Chemical Senses- Smell and Olfaction

The mucosa of most of the nasal cavity has no olfactory function. The olfactory receptors are found in the nasal mucosa in a reduced region - the olfactory area, represented by the walls of a narrow niche formed by the upper nasal cornet, the upper septum and the roof of the nasal cavity (the cryobriform lamina of the etmoid). The smell is very similar to taste, being described by some as taste at a distance . Olfactive recipients adapt quickly. It is common that an unpleasant smell, at first very difficult to bear, becomes quickly inacceptable. Generally, the olfactory potential of some chemical compounds belonging to a homologous series grow progressively from the lower compounds of the series to the upper ones. The division of odors by category is a very difficult problem. In case of olfaction there are no fundamental qualities that can be compared with taste sensations: sweet, sour, bitter salty . The large number of perceptible odors asks a question to which the answer has not yet been found, namely: What is the mechanism behind the olfactory differentiation? .What can we distinguish between two odors?