Smell is also a process in which we cake
a molecule, which we call an odorant.
And we are going to sense
what that odorant is.
For these process, we need to have first
the molecule needs to enter the nasal cavity.
If then needs to coming close proximity
with these odorant receptors.
And these process has to be put
into a watery mucus solution.
So that odorant molecule needs to merge
before you can use your olfactory sensors
to determine what it smells like.
That information is then send back
to the brain through the ethmoid bone
and eventually to the olfactory tract.
The other cells that are important
to think about on this kind of diagram
are the mucus and serous secreting glands.
You need to produce a little bit of mucus
in your epithelium of your nasal tract
to be able to sense, smell an odorant.
How is this signal transduction work?
Olfactory receptors are
which they are many of them.
There are more than a hundred
that have been discovered does far.
These are specialized
G couple protein receptors.
And these protein responses have a special
Gof sensory molecule that is released.
These sensory molecule once the odor that binds
to it is a cyclic AMP stimulating molecule.
So these increases cyclic AMP within the cell.
Cyclic AMP does a couple of things for us,
it allows for calcium to rush in,
because we have cyclic AMP gated calcium channels
Cyclic AMP does several of things for us.
It allows for calcium to rush in because
we have cyclic AMP gated calcium channels.
These cyclic AMP gated calcium channels
then allow for other molecules such as
chloride to exit the cell.
Further increasing the polarization therefore
depolarization is a process with several stages.
Integration of Smell. As you know smells are complex.
There are a lot of different components to a smell.
You might have some intensity that usually
means, there’s more odorant molecules
or maybe certain types of odors are very
potent to one particular person or another.
All these signals are sent back
through the olfactory nerve.
But even though you have a hundred
or more, a different sensors.
They may be in acting multiples
with simply a normal smell.
So if you smell citrus, you are activating
many of these odorant sensing cells.
Other particular smells that may
have kind of a pungent in nature
are activating that different sort
of set of those odorant receptors
as you stimulate varying
amounts of these receptors.
You will get a global picture
of how something smells.
So it’s not simply having one odorant
molecule stimulating one receptor.
It’s a complex mixture of these odorants
hiding different olfactory receptors.