Physics Quiz #4 Flashcards Preview

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Flashcards in Physics Quiz #4 Deck (59)
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1

Both liquids and gases are fluids?

True

2

What are the forces associated with fluids(3)?

-gravity
-pressure
-friction

3

What is friction?

-the resistance to flow from the surface interaction
-it is proportional to viscosity

4

What is viscosity?

The inherent property of a fluid that resists flow

5

What is the result of pressure forces in a fluid established by differences in pressure from one point to another, which creates a pressure gradient?

-flow
-all flow moves from higher pressure, or resistance to lower

6

What is Laminar flow?

a type of flow which all molecules of a fluid travel in a parallel path within the tube

7

Which molecules in laminar flow encounter the least adhesive force of the walls of the tube?

molecules in the center of the tube

8

Molecules in the center of the tube move at a velocity twice that of the mean flow?

True

9

True laminar flow predominates in the smallest airways(terminal bronchioles)?

True

10

What is transitional flow?

a mixture of laminar flow along the walls of the tube with turbulent flow in the center

11

What is turbulent flow?

described as chaotic with irregular eddies throughout

12

Which law is described: In straight circular tubes, the radius will have the most dramatic effect on flow = constancy X Radius to the 4th power(r^4) X pressure gradient

Poiseuille's Law

13

According to Poiseuille's law, doubling the radius will result in_____-fold increase in flow; tripling of the radius increases the flow by_____-fold?

-doubling=16 fold
-tripling-81 fold

14

Resistance is inversely proportional to r^4(the greater the radius, the smaller the resistance).

True

15

When the radius of a tube is tripled, how much will the resistance decrease?

81 fold

16

Resistance is directly proportional to fluid viscosity(the greater the blood viscosity, the greater the resistance).

True

17

Resistance is directly proportional to tube length(the longer the tube, the greater the resistance).

True

18

How are flow and resistance related?

-flow through a tube is inversely proportional to resistance
-if resistance doubles, flow is halved
-if resistance is halved, flow is doubled

19

Whose law is described: When considering flow through a tube, the gradient in hydrostatic pressure(inflow pressure minus outflow pressure) equal flow times resistance.

Ohm's Law

20

Whose law is described: MAP-CVP = CO x SVR or SVR = (MAP-CVP)/CO x 80

Ohm's Law

21

What happens to flow and what happens to resistance when the radius of the tube increases? When radius of the tube decreases?

-When the radius of a tube increases, resistance to flow decreases and flow increases
-When the radius of a tube decreases, resistance to flow increases and flow decreases

22

Is flow through 16 gauge IV catheter greater or lesser than through a 20 gauge catheter?

-16 gauge
-the greater the radius, the more flow

23

What happens to fluid flow if viscosity is increased?

flow decreases

24

Patients with polycythemia have ___ blood flow due to ___ viscosity of blood. Patients with anemia have ___ blood viscosity, hence ___ flows through tissues.

Polycythemia = decreased, greater
Anemia = decreased, greater

25

How will flow be affected when length of a tube increases? If the length of tube is decreased by 50%? If the length of a tube is doubled?

-flow will decrease
-flow will double
-flow will be decreased by half

26

If the radius of a tube decreases to 1/3 of its original size, flow will decrease to 1/81 of its original value?

true

27

Which of the following will decrease peak inspiratory pressure? 1. change ETT from 8.0 to 6.0 or 2. change ETT from 6.0 to 8.0?

changing ETT from a 6.0 to a 8.0 will decrease the PIP, PIP is greater when inflow resistance is higher and vice versa

28

These interventions are a direct manipulation of whose law: To improve flow when delivering a unit of PRBC's a large-diameter IV catheter is recommend, a pressure bag may be placed on the unit of PRBCs to increase the driving pressure(pressure gradient) and the PRBCs may be diluted with normal saline to lower viscosity.

Poiseuille's Law

29

Which factor will have the most dramatic improvement on flow: increasing the pressure, thinning the liquid(less viscous), shortening the tube, or increasing the diameter of the IV catheter?

increasing the diameter of the catheter

30

Identify 3 conditions that can change laminar to turbulent flow during anesthetic administration.

1. Gases changing direction(bend in tube of more than 20 degrees)
2. increased velocity
3. rough walled(corrugated) tubes