<s>
The	O
Pacinian	B-Algorithm
corpuscle	I-Algorithm
,	O
lamellar	B-Algorithm
corpuscle	I-Algorithm
or	O
Vater-Pacini	B-Algorithm
corpuscle	I-Algorithm
is	O
one	O
of	O
the	O
four	O
major	O
types	O
of	O
mechanoreceptors	O
(	O
specialized	O
nerve	O
ending	O
with	O
adventitious	O
tissue	O
for	O
mechanical	O
sensation	O
)	O
found	O
in	O
mammalian	O
skin	O
.	O
</s>
<s>
Most	O
of	O
the	O
Pacinian	B-Algorithm
corpuscles	I-Algorithm
act	O
as	O
rapidly	O
adapting	O
mechanoreceptors	O
.	O
</s>
<s>
Pacinian	B-Algorithm
corpuscles	I-Algorithm
are	O
larger	O
and	O
fewer	O
in	O
number	O
than	O
Meissner	B-Algorithm
's	I-Algorithm
corpuscle	I-Algorithm
,	O
Merkel	O
cells	O
and	O
Ruffini	B-Algorithm
's	I-Algorithm
corpuscles	I-Algorithm
.	O
</s>
<s>
The	O
Pacinian	B-Algorithm
corpuscle	I-Algorithm
is	O
approximately	O
oval-cylindrical-shaped	O
and	O
1mm	O
in	O
length	O
.	O
</s>
<s>
Its	O
capsule	O
consists	O
of	O
20	O
to	O
60	O
concentric	O
lamellae	O
(	O
hence	O
the	O
alternative	O
lamellar	B-Algorithm
corpuscle	I-Algorithm
)	O
including	O
fibroblasts	O
and	O
fibrous	O
connective	O
tissue	O
(	O
mainly	O
Type	O
IV	O
and	O
Type	O
II	O
collagen	O
network	O
)	O
,	O
separated	O
by	O
gelatinous	O
material	O
,	O
more	O
than	O
92%	O
of	O
which	O
is	O
water	O
.	O
</s>
<s>
Pacinian	B-Algorithm
corpuscles	I-Algorithm
are	O
rapidly	O
adapting	O
(	O
phasic	B-Architecture
)	O
receptors	O
that	O
detect	O
gross	O
pressure	O
changes	O
and	O
vibrations	O
in	O
the	O
skin	O
.	O
</s>
<s>
Any	O
deformation	O
in	O
the	O
corpuscle	O
causes	O
action	B-Algorithm
potentials	I-Algorithm
to	O
be	O
generated	O
by	O
opening	O
pressure-sensitive	O
sodium	O
ion	O
channels	O
in	O
the	O
axon	B-Algorithm
membrane	O
.	O
</s>
<s>
This	O
allows	O
sodium	O
ions	O
to	O
flow	O
into	O
the	O
cell	O
,	O
creating	O
a	O
receptor	B-Algorithm
potential	I-Algorithm
.	O
</s>
<s>
Pacinian	B-Algorithm
corpuscles	I-Algorithm
respond	O
when	O
the	O
skin	O
is	O
rapidly	O
indented	O
but	O
not	O
when	O
the	O
pressure	O
is	O
steady	O
,	O
due	O
to	O
the	O
layers	O
of	O
connective	O
tissue	O
that	O
cover	O
the	O
nerve	O
ending	O
.	O
</s>
<s>
Pacinian	B-Algorithm
corpuscles	I-Algorithm
have	O
a	O
large	O
receptive	O
field	O
on	O
the	O
skin	O
's	O
surface	O
with	O
an	O
especially	O
sensitive	O
center	O
.	O
</s>
<s>
Pacinian	B-Algorithm
corpuscles	I-Algorithm
sense	O
stimuli	O
due	O
to	O
the	O
deformation	O
of	O
their	O
lamellae	O
,	O
which	O
press	O
on	O
the	O
membrane	O
of	O
the	O
sensory	B-Architecture
neuron	I-Architecture
and	O
causes	O
it	O
to	O
bend	O
or	O
stretch	O
.	O
</s>
<s>
If	O
this	O
potential	O
reaches	O
a	O
certain	O
threshold	O
,	O
nerve	B-Algorithm
impulses	I-Algorithm
or	O
action	B-Algorithm
potentials	I-Algorithm
are	O
formed	O
by	O
pressure-sensitive	O
sodium	O
channels	O
at	O
the	O
first	O
node	O
of	O
Ranvier	O
,	O
the	O
first	O
node	O
of	O
the	O
myelinated	O
section	O
of	O
the	O
neurite	O
inside	O
the	O
capsule	O
.	O
</s>
<s>
This	O
impulse	O
is	O
now	O
transferred	O
along	O
the	O
axon	B-Algorithm
with	O
the	O
use	O
of	O
sodium	O
channels	O
and	O
sodium/potassium	O
pumps	O
in	O
the	O
axon	B-Algorithm
membrane	O
.	O
</s>
<s>
Action	B-Algorithm
potentials	I-Algorithm
are	O
formed	O
when	O
the	O
skin	O
is	O
rapidly	O
distorted	O
but	O
not	O
when	O
pressure	O
is	O
continuous	O
because	O
of	O
the	O
mechanical	O
filtering	O
of	O
the	O
stimulus	O
in	O
the	O
lamellar	O
structure	O
.	O
</s>
<s>
Pacinian	B-Algorithm
corpuscles	I-Algorithm
were	O
the	O
first	O
cellular	O
sensory	B-Architecture
receptor	I-Architecture
ever	O
observed	O
.	O
</s>
<s>
Similar	O
to	O
Pacinian	B-Algorithm
corpuscles	I-Algorithm
,	O
Herbst	O
corpuscles	O
and	O
Grandry	O
corpuscles	O
are	O
found	O
in	O
avian	O
species	O
.	O
</s>
