Ch. 4 Arterial Hemodynamics Flashcards
pressure is greater where?
at the left ventricle
blood moves from areas of ___ to ___
high pressure to low pressure
blood leaves the heart with a mean pressure of ___
85-95 mmhg
where is the biggest drop in pressure?
arterioles
within the arterioles pressure will fall from app 80 down to ___
25-30 mmHG
what is the pressure at the right atrium
0 mmHG
___: how much blood is moving
flow
___: how fast the blood is moving
velocity
what is the term for flow with a constant velocity
steady flow
what is the term for flow with variable velocity due to cardiac contractions
pulsatile
what is the term for variation in velocity due to respiration
phasic flow
what are the three primary forms of energy loss as blood moves through the vessels
-friction
-viscosity
inertia
an increase in viscosity = ___ in velocity
decrease
a decrease in viscosity = __ in velocity
increase
___: smooth organized flow
laminar flow
what are the two types of laminar flow
-plug
-parabolic
which type of laminar flow is the same from wall to wall
plug flow
which type of laminar flow is slower at the vessel wall and faster in the center
parabolic flow
which flow is considered parabolic
B
which flow is considered plug
A
___: value that predicts when laminar flow becomes turbulent
Reynolds number
Reynolds number of <1500 = what kind of flow
laminar
Reynolds number >2000 = what kind of flow
turbulent
if this is the equation for resistance what does each part represent
n= viscosity
L= length
r= radius
what is the equation for resistance
if viscosity increases, resistance ___
increases
if viscosity decreased, resistance ___
decreases
if vessel length increases, resistance ___
increases
if vessel length decreases, resistance ___
decreases
if vessel radius increases, resistance ___
decreases
if vessel radius decreases, resistance ___
increase
resistance determines _____ in the arteries
rate of flow
which usually has a higher resistance blood going to the organs or blood going to the extremities
extremities
what has the greatest effect on flow resistance
vessel diameter
what happens to your resistance proximal to a stenosis, why
it will begin to increase, the vessel diameter will begin to decrease
what happens to your resistance distal to stenosis, why
begins to decrease, vessel will begin to get larger changing the diameter of the vessel
an increase in resistance would lead to a ___ in flow volume
decrease
an increase in resistance would lead to a ___ in pressure
increase
which of the following is a high restive flow pattern
1
which of the following is a low resistive flow pattern
2
___: decries how much fluid moves through a pathway
poiseuille's law
what is poiseuille's equation and what does each part represent
according to poiseuille's laws what causes the most significant changes in flow
small changes in vessel radius
if the vessel diameter decreases what happens to the velocity
increases
if vessel diameter increases what happens to velocity
decreases
describe the stenotic profile prox at and distal to the stenosis
-proximal: may or may not be altered depending of severity of snenosis and where the same is being taken
-at stenosis: increased velocity and spectral broadenign
-distal: turbulence
___: relationship between velocity and pressure
Bernoulli's principle
as velocity increases what happens to pressure
decreases
as velocity decreases what happens to pressure
increases
what is Bernoulli equation and what does each part represent
what happens to pressure and velocity at a stenosis
velocity will increase causing a decrease in pressure
what happens to the blood vessel with exercise
vasodilation
with vasodilation what happens to pressure, resistance, and volume
-pressure: decreased
-resistance: decreased
-volume: increase
___: the ability of most tissues and organs to maintain constant blood flow despite changes in perfusion and pressure
auto regulation
if BP drops what occurs
vasodilation
if BP rises what occurs
vasoconstriction
does the vessel dilate or constrict with exercise
vasodilation
what happens to resistance in extremities with exercise
turned from high resistance to low because of vasodilation
what vessel ill change from high to low after eating due to vasodilation
splanchnic
a cool limb would have what kind of flow and why
high resistance due to vasoconstriction
a warm limb would have what kind of flow and why
low resistive due to vasodilation
and increased hematocrit would have ___ viscosity
increased
anemia is the result of ___ viscosity
decreased
a delayed upstroke means a stenosis could be ____
proximal
with vasoconstriction what happens to the radius, resistance, and volume
-decreased radius
-increased resistance
-decreased volume
what re some things that cause vasoconstriction
-cold
-stress
-smoking
what are some things that can cause vasodilation
-heat
-exercise
-stenosis
at a stenos when velocity is increased what happens to the pressure
decreases
