Doppler Principles

Question 1

A steady, continuous stream of something.

Answer 1

Flow

Question 2

A vector quantity whose magnitude is a body’s speed and whose direction is the body’s direction of motion.

Answer 2

Velocity

Question 3

A flow with periodic variations

Answer 3

Pulsatile Flow

Question 4

A flow in which the velocity of the fluid at a particular fixed point does not change with time —called also stationary flow

Answer 4

Steady Flow

Question 5

Uninterrupted flow in a fluid near a solid boundary in which the direction of flow at every point remains constant

Answer 5

Laminar Flow

Question 6

The slipping along of a material through a conduit without plastic shear

Answer 6

Plug Flow

Question 7

The slipping along of a material through a conduit without plastic shear

Answer 7

Plug Flow

Question 8

Pertaining to flow conditions in blood vessels. Under THIS flow, blood cells in the middle of the vessels move the fastest, with a gradual decrease in flow velocity for points farther away from the center.

Answer 8

Parabolic Flow

Question 9

A fluid flow in which the velocity at a given point varies erratically in magnitude and direction

Answer 9

Turbulent Flow

Question 10

Any of several generally abnormal sounds heard on auscultation

Answer 10

Bruit

Question 11

An abnormal slight tremor associated with a heart or vascular murmur, felt on palpation

Answer 11

Thrill

Question 12

A number characteristic of the flow of a fluid in a pipe or past an obstruction

Answer 12

Reynold’s Number

Question 13

Any change in energy over time or space.

Answer 13

Energy Gradient

Question 14

Energy associated with motion

Answer 14

Kinetic Energy

Question 15

The action of pressing or pushing against something

Answer 15

Pressure

Question 16

It’s potential energy associated with the gravitational field.

Answer 16

Gravitational Energy

Question 17

The resistance to flow offered by a fluid in motion

or The friction existing between contiguous layers of fluidTHIS in blood is 5 times that of water

Answer 17

Viscosity of Fluid

Water has a low viscosity compared to molasses

Question 18

Pressure and Resistance Relationship

Answer 18

increase Pressure difference –> increases Flow
increase Resistance –> decreases Flow
increase Tube length –> increases Resistance
increase Radius –> decreases Resistance
increase Viscosity –> increases Resistance

Question 19

Hemodynamics

Answer 19

Energy losses (conversions) in vessels result from flow acceleration (increased velocity), disturbed flow, and turbulence (entrances and exits of stenotic lesions)

As these occur, the resistance of the same vascular segment increases

Question 20

Describes in the original equation that the radius of a stenosis has more effect than the length of a stenosis because the radius is raised to the 4th power

Answer 20

Poiseuille’s Law

Question 21

Narrowing of a vessel lumen

Produces disturbed or turbulent flow

Body tries to keep volume flow rate constant - proximal to, in, and distal to a ……..

This is called the Continuity Rule

Answer 21

Stenosis

Question 22

Explains that fluid moves against a pressure gradient from a point of low pressure to a point of high pressure

Total fluid energy remains the same

Pressure energy is converted to flow energy upon entrance to a stenosis

As flow energy increases, pressure energy decreases (velocity goes up; pressure goes down)

Answer 22

Bernoulli’s Principle

Question 23

Therefore, if a stenosis has an area measurement that is ½ that of the proximal and distal vessel

The average flow speed within the stenosis is twice that of the proximal and distal ends

The Doppler shift is directly related to flow speed, not volume flow rate

Answer 23

Effects of Stenosis

Question 24

The pressure that the fluid exerts on the walls of its container.

Answer 24

Hydrostatic Pressure

Question 25

The act of breathing out

Answer 25

Expiration

Question 26

The drawing in of breath; inhalation

Answer 26

Inspiration