<s>
Baroreceptors	B-Algorithm
(	O
or	O
archaically	O
,	O
pressoreceptors	B-Algorithm
)	O
are	O
sensors	O
located	O
in	O
the	O
carotid	O
sinus	O
(	O
at	O
the	O
bifurcation	O
of	O
common	O
carotid	O
artery	O
into	O
external	O
and	O
internal	O
carotids	O
)	O
and	O
in	O
the	O
aortic	O
arch	O
.	O
</s>
<s>
Baroreceptors	B-Algorithm
are	O
a	O
type	O
of	O
mechanoreceptor	O
sensory	O
neuron	O
that	O
are	O
excited	O
by	O
a	O
stretch	O
of	O
the	O
blood	O
vessel	O
.	O
</s>
<s>
Thus	O
,	O
increases	O
in	O
the	O
pressure	O
of	O
blood	O
vessel	O
triggers	O
increased	O
action	B-Algorithm
potential	I-Algorithm
generation	O
rates	O
and	O
provides	O
information	O
to	O
the	O
central	O
nervous	O
system	O
.	O
</s>
<s>
Baroreceptors	B-Algorithm
act	O
immediately	O
as	O
part	O
of	O
a	O
negative	O
feedback	O
system	O
called	O
the	O
baroreflex	O
,	O
as	O
soon	O
as	O
there	O
is	O
a	O
change	O
from	O
the	O
usual	O
mean	O
arterial	O
blood	O
pressure	O
,	O
returning	O
the	O
pressure	O
toward	O
a	O
normal	O
level	O
.	O
</s>
<s>
The	O
solitary	O
nucleus	O
in	O
the	O
medulla	O
oblongata	O
of	O
the	O
brain	O
recognizes	O
changes	O
in	O
the	O
firing	O
rate	O
of	O
action	B-Algorithm
potentials	I-Algorithm
from	O
the	O
baroreceptors	B-Algorithm
,	O
and	O
influences	O
cardiac	O
output	O
and	O
systemic	O
vascular	O
resistance	O
.	O
</s>
<s>
Baroreceptors	B-Algorithm
can	O
be	O
divided	O
into	O
two	O
categories	O
based	O
on	O
the	O
type	O
of	O
blood	O
vessel	O
in	O
which	O
they	O
are	O
located	O
:	O
high-pressure	O
arterial	O
baroreceptors	B-Algorithm
and	O
low-pressure	O
baroreceptors	B-Algorithm
(	O
also	O
known	O
as	O
cardiopulmonary	O
or	O
volume	O
receptors	O
)	O
.	O
</s>
<s>
Arterial	O
baroreceptors	B-Algorithm
are	O
stretch	O
receptors	O
that	O
are	O
stimulated	O
by	O
distortion	O
of	O
the	O
arterial	O
wall	O
when	O
pressure	O
changes	O
.	O
</s>
<s>
The	O
baroreceptors	B-Algorithm
can	O
identify	O
the	O
changes	O
in	O
both	O
the	O
average	O
blood	O
pressure	O
or	O
the	O
rate	O
of	O
change	O
in	O
pressure	O
with	O
each	O
arterial	O
pulse	O
.	O
</s>
<s>
Action	B-Algorithm
potentials	I-Algorithm
triggered	O
in	O
the	O
baroreceptor	B-Algorithm
ending	O
are	O
then	O
directly	O
conducted	O
to	O
the	O
brainstem	O
where	O
central	O
terminations	O
(	O
synapses	O
)	O
transmit	O
this	O
information	O
to	O
neurons	O
within	O
the	O
solitary	O
nucleus	O
which	O
lies	O
in	O
the	O
medulla	O
.	O
</s>
<s>
Reflex	O
responses	O
from	O
such	O
baroreceptor	B-Algorithm
activity	O
can	O
trigger	O
increases	O
or	O
decreases	O
in	O
the	O
heart	O
rate	O
.	O
</s>
<s>
Arterial	O
baroreceptor	B-Algorithm
sensory	O
endings	O
are	O
simple	O
,	O
splayed	O
nerve	O
endings	O
that	O
lie	O
in	O
the	O
tunica	O
adventitia	O
of	O
the	O
artery	O
.	O
</s>
<s>
An	O
increase	O
in	O
the	O
mean	O
arterial	O
pressure	O
increases	O
depolarization	O
of	O
these	O
sensory	O
endings	O
,	O
which	O
results	O
in	O
action	B-Algorithm
potentials	I-Algorithm
.	O
</s>
<s>
These	O
action	B-Algorithm
potentials	I-Algorithm
are	O
conducted	O
to	O
the	O
solitary	O
nucleus	O
in	O
the	O
central	O
nervous	O
system	O
by	O
axons	B-Algorithm
and	O
have	O
a	O
reflex	O
effect	O
on	O
the	O
cardiovascular	O
system	O
through	O
autonomic	O
neurons	O
.	O
</s>
<s>
Hormone	O
secretions	O
that	O
target	O
the	O
heart	O
and	O
blood	O
vessels	O
are	O
affected	O
by	O
the	O
stimulation	O
of	O
baroreceptors	B-Algorithm
.	O
</s>
<s>
At	O
normal	O
resting	O
blood	O
pressures	O
,	O
baroreceptors	B-Algorithm
discharge	O
with	O
each	O
heart	O
beat	O
.	O
</s>
<s>
If	O
blood	O
pressure	O
