Hemodynamics Flashcards

1
Q

circulatory system is

A

closed

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2
Q

CO =

A

5 L/min

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3
Q

pressure gradient is created by

A

heart

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4
Q

RA pressure =

A

0 mmHg

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5
Q

flow occurs from ___ to ___ pressure

A

high to low

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6
Q

circulatory system is comprised of

A

heart - arteries- arterioles- capillaries - venules - veins- back to heart

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7
Q

flow is created by

A

pressure gradient

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8
Q

capacitance vessels

A

veins

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9
Q

blood makeup

A

plasma = water, protein

RBC, WBC, platelets

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10
Q

hematocrit

A

% of RBC in blood

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11
Q

flow regulating mechanisms

A

CO, cardiac function, tone + elasticity of vessels, interconnecting arterioles

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12
Q

principle point of resistance

A

interconnecting arterioles

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13
Q

regulators

A

interconnecting arterioles

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14
Q

vasomotor tone

A

constriction, dilation of vessels

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15
Q

Starlings law

A

stretch - > force of contraction of ventricles

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16
Q

HR is affected by

A

baroreceptors, chemoreceptors, exercise

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17
Q

Windkessel effect

A

elasticity of vessel, wall compliance, tone

reflection of wave back up vessel wall, creates dicrotic notch

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18
Q

arterial pulse pressure wave

A

pressure wave is propagated throughout arterial tree with each contraction of heart.
pressure wave velocity increases as it moves into smaller, stiffer peripheral arterioles

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19
Q

times it takes for pressure wave to travel from heart to foot

A

250 ms

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20
Q

arterial pulse pressure wave occurs in

A

vessel wall, independent of blood

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21
Q

volume flow

A

volume of blood passing a point per unit of time

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22
Q

adult blood flow rate

A

5 L/min

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23
Q

Q =

A

(A) X (TAV)

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24
Q

Continuity rule

A

volume in closed system must stay constant. Blood volume is not lost or created (conservation of matter)

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25
Q

Continuity rule in case of stenosis

A

since the same volume of blood must pass, but the area is smaller, the velocity therefore must increase

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26
Q

Continuity equation

A

A1V1 = A2V2

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27
Q

if area is halved, then velocity is

A

doubled

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28
Q

a change in area affects

A

pressure and flow

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29
Q

density of blood

A

1.05 g/mL

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30
Q

viscosity of blood

A

0.035 poise

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31
Q

viscosity is created by

A

internal frictional forces within the fluid

32
Q

viscosity of blood is affected by

A

hypothermia, polycythemia, severe anemia

33
Q

Q =

A

delta P/ R

34
Q

if resistance increases, Q ____

A

decreases

35
Q

if pressure gradient increases, Q ____

A

increases

36
Q

Poiseuille’s law

A

describes flow through a tube

37
Q

Poiseuille’s law states that flow is related to

A

viscosity, radius, length, pressure gradient

38
Q

greatest factor in Poiseuille’s law affecting flow is

A

radius/diameter

39
Q

if diameter in stenosis is 1/2 the original lumen, the flow will be reduced ___ times

A

16 times

r^2

40
Q

increase in viscosity will ___ resistance

A

increase

41
Q

increase in tube length will ___ resistance

A

increase

42
Q

increase in diameter will ___ resistance

A

decrease

43
Q

decrease in diameter will ___ resistance

A

increase

44
Q

2 types of fluid energy

A

potential, kinetic

45
Q

E total =

A

E potential + E kinetic

46
Q

potential energy is

A

intravascular pressure and gravitational potential energy

47
Q

kinetic energy is

A

related to motion of blood

48
Q

Bernoulli principle

A

increase in velocity of fluid occurs simultaneously with a decrease in pressure or potential energy

49
Q

pressure and velocity are ___ related

A

inversely

50
Q

when blood accelerates/decelerates energy is

A

converted back and forth from potential to kinetic anc back

51
Q

an increase in velocity will cause a ___ in P

A

decrease

52
Q

parabolic flow profile

A

laminar flow, speed varies across tube, highest in center, slowest at edges,

53
Q

average velocity in laminar flow

A

= 1/2 max speed

54
Q

plug flow

A

laminar flow, flattened parabola, more uniform in speed

55
Q

plug flow is usually found in

A

large vessels, at branch points

56
Q

jet flow

A

high velocity at narrowing

57
Q

disturbed flow

A

mild turbulence

58
Q

disturbed flow occurs at

A

bifurcations, curves, near heart

59
Q

turbulent flow

A

non-linear, multiple directions and velocities,

60
Q

turbulent flow is found at

A

distal to stenosis

61
Q

Reynolds number

A

predicts turbulence

62
Q

Reynolds number =

A

> 2000 = turbulence

63
Q

Reynolds number =

A

[average flow speed x tube diam x density ] / viscosity

64
Q

2 patterns of pulsatile flow

A

high res, low res

65
Q

organs supplied by low res

A

essential for life, need constant perfusion

66
Q

RI =

A

A-B / A

67
Q

PI =

A

A- B / mean

68
Q

S/D

A

PSV /EDV

69
Q

BOUNDARY layer

A

layer of fluid in which the surface of the vessel wall has exerted its influence by means of viscous drag

70
Q

velocity at boundary layer

A

0 at wall

71
Q

boundary layer separation

A

free boundary between layers of fluid moving in opposite directions, can be found in carotid bulb

72
Q

flow preceding stenosis

A

slows down

73
Q

flow at stenosis

A

jet

74
Q

flow after stenosis

A

turbulence

75
Q

flow further after stenosis

A

tardus parvus

76
Q

Reynolds

A

effects of change of diameter and speed on fluid flow patterns

77
Q

most common variant of aortic arch

A

bovine arch = common origin of brachiocephalic/innominate and LCCA