blood pressure and flow Flashcards
what is compliance?
the ability of an organ to distend in response to applied pressure
what is resistance?
the ability to oppose a change
what is capacitance?
storing blood volume
what are large elastic arteries for? muscular arteries and arterioles? capillaries? veins?
large elastic arteries –> for distribution
muscular arteries and arterioles –> resistance
capillaries –> for exchange
veins –> compliance and capacitance
rank the arteries and veins from the one that has the most pressure to least.
aorta>arteries>arterioles>capillaries>venules>veins>vena cava
what is the mean aortic blood pressure in a healthy individual?
90 mmHg
a 50-70% fall in blood pressure occurs Shen the blood reaches which part of the systemic circulation and why?
when blood reaches arterioles and capillaries because they have a high resistance which means a lower blood pressure
what is the mean blood pressure in capillaries?
25-30 mmHg
does the pulmonary circulation operate at a lower or higher pressure than the systemic circulation?
lower (eventhough it has similar distribution)
what is laminar flow? turbulent flow? and does blood generally exhibit laminar or turbulent flow?
laminar flow: each particle of the fluid follows a straight line without interfering with one another and therefore the velocity is the same at any point
turbulent flow: type of flow that can be seen at branching points of blood vessels or as a result of vascular occlusion.
blood generally exhibits laminar flow
vascular endothelial cells lining the interior of blood vessels are influenced by 2 distinct hemodynamic forces. what are they?
shear stress: adhesive force that acts between blood and surface of the blood vessel that may cause damage to vessels
cyclical strain due to pressure across the vessel wall
what is shear rate?
rate at which fluid layers move past each other
how do you calculate shear stress?
shear stress = shear rate x viscosity of fluid
what is vascular resistance?
resistance that must be overcome to maintain blood flow
how do you calculate the mean blood pressure?
mean blood pressure = cardiac output x resistance
how do we calculate cardiac output?
cardiac output = stroke volume x heart rate
what are the receptors that maintains blood pressure within the limits?
baroreceptors
where are baroreceptors located?
aortic arch, carotid sinsuses, walls of vena cava and RA
what do baroreceptor do to regulate blood pressure?
send impulses to the cardiovascular centre
how do you calculate mean systemic arterial pressure ?
mean systemic arterial pressure = cardiac output x total peripheral resistance
blood pressure is recorded into two separate measurements. what are they? and when do they occur?
systolic blood pressure occurs during cardiac contraction and diastolic blood pressure occurs between heart beats when the heart is not actively contracting
how do you calculate pulse pressure?
pulse pressure = systolic pressure - diastolic pressure
what is the windkessel effect?
when blood enters aorta and other elastic arteries faster than it leaves them
what happens if arterial compliance decreases?
the windkessel effect decreases and the pulse pressure increases.
why are baroreceptors located in the aorta and the carotid arteries?
because its function is to respond quickly to pressure changes and these are highly distensible parts of the vasculature
