Sensory Physiology

2.5. Odor

Smell is perceived through the nose (nasal) and the throat (retronasal). Odor is perceived by olfactory cells, which line the olfactory mucosa. Each cell has a specific receptor, to which the odor carrying molecules can dock. The perceived sensation is translated into information for the brain. The sense of smell is closely related to the limbic system, which controls our emotions. Smells therefore always trigger a reaction as pleasant, unpleasant, safe, unsafe, as expected, unexpected, off-etc. Odors are usually made up from a mixture of more than 100 fragrances. Therefore, smells are difficult to describe. The brain usually compares perceived an aroma to saved “templates” and they are usually described as comparisons: “It smells like…”.

Humans can get used (adapt) to a particular smell and are then no longer able to perceive it.