Hemodynamics Flashcards

1
Q

Hemodynamics is the study of what?

A

blood moving through the circulatory system.

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2
Q

What is flow?

A

aka: volume flow rate

indicates the volume of blood moving during a particular time.

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3
Q

Flow answers what question?

A

How much

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4
Q

Flow answers what question?

A

How much

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5
Q

what does velocity indicate?

A

the speed of moving fluid from one location to another.

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6
Q

Velocity answers what question?

A

how fast

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7
Q

What are the 3 basic forms of flow

A
  1. pulsatile
  2. phasic
  3. steady
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8
Q

what is pulsatile flow?

A

blood flow with a variable velocity.

As a result of cardiac contraction

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9
Q

What is phasic flow?

A

as a result of respiration

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10
Q

Steady flow is what?

A

fluid moving at a constant speed.

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11
Q

What are the 2 forms of laminar flow?

A
  1. Plug flow
  2. parabolic flow
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12
Q

What is plug flow

A

all layers of blood travel at the same velocity.

Often seen at the beginning of vessels.

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13
Q

what is parabolic flow?

A

velocity is highest in the center of the lumen.

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14
Q

What does the reynolds’s number predict?

A

whether flow is laminar t or turbulent.

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15
Q

what reynolds’s number predicts turbulent flow?

A

<2000

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16
Q

turbulent flow is often characterized by what?

A

chaotic flow patterns in many different directions and speed.

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17
Q

What is a sound associated with turbulence?

A

murmur or bruit

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18
Q

What is a vibration associated with turbulence?

A

A thrill

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19
Q

blood moving from regions of higher energy to lower is called what?

A

an energy gradient

20
Q

What are the three forms of energy?

A
  1. Kinetic
  2. Pressure
  3. gravitational
21
Q

kinetic energy is associated with what?

A

a moving object

22
Q

Pressure energy is a form of what?

A

stored or potential energy

23
Q

Potential energy has the ability to do what?

A

Perform work

24
Q

gravitational energy is associated with what?

A

any elevated object

25
Q

What are the 3 ways energy is lost through circulation?

A
  1. viscous loss
  2. frictional loss
  3. inertial loss
26
Q

what is viscous energy loss?

A

has to do with the thickness of blood

27
Q

In what 3 ways does inertia energy loss happen?

A
  1. pulsatile flow
  2. phasic flow
  3. velocity changes at a stenosis
28
Q

What are 5 effects of a stenosis?

A
  1. change in flow direction
  2. increased velocity as vessel narrows
    3 turbulence downstream from the stenosis
  3. pressure gradient across the stenosis
  4. loss of pulsatility
29
Q

Bernoulli describes the relationship between what?

A

between velocity and pressure in a moving fluid

30
Q

What is the law of conservation of energy

A

energy is neither created nor destroyed.

States that pressure energy is lowest wherever the kinetic energy is the highest, at the narrowest part of the lumen.

31
Q

What is the formula for pressure gradient?

A

Pressure gradient=flow x resistance

32
Q

What is the relationship between pressure gradient and flow/resistance?

A

Directly.

When Pressure gradient increases, flow and resistance increases.

33
Q

What is hydrostatic pressure?

A

pressure related to the weight of blood pressing on a vessel.

34
Q

What is the hydrostatic pressure of a supine individual?

A

0

35
Q

what is the formula for measured pressure?

A

Measured pressure= circulatory pressure + hydrostatic presure.

36
Q

What is the arterial pressure measured in the toe of the upright patient?

A

240mmHG
Hydrostatic pressure= 100mmHG
Pressure generated by the heart is 140 mmHG
100+140=240mmHG

37
Q

What is the arterial pressure measured at the standing patients upper arm?

A

140mmHG
Hydrostatic pressure = 0mmHG
Pressure generated by the heart = 140mmHG
0+140=140mmHG

38
Q

What is the arterial pressure measured at the finger when the patient fully extends an arm toward the sky?

A

90mmHG
Hydrostatic pressure= -50mmHG
Pressure generated by the heart= 140mmHG
-50+140=90mmHG

39
Q

Normally, what happens to venous flow in the legs during inspiration?

A

Venous flow in the legs decreases.

40
Q

What is the primary reason blood moves from on location to another?

A

energy gradient

41
Q

Which of the following causes the greatest amount of inertial energy loss?
pulsatile flow
flow through a stenosis
phasic flow
steady flow
parabolic flow

A

Flow through a stenosis

flow through a stenosis causes the greatest velocity changes and greatest inertial loss.

42
Q

What happens to the diaphragm when an individual breathes in?

A

diaphragm descends into the abdomen

43
Q

What happens to venous return to the heart when an individual inhales?

A

venous return to the heart increases.

44
Q

What happens to venous flow in the legs during inhalation?

A

Venous flow in the legs decreases

45
Q

What happens to the diaphragm when an individual breathes out?

A

It moves up into the chest cavity

46
Q

What happens to venous return to the heart during exhalation?

A

Venous return to the heart decreases.