Oh, wow, oh, oh, whoa, oh, wow.

Oh, wow.

Oh, wow. Hello, you're all right.

Hello, you're listening to The Science of Everything podcast, episode 59, smell.

And I'm your host, James Fodor.

Recommended pre-listening for this episode is episode 38, neurons and synapses.

Also, if you've listened to the previous episode on Taste, that will help a little bit,

but that's not really very essential.

But you do need to have some basic understanding of synapses and synaptic processing and action potentials and things like that if you're really to understand this episode.

So in this episode, we're going to look at the sense of smell, more properly known as olfaction.

I'll talk about the structures in the nasal cavity responsible for the transduction or the reception

of olfactory sensation. I'll talk about the receptor proteins, the olfactory bulb, the olfactory epithelium,

those structures there. I'll talk about how the signals are transmitted to the brain and some of the pathways involved there.

I'll also say a little bit about smell in

animals and how that compares to humans. All right, so let's get started. Smell like taste

is a type of chemical receptor. That means that the sensory apparatus operates by binding

to specific chemicals. This is distinct from, say, the

vision which is, in which sensory transduction occurs by cells that are responsive to photons,

light, or other mechanoreceptors, which are receptive to motion. Smell is a type of chemoreception

in which the sensory molecules are receptive to particular chemicals.

The chemicals themselves are called odourants. If you remember from the previous episode,

the molecules that were detected by the taste buds were called tastens. So in this episode we have odourants. Although taste and smell are separate sensory systems in land animals, they are closely related to each other, as we'll see a bit later.

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