###
-The Doppler Effect is explained by a change in ____ due to ____ of the ____ or ____

-There is also a change in ____

-frequency, motion, sound source, reflector

-wavelength

###
-A reflector moving towards the source leads to an ____ in frequency

-A reflector moving away from the source leads to a ____ in frequency

-increase (positive shift)

-decrease (negative shift)

### Doppler shift is the difference between?

the frequency going into the body and the frequency returned to the transducer

###
Blood Flow:

-blood is composed of? (4)

-blood is about ___% cells

-plasma, erythrocytes, leukocytes, and platelets

-40 (hematocrit)

###
-If your hematocrit is too low what will happen? (hypovolemia)

-If your hematocrit is too high what will happen? (hypervolemia)

-bleed

-clot

### Fluid Characteristics: Density is

Mass per unit volume

--Mass: An object's resistance to acceleration

###
Fluid Characteristics: Pressure

-pressure is Equally exerted in all directions in a ____ fluid (omnidirectional)

-A pressure difference is required for

-Increased pressure difference, ____flow rate

-Flow travels from the ____ to the ____ pressure-end

-static

-flow to occur

-increased

-higher, lower

###
Volume Flow Rate is the

-measured in

-determined by

Volume of blood that passes a given point per unit time

-mL/m (or s)

-pressure difference and resistance to flow (If resistance increases, volume flow rate decreases)

###
Volume Flow Rate:

-Flow resistance is determined by

-the formula is

-Poiselle's Law (or a variant of it)

-FR = 8 X Length X viscosity/ p X r^4

###
Volume Flow Rate:

-Flow rate is determined by

-flow rate depends on what 4 things?

-Poiselle's Law

-pressure difference, vessel length, vessel diameter and fluid viscosity

###
Poiseuille's Law:

Q = Quantity of blood

π = constant (3.14)

p = pressure difference

r = vessels radius

l = vessel length

n = blood viscosity

-Quantity of blood

-constant (3.14)

-pressure difference

-vessels radius

-vessel length

-blood viscosity

###
Flow Resistance Relationships:

-Increase tube length, ____ resistance

-Increase viscosity, ____ resistance

-Increase tube (vessel radius), ____ flow resistance

-increase

-increase

-decrease

###
Flow Rate Relationships:

-Increase pressure difference, ____ flow rate

-Increase diameter, ____ flow rate

-Increase vessel length, ____ flow rate

-Increase viscosity, _____ flow rate

-increase

-increase

-decrease

-decrease

### Plug flow: where is blood flow faster and slower?

very slow at the walls, but still faster in the center

###
Blood Flow: Shape depends

-small and medium vessels produce a ____ shape.

-larger vessels produce a ____ or ____ flow shape.

vessel size

-parabolic

-plug or blunted flow- fairly constant flow speed across vessel

###
Laminar Blood Flow:

-Occurs in a ____ substance

-____ substance

-non uniform flow velocities fastest in

-fluid

-viscous

-center of vessel

###
Laminar Blood Flow:

-non uniform flow velocities with flow faster in the center of vessel occurs due to

-viscous drag

-friction

###
Parabolic Blood Flow:

-Steady, laminar flow in a ___ & ___ tube

-Does or doesn't occur very often in the body? Because?

-long and straight

-doesn't because vessels are not long enough

###
Disturbed Flow:

-____ streamlines are altered

-Occurs at ____ or ____

-Flow is still in the ____ direction

-A type of ____

-Is disturbed flow an indicator of pathology?

-parallel

-bifircations or stenosis

-forward

-laminar

-not nessecarily

###
Turbulent Flow:

-The direction of this flow is

-circular flow is called

-where would you see turbulant flow?

-in many directions (chaotic and random), but remains forward overall

-eddie currents

-distal to Dx

###
Turbulent Flow:

-The flow speed at which turbulent flow occurs is determined by the ____

--which is dependent upon ____ and ____ of fluid and ____ of tube

-Reynolds number

-density, viscosity, diameter

###
Reynold's Number:

-formula?

