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Flashcards in Hemodynamics Ballam Deck (72):
1

the rate at which blood is pumped from the ventricles is called the

cardiac output

2

cardiac output =

SV X HR

3

CO%: Cerebral

15%

4

CO%: Coronary

5%

5

CO%: Renal

25%

6

CO%: Gastrointestinal

25%

7

CO%: Skeletal muscle

25%

8

CO%: skin

5%

9

Three main mechanisms of distributing blood to the major organ systems: 1

CO is constant, but blood flow is redistributed among the organ systems by the selective alteration of arteriolar resistance

10

Three main mechanisms of distributing blood to the major organ systems: 2

CO increases or decreases, but %'s remain the same

11

Three main mechanisms of distributing blood to the major organ systems: 3

CO is altered AND %s are altered

12

Stressed Volume

the volume of blood in the arteries (under high pressure)

13

where is the site of highest resistance to blood flow

arterioles

14

arterioles have what kinds of receptors that do what

alpha 1 adrenergic receptors that cause vasoconstriction. vasoconstriction increases resistance

beta adrenergic receptors

15

at any given moment the greatest amount of blood is contained in the

veins

16

unstressed volume

% of blood in the veins (!00%)

17

veins have ____ receptors

adrenergic receptors, causing contraction and reducing their capacitance, therefore, reducing unstressed volume

18

velocity of blood flow =

v = Q/ A

Q = flow ml/s
A = cross sectional area (cm squared)

A = pi(r^squared), r= radius

19

the units of velocity are

cm/s

20

as vessel diameter increases, velocity

decreases, because radius in the calculation for Area is squared, so it continually gets bigger

21

the relationship between pressure, resistance, and flow: formula

Flow (Q) / Delta Pressure/ R

Q = P/R

22

the magnitude of blood flow is directly proportional to

size of pressure difference

Q = P/R

23

Blood flow is _____ proportional to resistance

inversely proportional

Q = P/R

24

TPR

total peripheral resistance

can be measured by substitution Q (flow) with CO, and the pressure difference between vena cava and aorta

25

SVR

systemic vascular resistance (SVR) = TPR

26

Poiseuille equation tells us what

the relationship between resistance, blood vessel diameter and blood viscosity

the Poiseuille equation allows us to determine the resistance of the a blood vessel to blood flow.

27

Poiseuille equation: formula

R = (8 * viscosity of blood * length of blood vessel)/ (radius of blood vessel raised to fourth power * pi)

28

What big picture relationshops of the Poiseuille equation can we talk about without seeing numbers?

direct and indirect relations, and that with each increase in the radius of the blood vessel, the numerator is reduced by fourth power of the radius

when radius increases, resistance decreases

29

Total resistance of the system arranged in series is

equal to the sum of the individual resistances

R+R+R

30

Which factor in total vascular resistance is the most determinant?

arteriolar resistance

31

the greatest decrease in pressure occurs in the

arterioles, because they contribute the most to resistance

32

Parallel resistance

I/R (total) = 1/R + 1/R etc

as you add R's, total R decreases

33

1500 foot level insights about parallel R and in series R

in series R: the total flow through all of the them will be equal, pressure decreases progressively

in parallel R: flow will be cumulative, each contributing a fraction to the overall flow, but the pressure in them all remains the same

34

Mean pressure of the Aorta

100 mmHg

35

Mean pressure of the Large arteries

100, 120 systolic, 80 diastolic

36

Mean pressure of the arterioles

50

37

Mean pressure of the capillaries

20

38

Mean pressure of the vena cava

4

39

Mean pressure of the Right Atrium

0-2

40

Mean pressure of the Pulmonary arteries

15: systolic 15, diastolic 8

41

Mean pressure of the pulmonary capillaries

10

42

Mean pressure of the pulmonary veins

8 mmHg

43

Mean pressure of the left atrium

2-5 mmHg

44

Which vessel has the most area? What is its volume?

capillaries have the most area but very little volume

45

Which vessel has the most volume? what is its area?

Veins have the most volume and the second most area after capillaries

46

Cardiac output = (Ballam's formula)

(arterial pressure - venous pressure)/TPR (total peripheral resistance)

47

Laminar Flow

blood flow in the cardiovascular system is parabolic

blood towards the center is faster than blood near the vessel walls, as a result each successive layer of blood near the centers is a little bit faster

48

Velocity of blood at the vessel wall is __ and the blood at the center is

0
maximal

49

Turbulence

occurs when vessel wall has disturbances. fluid streams do not remain in a parabolic shape and begin to mix

often accompanied by murmurs

50

What is the energy profile of turbulence compared to laminar flow?

requires more energy to pump (in terms of pressure)
often

51

Reynolds number

dimensionless number that predicts whether blood flow will be laminar or turbulent

52

Reynolds number =

(density of blood)(diameter of blood vessel)(velocity of blood flow)/ viscosity of blood

53

2000

if reynold's is above 2000, blood flow will be turb
if reynolds is below 2000, blood flow will be laminar

54

Increasing what 3 factors will increase Reynold's number?

density of the blood
diameter of the blood vessel
velocity of the blood

55

Decrease what factor will increase Reynold's number

viscosity of the blood

56

bruits

heart sounds made when reynold's is turbulent

57

ateriosclerosis

lesions

58

Compliance of bloodvessels

how much the vessel can expand in response to a given chance in lumen hydrostatic pressure

59

compliance =

(change in volume)/(change in pressure)

60

compliance of arteries vs veins

vein > arteries

C = V/P

61

What kind of compensation does an old artery need in order to hold the same volume as a young artery?

it has to have more pressure

62

Diacrotic notch

is a slight dip in aortic pressure below systole when the aortic valve closes. closure produces momentary retrograde movement of blood back toward valve, causing pressure dip.

63


Pulse pressure

the pressure difference between systole and diastole

64

mean arterial pressure =

diastolic pressure + 1/3 Pulse Pressure

65

increasing smooth muscle causes

shift in compliance, moving blood from veins to arterial side and increasing pressure

compliance itself doesnt really change but shifts curve downward

66

lesions of the arteries will cause

decrease in compliance = pressures in the arteries will be increased

67

compliance is determined by the _____ pressure

pulse pressure , which is the difference is between diastole and systole

68

Equation for

Velocity

Resistance

Reynold's number

Blood flow

compliance

v = Q/A

R = (L * viscosity * 8)/(pi r^4) so think R = 1/ r^4

Reynolds = (Density * Velocity * diameter of vessel)/viscosity of blood

Q = deltaP/R

Compliance = V/P

69

effect of aortic stenosis on arterial pressure

causes a decreases in aortic pressure

70

effect of arteriosclerosis on arterial pressure

increases pressure

71

how would an increase in resistance effect the pulse pressure?

it wouldnt change, but the mean pressure would increase

72

Swansgans catheter

put in the jugular vein, goes

vein ---> right atria --> right ventricle ---> pulmonary artery: balloon opens here

tells us pressure in left atrium, left ventricle but actually a little bit greater than left ventricle pressure