The Nose

Modified: 2020-03-18

The nose is a transducer of volatile chemicals, or chemicals that are in the gaseous state. Most, but not all, of the chemicals we smell are organic (composed of carbon molecules). For us to be able to smell, the chemical must also be dissolvable in the nasal mucosa. That is why you cannot smell as well as when you have a cold. You have too much nasal mucus.

As a species, we depend on the sense of smell to a much lower degree than many other animals do. One reason for this is the size of our olfactory apparatus. It is relatively smaller than that of dogs and rats, for example. It appears that those two species are much more dependent on their sense of smell than we are. We will look as some exceptions to that rule in humans in the next chapter.

Note that the olfactory system is the only sense system that does not synapse through the thalamus. Rather it is connected directly to the cortex.

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