<s>
A	O
thermoreceptor	B-Algorithm
is	O
a	O
non-specialised	O
sense	B-Architecture
receptor	I-Architecture
,	O
or	O
more	O
accurately	O
the	O
receptive	O
portion	O
of	O
a	O
sensory	B-Architecture
neuron	I-Architecture
,	O
that	O
codes	O
absolute	O
and	O
relative	O
changes	O
in	O
temperature	O
,	O
primarily	O
within	O
the	O
innocuous	O
range	O
.	O
</s>
<s>
In	O
the	O
mammalian	O
peripheral	O
nervous	O
system	O
,	O
warmth	B-Algorithm
receptors	I-Algorithm
are	O
thought	O
to	O
be	O
unmyelinated	O
C-fibres	O
(	O
low	O
conduction	O
velocity	O
)	O
,	O
while	O
those	O
responding	O
to	O
cold	O
have	O
both	O
C-fibers	O
and	O
thinly	O
myelinated	O
A	O
delta	O
fibers	O
(	O
faster	O
conduction	O
velocity	O
)	O
.	O
</s>
<s>
For	O
cold	B-Algorithm
receptors	I-Algorithm
their	O
firing	O
rate	O
increases	O
during	O
cooling	O
and	O
decreases	O
during	O
warming	O
.	O
</s>
<s>
Some	O
cold	B-Algorithm
receptors	I-Algorithm
also	O
respond	O
with	O
a	O
brief	O
action	O
potential	O
discharge	O
to	O
high	O
temperatures	O
,	O
i.e.	O
</s>
<s>
In	O
mammals	O
,	O
temperature	B-Algorithm
receptors	I-Algorithm
innervate	O
various	O
tissues	O
including	O
the	O
skin	O
(	O
as	O
cutaeneous	O
receptors	O
)	O
,	O
cornea	O
and	O
urinary	O
bladder	O
.	O
</s>
<s>
The	O
hypothalamus	O
is	O
involved	O
in	O
thermoregulation	O
,	O
the	O
thermoreceptors	B-Algorithm
allowing	O
feed-forward	O
responses	O
to	O
a	O
predicted	O
change	O
in	O
core	O
body	O
temperature	O
in	O
response	O
to	O
changing	O
environmental	O
conditions	O
.	O
</s>
<s>
Thermoreceptors	B-Algorithm
have	O
been	O
classically	O
described	O
as	O
having	O
'	O
free	O
 '	O
non-specialized	O
endings	O
;	O
the	O
mechanism	O
of	O
activation	O
in	O
response	O
to	O
temperature	O
changes	O
is	O
not	O
completely	O
understood	O
.	O
</s>
<s>
Cold-sensitive	O
thermoreceptors	B-Algorithm
give	O
rise	O
to	O
the	O
sensations	O
of	O
cooling	O
,	O
cold	O
and	O
freshness	O
.	O
</s>
<s>
In	O
the	O
cornea	O
cold	B-Algorithm
receptors	I-Algorithm
are	O
thought	O
to	O
respond	O
with	O
an	O
increase	O
in	O
firing	O
rate	O
to	O
cooling	O
produced	O
by	O
evaporation	O
of	O
lacrimal	O
fluid	O
'	O
tears	O
 '	O
and	O
thereby	O
to	O
elicit	O
a	O
blink	O
reflex	O
.	O
</s>
<s>
Other	O
thermoreceptors	B-Algorithm
will	O
react	O
to	O
opposite	O
triggers	O
and	O
give	O
rise	O
to	O
heat	O
and	O
in	O
some	O
cases	O
even	O
burning	O
sensations	O
.	O
</s>
<s>
In	O
order	O
for	O
fibers	O
to	O
do	O
so	O
,	O
they	O
must	O
have	O
a	O
specific	O
thermoreceptor	B-Algorithm
.	O
</s>
<s>
The	O
thermoreceptor	B-Algorithm
reacting	O
to	O
capsaicin	O
and	O
other	O
heat	O
producing	O
chemicals	O
is	O
known	O
as	O
TRPV1	O
.	O
</s>
<s>
Warm	O
and	O
cold	B-Algorithm
receptors	I-Algorithm
play	O
a	O
part	O
in	O
sensing	O
innocuous	O
environmental	O
temperature	O
.	O
</s>
<s>
Temperatures	O
likely	O
to	O
damage	O
an	O
organism	O
are	O
sensed	O
by	O
sub-categories	O
of	O
nociceptors	B-Algorithm
that	O
may	O
respond	O
to	O
noxious	O
cold	O
,	O
noxious	O
heat	O
or	O
more	O
than	O
one	O
noxious	O
stimulus	O
modality	O
(	O
i.e.	O
,	O
they	O
are	O
polymodal	O
)	O
.	O
</s>
<s>
The	O
nerve	O
endings	O
of	O
sensory	B-Architecture
neurons	I-Architecture
that	O
respond	O
preferentially	O
to	O
cooling	O
are	O
found	O
in	O
moderate	O
density	O
in	O
the	O
skin	O
but	O
also	O
occur	O
in	O
relatively	O
high	O
spatial	O
density	O
in	O
the	O
cornea	O
,	O
tongue	O
,	O
bladder	O
,	O
and	O
facial	O
skin	O
.	O
</s>
<s>
The	O
speculation	O
is	O
that	O
lingual	O
cold	B-Algorithm
receptors	I-Algorithm
deliver	O
information	O
that	O
modulates	O
the	O
sense	O
of	O
taste	O
;	O
i.e.	O
</s>
<s>
The	O
transduction	O
of	O
temperature	O
in	O
cold	B-Algorithm
receptors	I-Algorithm
is	O
mediated	O
in	O
part	O
by	O
the	O
TRPM8	O
channel	O
.	O
</s>
<s>
The	O
feeling	O
of	O
freshness	O
associated	O
with	O
the	O
activation	O
of	O
cold	B-Algorithm
receptors	I-Algorithm
by	O
menthol	O
,	O
particularly	O
those	O
in	O
facial	O
areas	O
with	O
axons	O
in	O
the	O
trigeminal	O
(	O
V	O
)	O
nerve	O
,	O
accounts	O
for	O
its	O
use	O
in	O
numerous	O
toiletries	O
including	O
toothpaste	O
,	O
shaving	O
lotions	O
,	O
facial	O
creams	O
and	O
the	O
like	O
.	O
</s>
<s>
It	O
has	O
been	O
suggested	O
that	O
it	O
is	O
the	O
constellation	O
of	O
various	O
thermally	O
sensitive	O
proteins	O
together	O
in	O
a	O
neuron	O
that	O
gives	O
rise	O
to	O
a	O
cold	B-Algorithm
receptor	I-Algorithm
.	O
</s>
