are available at various hospitals and health clubs. These Nose diagrams explain the nose functional process clearly. The upper air passages refer to the respiratory organs in the head of the human being. They include the nose and throat pharynx. The sensory receptors of the olfactory organ are located at the start of the respiratory tracts and have the size of a dime on the upper nasal wall and the septum. A water-soluble property increases the ability to smell because the smell molecules enter the air through evaporation.