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Flashcards in Cv 2 Vessels Deck (56):
1

When BP changes in respect to arterioles changing size

If 1 changes BP wont change. If all change- constrict, BP up, all relax, bp down

2

How much relative blood volume in veins

2/3

3

Why high CO is issue in anemia

Already low 02, high CO will lead to less time spent for oxygen exchange

4

Biggest players in vascular resistance and why

Arterioles- control flow

Capillaries- small size

5

Which organs get most flow (Q)

Heart 4%, but uses larger proportion of it than brain (gets 13%)

Liver and GI 24%, liver filters

Muscle 21%, increases if running

Kidney 20%, filters

Skin 18%

6

Which organs use 02 the most VO2

Brain, 21%. Uses less than heart per proportion (heart 11%)

Kidney is active, liver and gi average, skeletal muscle average

7

When running where does CO leave and go to

Leaves liver and GI, goes to muscles

8

How to calculate map:

P___ + (__-___ / ___)

Pdiastolic +

Systolic- diastolic
___________________
3

9

Can never have higher pressure on average higher than where

Inside of heart, farther away from hydrostatic pressure and lose it to gravity

10

Big drop in average pressure where

Small pressure drop

Almost no pressure drop

Arterioles

Capillaries

Veins

11

What is poiseueille's law

R (resistance)=
N (viscosity) x L (tube length) x 8
____________________________
Pi x r (radius) ^4

12

Relationship to resistance

Radius

Tube length

pressure difference

Radius inc- less resistance, dec more resistance

Longer tube will have more resistance

More pressure difference less resistance.

13

What happens as radius doubles

Flow increases to a factor of 16 (r to 4th)

14

What happens as tube length doubles to flow

Flow cut in half, flow= 1/length

15

Flow= __ x ___ x __

Height of column
Density
Acceleration of gravity

16

What happens when height of one tube twice as high as other

Pressure twice as great, twice as much flow

17

What happens when tubes have same height of fluid (effect on flow)

Pressure difference is 0 so flow is 0

18

Flow in tube with length 1 vs tube with length 2

Flow twice as great in flow with length 1

19

What happens to flow as viscosity doubles

Flow cut in half

20

What happens when we double radius to flow

Increase flow by factor of 16

21

Where radius changes play into effect in physiology

When radius isn't a limiting factor

Small changes in arterioles have big changes in flow and resistance downstream.

When volume isn't full (flow of blood through vessel is limiting factor)

22

What happens to viscosity as hct increases

Viscosity increases

23

How SVR impacted by hematocrit

Less hematocrit= easier to push= less SVR

Opposite for more SVR

Overall effect of viscosity

24

What impacts viscosity in different areas of the body

What is lowest possible viscosity of blood

Size of the vessel

Small tube- rbcs line up better, less viscosity than in larger tube

Same as plasma but has to be higher than that

25

Resistance through network is what in series

Same as the sum of the individual resistors

26

Resistance through network is what when in parallel

Sum of the reciprocal of the individual resistances

27

Relationship between velocity and area in vessels

Velocity is inverse of area

28

Which cross sectional area bigger: aorta or sum of its branches

Sum of its branches

29

What happens to velocity as aorta goes into branches

What happens to velocity as capillaries form into veins

Velocity decreases, surface area increases

Velocity increases, surface area decreases

30

Purpose of velocity decrease in capillaries

Spends more time there, better for diffusion

31

Which is bigger in area:

Veins or arteries

Arterioles or capillaries

Aorta of vena cava

Veins

Capillaries

Vena cava

32

Effect of turbulent flow on pressure difference

Increase turbulence increases the pressure difference required to create flow (less flow at the same pressure difference as laminar flow)

33

Is flow greater in turbulent or laminar flow overall

Small amount bigger in turbulent

34

How laminar flow relates to vascular resistance

Lamina nearest wall doesnt move, next layer slides under if, velocity highest in center

Larger tubes have higher mean velocity (more things are further away from the wall)

35

How to calculate reynolds number

=
p density x d diameter x v velocity
__________________
N viscosity

36

In a bigger tube more likely it will be turbulent if ___ increasing. Higher ___ means less likely to be turbulent

Velocity
Viscosity

37

___ molecules are more likely to be turbulent

Bigger

38

Reynolds what= laminar flow, what = turbulent

<2000

>2000

39

How driving pressure changes with low compliance

Need twice as much pressure, harder to fill when vessel doesn't push away and make room

40

How to calculate compliance

Change in volume divided by change in pressure

41

What is elastance

How is compliance different

How hard something recoils after stretching

Compliance is how hard it is to inflate something

42

What wall of aorta does in systole and diastole

Systole distends

Diastole recoils

43

Do you want a fast or slow pulse wave and why

Want a slow one, means arteries are more compliant and dont shove all of blood in at once which is what non compliant vessels do

44

Vein and artery compliance comparison

Veins more compliant at low pressures, but at high pressures they are similar

45

What increasing pressure in smooth muscle does to compliance in vessel

Decreases it

46

How volume, pressure, compliance changes with age

Cant push same amount of volume with age, CO decreases because no place for left ventricle to put the blood. Higher pressure and less compliance

47

What happens to compliance as pressures increase

Flattens out, less compliant

48

How compliance affects pulse pressure

Higher compliance means lower pulse pressure

49

How heart rate affects pulse pressure

Peripheral resistance increases with what

Lower hr- higher pulse pressure, diastolic time longer

Higher hr- lower pulse pressure, more output.

Mean pressure increase

50

Tension in wall depends on what

Diameter. Bigger diameter means more tension, smaller means more flaccid

51

Tension = what

Pressure times radius

52

Transmural pressure is what

Pressure inside minus pressure outside

53

Wall thickness ___ with increasing radius

Decreases

54

What happens to wall in aneurysm

High bp leads to them which leads to bigger radius, wall thinner where stretched with greater tension

55

Why small vessels can handle thin wall

Radius small, tension low, pressure low

56

What is flicks law of diffusion

D (diffusion constant)
Times A (area of diffusion)
Times delta P (pressure difference between two sides)
Divided by
D (distance over which area occurs)