Biological Olfaction - The Electronic Nose Artificial Olfaction Technology - page 70

3.3.1 Olfactory Receptors

Receptor cell as shown in Fig. 3.5 , embedded in a specialized patch of yellow-tinted
mucous membrane in the roof of the nasal cavity is called olfactory receptors. It's
only neurons that regularly die as its life span is 5-8 weeks and are replaced by new
one. There are 10-20 million receptor cells spread in the middle of the supporting
cells of the mucous membrane. Dendrites defined as extensions of receptor cells
have to carry electrical signals into the cell body. It has cilia that is projecting from
the dendritic knob into the surface of the mucus layer which has micro tubular hair
like structures and on which the receptors for odorants are located. Cilia contain the
active sites for the olfactory transduction process. Figure 3.6 shows the basic neu-
ron. A neuron which is bipolar and covered with non-motile cilia called receptors.
Axons from the olfactory receptors enter small nerve bundles (collectively termed

Fig. 3.5 Receptor cell

Fig. 3.6 A neuron