Forms of energy and Flow Flashcards
Energy of motion
Kinetic
Kinetic energy is proportional to ____ and ____ of velocity.
It is proportional to mass and square of velocity.
Stored energy
Potential
Potential energy translates to what?
Pressure against walls: BP
What type of energy constitutes by far the greatest proportion of the overall energy?
Potential energy
What are the two components of potential energy?
- Hydrostatic pressure
2. Gravitational potential energy
Hydrostatic pressure is gravity acting on what?
Gravity acting on a column of fluid
Gravitational potential energy is proportional to what?
It is proportional to the height of a column of fluid
Hydrostatic pressure is ____ at the ____ point, where as gravitational potential energy is ____ at the ____ point in a column of fluid.
Hydrostatic pressure is highest at the lowest point. Gravitational potential energy is highest at the highest point.
Basic flow equation:
Q= ΔP
R
Another flow equation:
Q= v x CSA
Resistance equation:
R= 8Ln
πr4
If you increase the length or viscosity it causes the resistance to ____.
Increase
If you increase the radius, the resistance ____ GREATLY.
Decreases
If you double the radius, you reduce the resistance to what?
1/16
Poiseuille’s law:
Q= ΔPπr4
8Ln
Which component of Poiseuilles law has the most profound effect on flow?
Radius
What is laminar flow?
Orderly flow moving in concentric layers.
The layer next to the wall of a vessel is theoretically ____.
Motionless
Where is the fastest velocity?
Center stream
Center stream velocity is __x the mean velocity.
2x
What flow profile has the same velocities across the lumen?
Plug
In which vessels and during what part of the cardiac cycle does Plug profile occur?
It occurs:
- at the initial systolic push
- at systole in large vessels >3mm
- at entrances to stenosis
- at entrances to branching
In which vessels and during what part of the cardiac cycle does Parabolic profile occur?
It occurs:
- at late systole
- throughout cardiac cycle in small vessels < 3mm
- in diastole in large vessels >3mm
What characteristics show parabolic and plug profiles on spectral display?
Narrow range of velocities at the systolic upstroke represents plug flow, and a wider range of velocities during diastole represents parabolic flow.
What does the systolic window on spectral display represent?
Orderly laminar flow moving at a narrow range of velocities.
What type of flow is it when the systolic window is filled in?
Turbulence
What is the flow pattern in higher-resistance peripheral arteries?
Multi-phasic: having a forward, reverse, and second forward component.
Lower resistance equals ____ diastolic flow.
more diastolic flow
Higher resistance equals ____ diastolic flow.
less diastolic flow
2 characteristics of flow at bifurcations
- Flow disturbance occurs here normally (common site for plaque)
- Boundary layer of separation
In boundary layer of separation the shear forces are ____ at the flow divider, and ____ on wall away from the flow divider.
Shear forces are higher at the flow divider, and lower on wall away from the flow divider.
Faster flow is at the ____ contour.
Outer
Slower flow is at the ____ contour.
Inner
