CV intro Flashcards
what are the main “resistance vessels”?
arterioles- they determine BP, regulate what reaches capillaries/blood distribution
where is most of the blood volume in the body located?
in veins
equation for Q
Q = dP/R
Q=CO
what is dP?
Parterial - Pvenous
what is necessary for blood to flow in the proper direction in the body?
Pa > Pv
why are the aorta and pulmonary artery “elastic arteries”?
these vessels have elastic fibers that allow for recoil during diastole, this serves to maintain pressure inside of the vessel even though the heart is at rest
what is vascular compliance?
property of distensible tissue
dVolume / dPressure
what is true of vessels with high compliance?
vessels with high compliance are able to accommodate more changes in volume while resisting changes in pressure
equation for compliance in the aorta
compliance = SV x pulse pressure
equation for pulse pressure
PP = SBP - DBP
what is the consequence of low pulse pressure?
low pulse pressure indicates that there is only a small difference between SBP and DBP, this means that there will be low aortic compliance (aorta is rigid)
what is low aortic compliance a rf for?
CV disease
which vessels are typically more compliant?
veins > arteries
equation for MAP
MAP = DBP + 1/3 (SBP-DBP)
when is BP the highest?
highest right as it leaves the heart and is maintained until it reaches the arterioles when is falls drastically
what are the typical Bps for the systemic vs pulmonary systems?
systemic 120/80
pulmonary 30/10
what 2 values can be used to determine the pressure drop over the entire systemic circulation?
MAP
RAP (right atrial pressure)
change in pressure = MAP - RAP
equation for SVR
SVR = (MAP-RAP)/CO
what is the “arrangement” of blood vessels? consequence of this?
bv are arranged in parallel, this means that a change in resistance for an organ system will change flow to that organ system as well as others
resistance equation
R = 8nl/pi x r^4
resistance variables
viscosity- increase viscosity, increase R
length- increase length, increase R
radius^4- increase radius, decrease R
which resistance variable has the biggest effect?
radius
what are some situations that will increase blood viscosity?
increased hct, increased proteins in blood, sphereocytosis
what is Pouiselle’s law?
Q = dP x pi x r^4 / 8nl
increased r, increase pressure, increase flow
