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ULTRASOUND PHYSICS > Ch 18 > Flashcards

Ch 18 Flashcards

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1
Q

The loss of fluid energy through inertia
a. Is best described by Poiseuille’s Law
b. Is greatest in a large tube with high velocity flows
c. Explains less energy loss than viscous losses
d. Is greatest in vessels that change directions with multiple stenoses

A

D

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2
Q

Which of the following does not apply to turbulent flow?
a. Is affected by velocity
b. Produces murmurs, bruits, and thrills
c. Occurs at abrupt changes in vessel diameter
d. Can be predicted by the Reynolds number
e. Causes increased pressure downstream

A

E

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3
Q

Which of the following refers to arterial flow reversal during diastole?
a. Is found in the internal carotid artery
b. Is found in and proximal to high-resistance areas of flow
c. Is most common in vessels with low-resistance beds
d. Is always an abnormal waveform

A

B

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4
Q

If the artery has a reduction of 90% by cross sectional area measurement, the equivalent diameter reduction is
a. 25%
b. 30%
c. 50%
d. 75%
e. 90%

A

D

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5
Q

The waveform in a collateral vessel is high resistance compared to the normal artery on the opposite (contralateral) side. The increased resistance may be caused by
a. Decreased resistance in the vascular bed
b. Increased vessel length
c. Decreased tube diameter

A

B&C

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6
Q

After walking exercise, the venous pressure at ankle level of a person in the standing position
a. Is higher than the standing ankle pressure at rest
b. Is lower than the standing ankle pressure at rest
c. Is the same as standing ankle pressure at rest

A

B

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7
Q

Your patient has edema (swelling from water retention) in the lower right extremity. This may be caused by
a. Increased intravenous pressure
b. Decreased venous hypertension
c. Increased venous hypovolemia

A

A

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8
Q

What term relates to the point at which flow becomes turbulent?
a. Bernoulli’s Principle
b. Poiseuille’s Law
c. Reynolds number
d. Law of Conservation of energy

A

C

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9
Q

What is the maximum velocity limit to report the Doppler shift for a 3 MHz CW Doppler probe at 4 cm depth?
a. 30 cm/sec
b. 200 cm/sec
c. 2.5 m/sec
d. None of the above (CW Doppler do not alias and do not have this limitation)

A

D

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10
Q

In which situation is turbulence most likely to occur?
a. 5 mm vessel with 300 cm/sec velocity (higher velocity’s and larger diameters increase the Reynolds Number)
b. 2 mm vessel with 300 cm/sec velocity
c. 2 mm vessel with 30 cm/sec velocity
d. 1mm vessel with 20 cm/sec velocity

A

A

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11
Q

The most numerous of the blood cells are
a. Lymphocytes
b. Erythrocytes
c. Platelets
d. Leukocytes

A

B

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12
Q

The Reynolds number increases with increasing
a. Flow velocity
b. Viscosity
c. Vessel diameter
d. All of the above

A

D

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13
Q

. The Principle that states that the volume of flow must be the same before, during and after a stenosis is
a. Continuity rule
b. Poiseuille’s Law
c. Bernoulli effect
d. Reynolds Number
e. Nyquist limit

A

A

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14
Q

The principle that states that the pressure decreases when the velocity increases is
a. Continuity rule
b. Poiseuille’s Law
c. Bernoulli effect
d. Reynolds Number
e. Nyquist Limit

A

C

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15
Q

What Reynolds number would indicate turbulent flow?
a. 200
b. 2,000
c. 300
d. 3,000

A

B&D

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16
Q

Parabolic flow is most likely found in which situation?
a. Small veins
b. Disturbed flow areas
c. Where aliasing is occurring
d. In laminar flow areas

A

D

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17
Q

When the streamlines of flow are parallel, the flow is called
a. Parabolic
b. Laminar (plug flow is also laminar)
c. Disturbed
d. Turbulent

A

B

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18
Q

Poiseuille’s equation indicates that if the pressure gradient increases
a. Flow rate will increase
b. Flow rate will decrease
c. Flow will become more pulsatile
d. Flow will become more turbulent

A

A

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19
Q

Which statement best applies to cardiac output?
a. It is the hydrostatic pressure at heart level
b. It is the maximum velocity in the heart vessels
c. It is the quantity of blood moving through the heart
d. It is the volume of blood pumped from the heart per minute

A

D

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20
Q

The volume of flow can be determined by multiplying the cross sectional area and
a. The peak velocity
b. The mean velocity
c. The volume flow rate
d. Velocity range

A

B

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21
Q

The part of the vessel wall that is a single layer of cells backed by a thin layer of elastin and collagen is
a. Intima
b. Media
c. Adventitia
d. Venous valves

