Control of Blood Pressure Flashcards
what is the mean arterial blood pressure
driving force for blood flow through organs apart from the lungs
why is maintenance of blood flow essential
for ensuring adequate blood flow to the organ systems
what is arterial blood pressure usually maintained around
120/80 mmhg
when must there be variations in blood flow to different organs
when demand arises to ensure adequate prefusion
what can arterial blood pressure provide good insight into
patient’s cardiovascular health
what is blood pressure
the measure of force to push the blood around the body
how is blood pressure determined
the systolic blood pressure over the diastolic blood pressure
when is blood pressure highest
on waking
when is blood pressure the lowest
during sleep
when does blood pressure increase
exercise, stress, sensory stimuli
why should health professionals be aware of potential variability when measuring BP
it is a variable haemodynamic phenomenon
what is the systolic blood pressure
the pressure in the arteries (aorta) during myocardial contraction
what is the diastolic blood pressure
the pressure in arteries (aorta) during myocardial relaxation ie when the ventricles are refilling
how do you determine pulse pressure
minus the diastolic blood pressure from the systolic
how do you determine the mean arterial pressure
the diastolic blood pressure plus one third of the pulse pressure
how is blood pressure measured
using a sphygmomanomater
how does a sphygmomanomater measure blood pressure
occludes the artery of an extremity like the arm with an inflatable cuff and by auscilation for detection of korotkoff sounds
what is cardiac output a product of
the stroke volume and the heart rate
what is the mean systemic arterial pressure a product of
cardiac output and total peripheral resistance
what is peripheral resistance created by
the system artery
how do you determine the mean arterial pressure
the diastolic blood pressure plus one third of the pulse pressure
should there be sounds coming from an occluded artery
no, you must release some air from the cuff to allow the blood flow to reduce occlusion. this creates turbulence as the artery is not fully open, and this creates the sounds
when in the cardiac cycle is the blood pressure highest
when the blood enters the aorta on contraction of the left ventricle
what are the two mechanisms that control and regulation of blood pressure occur by
rapid regulation and long term regulation
how does rapid regulation of blood pressure occur
through nerves and hormones
what is rapid control of blood pressure initially detected by
baroreceptors
what are baroreceptors
mechanoreceptors that detect the degree of stretch of blood vessel walls and monitor blood pressure
where are baroreceptors detected
the carotid sinus and the aortic arch
what do baroreceptors sense
difference in the stretch of the vascular wall
what is stretch in the arterial walls directly related to
blood pressure
where in the heart are baroreceptors most abundant
the carotid sinus because any increases or decreases can have a big impact when it is going to the head and neck. it is also sensitive to the rate of change, not just change in stretch
where is the aortic arch
between the ascending and descending aorta
between the carotid sinus and the aortic arch, which baroreceptors must be more sensitive to changes
the ones in the carotid arch
what innervates the carotid sinus baroreceptors
the sinus nerve of hering
which arteries supply the head and neck
the carotid arteries
how do the carotid arteries divide
into two smaller arteries each - internal and external on either side
what is the carotid sinus
the area of the artery wall which is thin and contains a large number of branching nerve endings that occurs as a bulge just before they split to become internal and external carotid arteries
what innervates the aortic arch baroreceptors
aortic nerve which combines with the vagus nerve
why are the aortic arch baroreceptors less sensitive than the carotid sinus baroreceptors
they have a higher threshold pressure
describe the series of events if baroreceptors detect a decrease in arterial pressure
- reduced action potential fires from the baroreceptors
- stimulation travels along afferent neurons
- medullary cardiovascular center is located in the medulla oblongata
- increased stimulation of the sympathetic neurons to the heart, arterioles and veins
- decreased stimulation of the parasympathetic neurons from the vagus nerve to the heart
describe the series of events that follows if the baroreceptors detect an increase in arterial pressure
- increased action potential firing from the baroreceptors
-stimulation travels along the afferent neurons - medullary cardiovascular centre is located in the medulla oblongata
- decreased stimulation of sympathetic neurons to the heart arterioles and veins
- increased stimulation of the parasympathetic neurons to the heart, arterioles and veins