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Flashcards in Bruce's Fluid Dynamics Final Prep Deck (52)
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31

honey is "thick", having a

higher viscosity

32

the less viscous the fluid is, the . . . .

greater its ease of movement (fluidity).

33

State the units of viscosity

Viscosity centipoise (cP)

34

Sheer stress is directly proportional to . . .

viscosity

35

Sheer stress is inversely proportional to . . ..

the distance from the wall

36

Newtonian fluids have

a constant viscosity

37

Thixotropic fluids become

less viscus as the sheer force increases

38

Thixotropy definition

property of certain gels or fluids that are thick (viscous) under normal conditions, but flow (become thin, less viscous) over time when shaken, agitated, or otherwise stressed.

39

A thixotropic fluid displays a decrease in viscosity

over time at a constant shear rate.

40

A shear thinning fluid displays decreasing viscosity with

increasing shear rate.

41

anti-thixotropic causes:

causes an increase in viscosity or even solidification when exposed to constant shear stress for a period of time.
This property is called = rheopectic

42

Blood is often referred to as Non-Newtonian but the most appropriate term would be ?

Thixotropic

43

Smaller capillaires have greater sheer forces, what happens to the blood?

becomes less viscous

44

Roller pumps have what 3 qualities ?

-Positive displacement
-resistance independent
-predictable flow output

45

1/4" tubing =

13 ml/revolution

46

3/8" tubing =

27 ml/revolution

47

1/2" tubing =

44 ml/revolution

48

Centrifugal pumps =

Preload and afterload dependent

49

The Afterload of the centrifugal pump is determined by

everything down stream from it in the circuit:
-oxygenator,
-arterial filter
-size / length of the arterial line
-arterial cannula
-patient.

50

During Vacuum Assisted Venous Drainage (VAVD) the preload is determined by

the amount of suction in the venous reservoir

51

greater negative pressures reducing preload to the pump and thereby

reducing blood flow.

52

Safety features of centrifugal pumps

- Cannot generate extreme pressures
- deprime when challenged with large bolus of air.
-