falls	O
,	O
such	O
as	O
on	O
orthostatic	O
hypotension	O
or	O
in	O
hypovolaemic	O
shock	O
,	O
baroreceptor	B-Algorithm
firing	O
rate	O
decreases	O
and	O
baroreceptor	B-Algorithm
reflexes	O
act	O
to	O
help	O
restore	O
blood	O
pressure	O
by	O
increasing	O
heart	O
rate	O
.	O
</s>
<s>
Signals	O
from	O
the	O
carotid	O
baroreceptors	B-Algorithm
are	O
sent	O
via	O
the	O
glossopharyngeal	O
nerve	O
(	O
cranial	O
nerve	O
IX	O
)	O
.	O
</s>
<s>
Signals	O
from	O
the	O
aortic	B-Algorithm
baroreceptors	I-Algorithm
travel	O
through	O
the	O
vagus	O
nerve	O
(	O
cranial	O
nerve	O
X	O
)	O
.	O
</s>
<s>
Carotid	O
sinus	O
baroreceptors	B-Algorithm
are	O
responsive	O
to	O
both	O
increases	O
or	O
decreases	O
in	O
arterial	O
pressure	O
,	O
while	O
aortic	O
arch	O
baroreceptors	B-Algorithm
are	O
only	O
responsive	O
to	O
increases	O
in	O
arterial	O
pressure	O
.	O
</s>
<s>
Arterial	O
baroreceptors	B-Algorithm
inform	O
reflexes	O
about	O
arterial	O
blood	O
pressure	O
but	O
other	O
stretch	O
receptors	O
in	O
the	O
large	O
veins	O
and	O
right	O
atrium	O
convey	O
information	O
about	O
the	O
low	O
pressure	O
parts	O
of	O
the	O
circulatory	O
system	O
.	O
</s>
<s>
Baroreceptors	B-Algorithm
respond	O
very	O
quickly	O
to	O
maintain	O
a	O
stable	O
blood	O
pressure	O
,	O
but	O
their	O
responses	O
diminish	O
with	O
time	O
and	O
thus	O
are	O
most	O
effective	O
for	O
conveying	O
short	O
term	O
changes	O
in	O
blood	O
pressure	O
.	O
</s>
<s>
In	O
people	O
with	O
essential	O
hypertension	O
the	O
baroreceptors	B-Algorithm
and	O
their	O
reflexes	O
change	O
and	O
function	O
to	O
maintain	O
the	O
elevated	O
blood	O
pressure	O
as	O
if	O
normal	O
.	O
</s>
<s>
Electrical	O
stimulation	O
of	O
baroreceptors	B-Algorithm
has	O
been	O
found	O
to	O
activate	O
the	O
baroreflex	O
,	O
reducing	O
sympathetic	O
tone	O
throughout	O
the	O
body	O
and	O
thereby	O
reducing	O
blood	O
pressure	O
in	O
patients	O
with	O
resistant	O
hypertension	O
.	O
</s>
<s>
The	O
low-pressure	O
baroreceptors	B-Algorithm
,	O
are	O
found	O
in	O
large	O
systemic	O
veins	O
,	O
in	O
pulmonary	O
vessels	O
,	O
and	O
in	O
the	O
walls	O
of	O
the	O
right	O
atrium	O
and	O
ventricles	O
of	O
the	O
heart	O
(	O
the	O
atrial	O
volume	O
receptors	O
)	O
.	O
</s>
<s>
The	O
low-pressure	O
baroreceptors	B-Algorithm
are	O
involved	O
with	O
the	O
regulation	O
of	O
blood	O
volume	O
.	O
</s>
<s>
The	O
low-pressure	O
baroreceptors	B-Algorithm
have	O
both	O
circulatory	O
and	O
renal	O
effects	O
;	O
they	O
produce	O
changes	O
in	O
hormone	O
secretion	O
,	O
resulting	O
in	O
profound	O
effects	O
on	O
the	O
retention	O
of	O
salt	O
and	O
water	O
;	O
they	O
also	O
influence	O
intake	O
of	O
salt	O
and	O
water	O
.	O
</s>
<s>
Baroreceptors	B-Algorithm
are	O
integral	O
to	O
the	O
body	O
's	O
function	O
:	O
Pressure	O
changes	O
in	O
the	O
blood	O
vessels	O
would	O
not	O
be	O
detected	O
as	O
quickly	O
in	O
the	O
absence	O
of	O
baroreceptors	B-Algorithm
.	O
</s>
<s>
When	O
baroreceptors	B-Algorithm
are	O
not	O
working	O
,	O
blood	O
pressure	O
continues	O
to	O
increase	O
,	O
but	O
,	O
within	O
an	O
hour	O
,	O
the	O
blood	O
pressure	O
returns	O
to	O
normal	O
as	O
other	O
blood	O
pressure	O
regulatory	O
systems	O
take	O
over	O
.	O
</s>
<s>
Baroreceptors	B-Algorithm
can	O
also	O
become	O
oversensitive	O
in	O
some	O
people	O
(	O
usually	O
the	O
carotid	O
baroreceptors	B-Algorithm
in	O
older	O
males	O
)	O
.	O
</s>
<s>
This	O
can	O
lead	O
to	O
bradycardia	B-Algorithm
,	O
dizziness	O
and	O
fainting	O
(	O
syncope	O
)	O
from	O
touching	O
the	O
neck	O
(	O
often	O
whilst	O
shaving	O
)	O
.	O
</s>