A

A

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22
Q

When red blood cells cling together to form clumps in areas of slow flow it is called
a. Rayleigh scattering
b. Newtonian fluid
c. Rouleaux formation
d. Huygen’s principle

A

C

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23
Q

A color bruit will most likely be imaged when there is
a. Very slow flow in a small vessel
b. Chronic occlusion
c. Turbulent flow distal to a significant stenosis
d. High velocity normal arterial flow

A

C

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24
Q

If a patient has normal arterial waveforms with low velocities in the vessels, which is most likely?
a. Low cardiac output
b. Low red blood cell count (Hematocrit)
c. Hypertension (High BP)
d. Hypotension (Low BP)

A

A

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25
Q

Which of the following is NOT found in normal veins?
a. Spontaneous flow
b. Phasic flow
c. Pulsatility
d. Compressibility

A

C

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26
Q

Veins and arteries are different in all of the following EXCEPT
a. Veins are divided into deep and superficial systems
b. Veins are collapsible
c. Veins are distensible
d. Veins have thicker walls with a very little muscle

A

D

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27
Q

The outermost layer of the vessel wall is
a. Tunica adventitia
b. Tunica media
c. Tunica intima
d. Endothelium

A

A

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28
Q

A normal venous signal is described as
a. Continuous
b. Pulsatile
c. Phasic
d. Irregular

A

C

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29
Q

During inspiration (inhale) the intra-abdominal (below the diaphragm) pressure _______ so venous flow _____
a. Increases, decreases
b. Increases, increases
c. Decreases, decreases
d. Decreases, increases

A

B

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30
Q

The pressure within a vein is
a. Indirectly proportional to the cardiac output
b. Equal to the arterial pressure
c. Directly proportion to the force on the vein wall from the blood volume in the vein
d. Directly proportional to the rate of respiration and the pulmonary health

A

C

31
Q

The normal dynamic venous pressure in the venules is 15 to 20 mmHg. What is the pressure in the rt atrium?
a. 50 mm Hg
b. 0 mmHg (within the rt atrium and is called the central venous pressure)
c. 100 mmHg
d. 15-20 mmHg

A

B

32
Q

Normal venous characteristics include all EXCEPT
a. Spontaneity
b. Compressibility
c. Continuous signal through respiration
d. Phasicity

A

C

33
Q

The principle that states that blood flow from one point to another because of an energy gradient and is slowed by resistance is
a. Bernoulli’s principle
b. Poiseuille’s Law
c. Reynolds Lay
d. Law of Continuity of Energy
e. The Doppler equation

A

B

34
Q

Venous valves are formed in which layer?
a. Adventitia
b. Media
c. Intima
d. Endothelial tissue

A

C

35
Q

The physiology of circulation is called
a. Fluid dynamics
b. Circulatory system
c. Hemodynamics
d. Blood flow and pressure gradients

A

C

36
Q

Blood flow in concentric layers with the highest velocity in the center of the vessel is
a. Laminar flow
b. Disorganized flow
c. Boundary layer separation
d. Turbulent flow

A

A

37
Q

Following a significant stenosis, the swirling motion is called
a. Collateral flow
b. Vortices (also called eddies)
c. Reversed flow

A

B

38
Q

Which of the following is NOT true about the Reynolds number?
a. Explains the point where flow changes from laminar to disturbed
b. Is less than 2000 in normal arterial flow
c. Predicts the stability of a fluid
d. Is not included in the principles of fluid dynamics

A

D

39
Q

Turbulence in flow following (distal to) a narrowing in the vessel is
a. Poststenotic turbulence
b. Velocity jet
c. Dampened flow
d. Bernoulli flow

A

A

40
Q

Laminar flow becomes disturbed when the Reynolds number is higher than
a. 500
b. 1000
c. 1500
d. 2000
e. 3000

A

D

41
Q

The velocity of flow is __________ related to the cross sectional area (size) of a vessel
a. Inversely
b. Directly
c. Not related
d. Varies with other factors

A

A

42
Q

Blood pressure is
a. The flow volume going through the arteries
b. Average pressure throughout the cardiac cycle
c. Pressure of the blood on the vessel wall
d. Pulse pressure in the circulation

A

C

43
Q

Exercise usually ___________ flow
a. Increases
b. Decreases
c. Does not change
d. Depends on the size of the person

A

A

44
Q

The anatomy of arteries includes all of the following EXCEPT
a. Intima
b. Media
c. Adventitia
d. Internal capsule

A

D

45
Q

Which term describes the contraction or narrowing of the vessel lumen?
a. Vasodilatation
b. Vasoconstriction
c. Stenosis
d. Vasospasm

A

B

46
Q

Blood flow and pressure are not significantly compromised until _______ of cross sectional area is eliminated?
a. 25%
b. 50%
c. 75%
d. 95%

