Rest of body carotid sinus baroreceptor common

rest of body)
Carotid sinus
baroreceptor
Common
carotid arteries
(Blood to brain)
Neural signals to
cardiovascular
control center
in medulla
Aortic arch
baroreceptor
Arterial
Baroreceptors

80
Firing rate in
afferent neuron
arising from carotid
sinus baroreceptor
Arterial
pressure
(mm Hg)
Decreased Increased
Normal
120
Time
Mean
pressure
Firing rate of baroreceptor sensory neuron is directly related
to magnitude of blood pressure

Cardiovascular control center
5 components of
the reflex arc?

Blood
pressure
decreased
toward
normal
When blood pressure
becomes elevated
above normal
Carotid sinus
and aortic arch
receptor potential
Sympathetic cardiac nerve activity
and
sympathetic vasoconstrictor nerve activity
and
parasympathetic nerve activity
Heart rate
and
stroke volume
and
arteriolar and
venous vasodilation
Rate of firing
in afferent nerves
Cardiovascular
center
Cardiac output
and
total peripheral
resistance
Baroreceptor reflex in response to an elevation in blood pressure
When blood pressure
falls below normal
Carotid sinus
and aortic arch
receptor potential
Rate of firing
in afferent nerves
Cardiovascular
center
Blood
pressure
increased
toward
normal
Cardiac output
and
total peripheral
resistance
Heart rate
and
stroke volume
and
arteriolar and
venous vasoconstriction
Sympathetic cardiac nerve activity
and
sympathetic vasoconstrictor nerve activity
and
parasympathetic nerve activity
Baroreceptor reflex in response to a fall in blood pressure

Blood Pressure Abnormalities
•
Hypotension: blood pressure below 100/60 mm Hg
•
Orthostatic (postural) hypotension results from
insufficient sympathetic compensation when a person
moves from a horizontal to a vertical position
Table tilt test

Blood Pressure Abnormalities
•
Hypertension: blood pressure above 140/90 mm Hg
•
Two classes of hypertension:
•
primary hypertension- unknown cause (~90% of cases)
•
Some potential causes:
excessive salt intake, defect in salt
management of kidneys, diet, plasma membrane abnormalities, excess
vasopressin, abnormalities in vasoactive chemical signaling
•
secondary - occurs secondary to another known
primary problem (~10% of cases)

US Obesity Statistics

Hypertension medications
(angiotensin-converting-enzyme inhibitors)
Diuretics: increase urinary output
(reduce blood volume)
& others (angiotensin receptor
blockers; alpha blockers; NE
blockers, etc.)