Regulation of Blood Pressure Flashcards
(49 cards)
how does the body sense that there has been a loss/ addition of blood volume?
baroreceptors
what 3 systems regulate MAP?
barareceptor reflex (rapid); renin-angiotensin-aldosterone system (RAAS) (slower); some input from ADH (vasopression) and ANP (slower)
what are the detectors/sensors in the baroreceptor reflex?
the baroreceptors
how do baroreceptors function?
through TRP channels that sense changes in stretch of the artery walls
what is the role of the afferents in the baroreceptor reflex?
they alter their firing rate
where is the coordinator center for the baroreceptor reflex?
in the NTS-vasomotor center in the medulla
what makes up the efferent neural pathway of the baroreceptor reflex?
both parasympathetic (vagus) or sympathetics
what is the role of the effectors of the baroreceptor reflex?
change MAP by altering CO and TPR
where are the baroreceptors located?
carotid sinus and the aortic sinus
what nerves are responsible for the carotid sinus?
the glossopharyngeal nerve (CN IX) and the sinus nerve of Hering
what nerves are responsible for the aortic sinus?
the vagus nerve (CN X) and the aortic nerve
what do the afferent neurons in the nucleus tractus solitarius utilize as their neurotransmitter?
glutamate
what do chemoreceptors respond to?
PO2, PCO2, and pH
what will be the goal if there is a decrease in pressure, decrease in stretch, and decrease in firing rate of the afferent neurons located in the baroreceptor reflex?
to increase pressure
what will be the goal if there is an increase in pressure, increase in stretch, and an increase in firing rate of the afferent neurons located in the baroreceptor reflex?
to decrease pressure
increased pressure increases firing rate and frequency of stimulation; recruitment occurs up until what in carotid bodies?
200 mm Hg
decreased pressure decreases firing rate and frequency of stimulation; signal almost vanishes at what pressure?
40-60 mmHg
what is the main difference between the sensors in the aortic vs the carotid sinus?
the aortic has a higher threshold for activation- continues to respond above saturation; the aortic sinus is less sensitive to rate- it is less affected by decreases
where is the parasympathetic activity associated with CV function located?
the dorsal motor nucleus of the vagus and the nucleus ambiguus
where is the sympathetic activity associated with CV function located?
rostral ventrolateral medulla
what are the influences of the sympathetic nervous system in the baroreceptor reflex?
the sympathetics influence the heart muscles (atria and ventricle), SA node, vessels, and the adrenal gland via the splanchnic
what 3 effects does sympathetic activity have during the baroreceptor reflex?
it will constrict the arterioles and veins via alpha-receptors; it will increase HR and contractility via beta-1 receptors; and there will be fluid retention by the kidney
how do the parasympathetics decrease heart rate during the baroreceptor reflex?
the vagus nerve signals to the SA node and through muscarinic receptors
for long term adjustments to pressure what is invoked?
a hormonal response- the Renin-Angiotensin II- Aldosterone System; ADH/ vasopressin; ANP