A

C

47
Q

Factors that influence a critical stenosis are
a. Length of the stenosis
b. Blood viscosity
c. Peripheral resistance
d. All of the above

A

D

48
Q

The resistive index is used to quantify
a. Arterial flow
b. Venous flow
c. Resistance
d. Turbulence

A

C

49
Q

Which layer of the artery is the muscle layer?
a. Intima
b. Media
c. Adventitia
d. Endothelium

A

B

50
Q

The principle factors affecting blood volume changes are
a. Viscosity and vessel diameter
b. Cardiac output and peripheral resistance
c. Pressure gradients and inertial loss
d. Energy loss and flow-reducing stenoses

A

B

51
Q

The highest systolic velocity is located at
a. The narrowest portion of the stenosis
b. Just preceding the stenosis
c. Immediately distal to (following) the stenosis

A

A

52
Q

The artery with the smallest radius will have _____ if the other factors are all the same.
a. Lower resistance to flow
b. Higher resistance to flow (as radius decreases, resistance increases)
c. No difference in resistance
d. Variable resistance depending on distance from the heart

A

B

53
Q

Flow information from a specific location is obtained by using the
a. Velocity range
b. Doppler angle
c. Angle correct
d. Sample volume of the range gate

A

D

54
Q

The flow velocity in an artery normally accelerates
a. Slowly
b. Moderately
c. Rapidly
d. Varies with standing or supine positions

A

C

55
Q

The property of fluid that causes resistance is
a. Temperature
b. Viscosity
c. Inertia
d. Elasticity

A

B

56
Q

Resistance to acceleration is called
a. Resistance
b. Viscosity
c. Inertia
d. Impedance
e. Density

A

C

57
Q

Flow is a response to pressure ________ or __________
a. Difference, gradient
b. Values, hydrostatic pressure
c. Measurements, gravity

A

A

58
Q

The direction of flow is from _________ to _____________
a. More gravity to less gravity
b. More height to less height
c. Higher pressure lower pressure

A

C

59
Q

Which of the following causes an increase in flow?
a. Increase pressure difference
b. Increased pressure gradient
c. Increased resistance
d. A and b
e. All of the above

A

A&B

60
Q

As resistance increases, flow rate
a. Increases
b. Decreases
c. Is not affected

A

B

61
Q

If the pressure difference is doubled, the flow rate is
a. Doubled
b. Increased 4 times
c. Halved
d. Is not affected

A

A

62
Q

If resistance is doubled, the flow rate is
a. Doubled
b. Increased 4 times
c. Halved
d. Is not affected

A

C

63
Q

Resistance to flow is a response to
a. Vessel length
b. Vessel radius
c. Blood viscosity
d. All of the above

A

D

64
Q

Flow resistance decreases with an increase in
a. Vessel length
b. Vessel radius
c. Blood viscosity
d. All of the above

A

B

65
Q

Flow resistance depends most significantly on which of the following?
a. Vessel length
b. Vessel radius
c. Blood viscosity
d. All of the above

A

B

66
Q

Doubling the vessel radius decreases its resistance to ____ of the original value.
a. One half
b. One fourth
c. One eight
d. One sixteenth (radius to the fourth power R = 8Ln / pi r4) see og 105 in review Ch 4

A

D

67
Q

Volumetric flow rate decreases with an increase in
a. Pressure gradient
b. Vessel radius
c. Vessel length
d. Blood viscosity

A

C&D

68
Q

When the speed of the fluid is constant across the vessel, the flow is
a. Laminar
b. Parabolic
c. Plug
d. Viscous

A

C

69
Q

As the diameter decreases at a stenosis, the following pass through a maximum.
a. Flow speed at the stenosis
b. Flow speed proximal to (before) the stenosis
c. Volumetric flow rate
d. Doppler shift at the stenosis
e. A and d

A

E

70
Q

Flow reversal and additional forward flow (rebound) occur with
a. Turbulent flow
b. Pulsatile flow
c. Phasic flow
d. Disturbed flow

A

B

71
Q

In a stenosis, the pressure is ______ the values proximal and distal to the stenosis
a. Less than
b. More than
c. Equal to
d. Depends on the viscosity

A

A

72
Q

The Continuity Rule says that flow speed __________ with decrease in diameter (stenosis)
a. Increases
b. Decreases
c. Is not affected
d. Depends on viscosity

A

A

73
Q

Poiseuille’s equation predicts that flow speed ____________ in a stenosis
a. Increases
b. Decreases
c. Is not affected
d. Depends on viscosity

A

A

74
Q

Proximal to, at, and distal to a stenosis, what must be constant?
a. Velocity
b. Volumetric flow rate
c. Pressure gradients
d. Flow profiles

A

B

ULTRASOUND PHYSICS (7 decks)

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