Transcript Smell

Chemical Senses: Olfaction
Background
Olfactory
Pathway
2.
In
the olfactory
bulb,
primary
synapses
5.
Receptor
is G-protein-coupled
3. Axons
of
the
mitral
cells
form
a bundle
Organs
of
smell
3.Ends
of
the
olfactory
receptors
are
a
mucus
a.
Receptor
binding
activates
an
effector
Olfactory
receptors
between
the
olfactory
receptor
axons and
known
as
the
lateral
olfactory
tract
Olfaction--sense
of
smell
1. Not
the nose
(water
soluble)
Circuit
enzyme
(either
adenylate
cyclase
or
phospho1.Only
receptor
discussed
thus
far
that
are
mitral
cells
(the
projection
neuron
of
the
a.
Projects
primarily
to
the
pyriform
cortex
1.As
many
as
100,000
unique
odors
4.
500-1000
different
odor
binding
proteins
2. mucus
Olfactory
epithelium
a.This
contains
cells
of
the
immune
1.
Olfactory
receptor
cell
axons
leave
the
Projects
directly
to
the
cortex
lipase
C,
depending
on
the
nature
of
odorant)
neurons
(fire
action
potentials)
olfactory
system)
b.
Minority
to high
the
accessory
can
beprojections
discriminated
a.Each
olfactory
receptor
cell
expresses
only
a.
Thin
sheet
of
cells
upform
in our
system
and
is
shed
every
ten
minutes
olfactory
epithelium,
coalesce
to
a
large
1.
Cortex
then
projects
to
the
thalamus
and
b.
2nd
messenger
(cAMP
or IP3)
opens the
a Ca++
Only
neurons
in
the
nervous
system
that
a.
Glomeruli
olfactory
nuclei,
the
olfactory
tubercle,
a.
80%
of
which
are
noxious
one
type
ofcavity
binding
protein
nasal
i.
Individual
with
an
infection
(cold,
flu,
etc.)
number
of
bundles
(together
this
is
the
other
cortical
structure
channel
are
replaced
regularly
throughout
life
(every
i.
Spherical
arrangement
of
mitral
cells
enterorhinal
cortex,
and the
amygdala
b.Size
Odors
perceived
to be
noxiousis
are
5.
Receptor
is
G-protein-coupled
b.
of
the
olfactory
epithelium
one
sympton
is
a
runny
noise
olfactory
nerve,
cranial
nerve
I)
a.
Unique
c.
Ca++
influx
does
not
cause
NT
release
4-8
weeks)
b.
Within
the
bulb,in
there
are a number
of in
other
4. Pyramidal
cells
the
pyriform
cortex
often
deleterious
(rotting
meat,
etc.).
Proportionate
to
olfactory
acuity
(man
ii.
Mucus
is
shed
more
frequently
to
protect
a.
Run
directly
into
the
olfactory
bulb
i.
It
opens
a
Clchannel
2.
Olfactory
receptors
are
neurons
and
cells
that
contribute
to
formation
of
special
turn has
project
to the
thalamus,
neocortical
10
cm2,
dog
has170
cm2
, dogs also
the
olfactory
receptors
from
infection
d.
Cl- leaves
cell the
& membrane
isthe
depolarized
continuous
with
CNS
circuits
for
processing
olfactory
information
regions,
the
hippocampus
and
amygdala
have 100x a many receptors per
cm2
e.
Sufficient
causes
AP results
(e.g.,
granuledepolarization
and periglomerular
cells)
Exit
BASIM ZWAIN LECTURE NOTES
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