Arterial Hemodynamics

Question 1

blood is ejected into the arteries to maintain a ___

Answer 1

high pressure gradient between arteries and veins

Question 2

cardiac output determines ___

Answer 2

amount of blood entering the system

Question 3

arterial pressure and peripheral resistance determine ___

Answer 3

amount of blood that leaves

Question 4

venous return =

Answer 4

venous return = cardiac output

Question 5

amount of flow depends on (2)

Answer 5

energy difference
resistance

Question 6

blood moves from areas of ___ to ___

Answer 6

high energy (pressure) to low energy (pressure)

Question 7

blood leaves the heart with a mean pressure of

Answer 7

85 - 95mmHg

Question 8

arteries to arterioles pressure

Answer 8

80mmHg to 25-30mmHg

Question 9

capillaries to vein pressure

Answer 9

25-30mmHg to 10mmHg

Question 10

right atrium of the heart pressure

Answer 10

near 0mmHg

Question 11

velocity

steady flow =
pulsatile flow =
phasic flow =

Answer 11

steady = constant velocity
pulsatile = variable due to cardiac contractions
phasic = variable in the venous circulation due to respiration

Question 12

potential (pressure) energy is ___

Answer 12

stored energy in the elastic walls of arteries

Question 13

potential energy is released when ___

Answer 13

walls recoil

Question 14

potential energy (PE) =

Answer 14

PE = mgh

Question 15

kinetic energy is ___

Answer 15

movement of blood as it is ejected from the heart

Question 16

kinetic energy (KE) =

Answer 16

KE = ½mv^2

Question 17

gravitational energy (hydrostatic pressure) is very important in ___

Answer 17

venous circulation

Question 18

hydrostatic pressure when standing

Answer 18

head - 30mmHg
heart 0mmHg
waist 50mmHg
knees 75mmHg
ankles 100mmHg

Question 19

3 ways energy is loss as blood flows

Answer 19

friction
viscosity
inertia/momentum

Question 20

friction

energy is converted to ___

Answer 20

heat

Question 21

viscosity is __

Answer 21

thickness of a fluid

Question 22

increased viscosity =

___ friction
___ energy loss

Answer 22

increased viscosity =

increased friction
greater energy loss

Question 23

inertia/momentum

energy is loss when ___

Answer 23

velocity of the direction of the fluid changes
(bifurcation, stenosis)

Question 24

2 types of laminar flow

Answer 24

plug - similar flow throughout vessel
parabolic - fastest flow in the center of vessel

Question 25

what is the boundary layer?

Answer 25

layer of fluid along the vessel wall

Question 26

the boundary layer may separate from the wall resulting in ___, commonly encountered at the ___

Answer 26

eddy currants carotid bifurcation

Question 27

disturbed (non-laminar) flow may or may not be ___

Answer 27

associated with disease

Question 28

turbulent flow is associated with ___

Answer 28

disease

Question 29

Reynolds Number predicts

Answer 29

when laminar flow becomes disturbed/turbulent

Question 30

Reynolds number laminar = turbulent =

Answer 30

laminar < 1500 turbulent > 2000

Question 31

resistance formula

Answer 31

R = 8ηL / πr^4

Question 32

___ has a greater affect on resistance

Answer 32

radius/diameter

Question 33

Poiseuille's Law equation

Answer 33

Q = (P1 - P2)πr^4 / 8ηL

Question 34

Poiseuille's Law describes

Answer 34

relationship between pressure, flow, and resistance to flow

Question 35

what happens during early systole?

Answer 35

cardiac contraction, aortic valve opens high velocity ejection of blood

Question 36

what happens during peak systole?

Answer 36

aorta walls distend storing PE

Question 37

what happens during late systole?

Answer 37

rapid deceleration dicrotic notch = aortic valve closure

Question 38

what happens during early diastole?

Answer 38

temporary flow reversal

Question 39

what happens during late diastole?

Answer 39

vessels recoil converting PE to KE

Question 40

high resistance flow forward flow during ___ flow reversal during ___

Answer 40

forward flow - systole flow reversal - diastole

Question 41

low resistance flow forward flow ___

Answer 41

forward flow throughout the cardiac cycle

Question 42

area and velocity are ___

Answer 42

inversely related reduction of lumen area through stenosis results in increased velocity

Question 43

flow pattern proximal to stenosis

Answer 43

flow pattern may or may not be altered

Question 44

flow pattern distal to stenosis

Answer 44

turbulent

Question 45

hemodynamically significant stenosis = notable reduction in ___ and ____

Answer 45

notable reduction in flow and pressure

Question 46

50% diameter reduction = ___% area reduction

Answer 46

50% diameter reduction = 75% area reduction

Question 47

Bernoulli's principle decribes

Answer 47

velocity and pressure are inversely related

Question 48

arterial occlusion or stenosis may result in ___ pressure distally

Answer 48

decreased pressure distally

Question 49

distal vasodilatation maintains flow volume by

Answer 49

decreasing pressure and resistance

Question 50

peripheral resistance will change from high to low depending on (2)

Answer 50

severity demand

Question 51

hemodynamically significant stenosis may affect the speed of the pulse wave resulting in ___

Answer 51

delayed systolic acceleration time (AT)

Question 52

waveform normal peripheral artery flow

Answer 52

rapid AT systolic flow reversal minimal diastolic flow

Question 53

waveform flow-limiting stenosis

Answer 53

delayed systolic AT loss of systolic flow reversal forward diastolic flow

Question 54

waveform body cannot compensate for decreased flow

Answer 54

slow AT all diastolic flow may be lost

Question 55

___ causes a dilation or constriction of the arterioles and capillaries to maintain constant blood flow

Answer 55

sympathetic nervous system

Question 56

excellent autoregulation

Answer 56

renal arteries cerebral arteries coronary circulation

Question 57

less autoregulation

Answer 57

skeletal muscles splanchnic circulation

Question 58

little to no autoregulation

Answer 58

cutaneous circulation

Question 59

during rest, peripheral arterial bed is normally ___

Answer 59

constricted (high resistance flow)

Question 60

during exercise, the arterial bed will ___

Answer 60

dilate to allow increased blood flow (low resistance flow)

Question 61

changes in waveform morphology cannot differentiate

Answer 61

occlusion vs severe stenosis

Question 62

waveforms may not be altered with good ___

Answer 62

collateralization

Question 63

effects of disease may only be detectable following ___

Answer 63

stress (exercise)

Question 64

tissue of organ being fed by an artery determines ___

Answer 64

amount of diastolic flow

Question 65

brain and kidneys ___ metabolic rate ___ resistance flow

Answer 65

high metabolic rate low resistance flow with generous flow throughout diastole

Question 66

peripheral muscles ___ metabolic rate ___ resistance flow

Answer 66

low metabolic rate high resistance flow with little to no diastolic flow

Question 67

delay in systolic upstroke =

Answer 67

proximal stenosis