-A reynold's number above ____ indicates turbulence

-R = average flow speed X tube diameter X density/viscosity

-2000 (Critical reynold's number)

###
Pulsatility:

-is the ability of a structure to

-depends upon

-allows for

-expand and contract

-stroke volume, ventricular ejection time, peripheral resistance and vascular compliance

-flow reversal

###
The Continuity Rule:

-states that volume flow rate remains

-the continuity rule =

-if vessel lumen is decreased, flow speed at areas of stenosis will ____

-constant throughout a vessel

-average flow speed X cross sectional area of the vessel

-increase

###
The Continuity Rule:

-Expressed with a variant of Poiselle's Law:

-Doppler shift is directly related to

-Average flow speed = Pressure difference X diameter2/ 32 X Length X viscosity

-flow speed

###
Poiselle's Law vs. The Continuity Equation:

-Poiselle's Law: deals only with ____

-which means no ____

-as diameter decreases, flow speed ____

-long straight vessels

-stenosis

-decreases

###
Poiselle's Law vs. The Continuity Equation:

-Continuity Rule: describes a

-as diameter decreases, flow speed ____

-short (stenotic) region of a vessel

-increases

###
Bernoulli's Equation:

-All KE, PE and work are ____

-Energy is lost through ____

-conserved

-friction (changed to heat (inertial loss))

***p + rgh + 1/2 rv2 = B

###
Bernoulli's Equation:

-Pressure at a region of stenosis is less than

-As flow energy increases, pressure energy ____

-A drop in pressure associated with high flow speeds at a ____

-proximal or distal to that region

-decreases

-stenosis

###
Arterial vs. Venous Flow:

Pulsatility vs. Respiratory Changes

-Arteries have a higher or lower pressure than veins?

-wall composition

-higher

-Internal Elastic Lamina, External Elastic Lamina

###
Hemodynamics:

-Intravascular Pressure

-Cardiac Output

-heart contraction

static filling

hydrostatic pressure

-volume per minute

###
Venous Flow:

-are veins more muscular or elastic?

-As resistance in peripheral arteries increased venous return ____

-Vary with ____ and show ____ changes

-larger veins will have ____

-muscular

-decreases

-pressure, respiratory

-valves

###
Flow Variations:

-Normal flow is considered

-As lumen size increases you can what kind of flow?

-Also as lumen size increases, you can get varied flow patterns (3)

-laminar

-plug flow (more uniform velocities)

-eddy flow

high velocity flow

stagnant flow

###
Flow Variations:

-As vessels turn the velocities will be higher where?

at the outer edges of the vessel

###
Resistive Index:

-the resistance of the distal ____ ____ to fill with blood

-RI=

-anything less than ___ is low resistance, and anything above ___ is high

-capillary bed

-Ps - Ed/ Ps

-0.7, 0.7

###
Resistance:

-the less capillaries available, the ____ resistance and the ____ the RI

-high resistance signals lack ____ flow or have ____ diastolic flow

-more, higher

-diastolic, reverse

###
Flow Variations:

-As vessels near critical stenosis you may see ____ ____

--filling in of the ____ ____

--velocities are increased or decreased?

-spectral broadening

--systolic window

-increased

###
Flow Variations: As vessels stenoes

-effects vary with degree of ____ and normal vessel ____

-effects do not affect hemodynamics until about ___% stenosis

-If a vessel started as low resistance generally the vessel loses ____ flow as pathology worsens

-stenosis, characteristics

-60

-diastolic

###
Pulsatility:

-applies to ____ only

-describes the amount of ____ of walls

-PI=

-arteries

-elasticity

-Ps - Ed / mean velocity

###
The Doppler Effect:

-Changes in relative motion are seen as changes in ____

-Scanning angle should be as ____ to vessel as possible

-FREQUENCY

-parallel

###
The Doppler Effect:

-The Fd =

-the frequency difference is measured in ___ and the inital and returned frequency are measured in ___

-F r - F i

-KHz, MHz

###
The Doppler Equation: Relationships

-Increase Fd, ____ scatter speed

-Increase Fo, ____ scatter speed

-Increase Cos, ____ scatter speed

-increase

-decrease

-decrease

###
The Doppler Equation:

-As angle goes up the cos of the angle goes

-Cos 90 =

-Cos 0 =

-Increase Doppler angle, ____ scatter speed

-down

-0

-1

-increase

###
Doppler Ultrasound:

-Set angle between ____ degrees

-Largest Doppler return at ___ degrees

(Cannot determine forward vs. reverse flow)

-No Doppler return at ___degrees

-30-60

-0

-90