B4-098 Cardiovascular Hemodynamics Flashcards
1
Q
the heart provides a constant
A
pressure head
2
Q
the goal of the cardiovascuar system is to maintain
A
mean arterial pressure
allows for perfusion
3
Q
The cardiovascular system consists of two pumps arranged in
A
series
4
Q
the systemic organs are arranged in
A
parallel circuits
allos same blood composition to each organ with independent flow
5
Q
the systemic organs are arranged in
A
parallel circuits
allos same blood composition to each organ with independent flow
6
Q
- high pressure
- left heart to organ systems
A
systemic circulation
7
Q
- low pressure
- includes capillaries to right side of heart
A
pulmonary circulation
8
Q
the pressure gradient amoung all organ systems
A
remains the same
9
Q
differences in blood flow between organs are due to
A
differences in vascular resistance of each organ
10
Q
portal special circulatory systems
3
A
- hepatic portal system
- renal portal system
- hypothalmic-pituitary portal system
11
Q
main factors of hemodynamics
6
A
- blood flow
- resistance
- viscosity
- blood velocity
- blood pressure
- compliance
12
Q
driven by a difference in pressure and opposed by the resistance of the vessels
A
blood flow
13
Q
displacement of fluid per unit time
A
blood flow
14
Q
amount of blood delivered by the heart into circulation
A
cardiac output
15
Q
cardiac output during a single heartbeat
A
stroke volume
16
Q
CO=
A
SV * HR
17
Q
at rest, cardiac output for an individual is about
A
5 L/min
18
Q
cardiac output can be increased by
A
increasing stroke volume or heart rate
19
Q
factors that increase stroke volume
A
- preload: filling of the ventricle
- inotropic state: force of contraction
20
Q
factors that decrease stroke volume
A
afterload: resistance to ejection of blood
blockage
21
Q
factors that alter heart rate
A
- heart’s pacemaker activity
- extrinsic factors
22
Q
measures the sound reflected by RBCs in movement
A
ultrasound
23
Q
measures the change in electromagnetic force exerted by the moving blood in an electrial field
A
electromagnetic
24
Q
involves the use of radioactive microspheres, injected on a vessel and collected downstream
A
reference sample method
measures regional blood flow
25
# Implications of Poiseulle's Law
Flow is [...] proportional to the pressure difference between 2 points
directly
26
# Implications of Poiseulle's Law
Flow is [...] proportional to the fourth power of the vessel radius
inversely
27
# Implications of Poiseulle's Law
Flow is [...] proportional to the viscosity of blood
inversely
28
# Implications of Poiseulle's Law
Flow is [...] proportional to the length of the vessel
inversely
29
if a vessel radius decreases by a factor of 2, resistance increases by a factor of
16
| to the fourth power
30
inversely proportional to vessel radius to the fourth power
resistance
31
changes in the radius of arterioles are the major influences on
TPR
32
blood viscosity is determined by
hematocrit
| erythrocyte concentration
33
two factors that affect resistance
* vascular radius
* blood viscosity
34
* site of greatest vascular resistance
* major component of TPR
arterioles
35
arteriolar dilation or constriction will affect the
TPR
36
expresses degress of slipperiness between layers
viscosity
37
organized in concentric layers of fluid moving down the length of a vessel
laminar flow
38
when flow become disorganized it is called
turbulent flow
39
factors that determine if flow is laminar:
* blood velocity
* blood viscosity
40
critical velocity
when flow changes from laminar to turbulent
41
* measure of velocity and viscosity
* increases when blood reaches critical velocity
reynolds number
42
in anemia, viscosity is
decreased
43
in polycythemia vera, viscosity is
increased
44
turbulent flow in the heart creates
murmurs
45
turbulent flow in the vessels creates
bruits
46
intense turbulence may be detected as mechanical vibrations
thrills
47
refers to the rate of displacement of blood within vessels with respect to time
blood velocity
48
inversely related to the cross sectional area of all vessels of a particular segment of the CV system
blood velocity
49
have lowest velocity to facillitate solute exchange
capillaries
50
3 components of blood pressure
1. driving pressure
2. transmural pressure
3. hydrostatic pressure
51
* difference in pressure between two point along the circulatory system
* generated by the pumping action of the heart
* allows blood to flow
driving pressure
52
* change in pressure inside and outside a vessel along radial axis
* influences vessel diameter and vascular resistance
transmural pressure
53
* the change in pressure that exists between two points of a different height
* depends on gravity
hydrostatic pressure
54
standing causes [...] in the legs, and [...] venous return to the heart
pooling
decreases
55
standing reduces
SV and CO
56
vessel with highest pressure
aorta
57
vessel with lowest pressure
cava vein
atria
58
increases blood flow and pressure downstream
arteriolar dilation
59
decreases blood flow and pressure downstream
arteriolar constriction
60
highest and results from blood ejected when the heart contracts
systolic pressure
61
lowest and occurs when heart relaxes and blood returns to heart via veins
diastolic pressure
62
* difference between systolic and diastolic pressures
* depends on SV and arterial compliance
pulse pressure
63
average arterial pressure over time
MAP
64
very low because compliance allows it to hold large volumes of blood
venous pressure
65
pulsatile during cardiac cycle and dependent on systolic pressure
arterial pressure
66
MAP in large systemic arteries
95 mmHg
67
MAP=
CO x TPR
(HR x SV) x TPR
68
arterial pressure rises when
inflow is greater than outflow
| systole
69
arterial pressure falls when
inflow is less than outflow
| diastole
70
* determines how quickly blood volume in the arterial system increases
* influences peak systolic pressure
ejection rate
71
rise in arterial pressure during ejection is directly proportional to the volume of blood added by the heart to the arterial system
stroke volume
72
determinants of arterial systolic pressure
| 3
* ejection rate
* stroke volume
* arterial compliance
73
vessels with higher compliance maintain
reduced blood pressure
74
determinants of arterial diastolic pressure
* rate of runoff
* runoff time
75
how fast blood flows from the arterial system to the venous system
rate of runoff
76
runoff occuring during diastole
| ventricular filling
runoff time
77
major determinant of runoff time is
heart rate
| length of diastole decreases as heart rate increases
78
ways to measure blood pressure
1. directly with a catheter
2. indirectly with sphygomanometer
79
distensibility of blood vessels
compliance
80
high compliance
veins
81
low compliance
arteries
82
[...] results in decreased arterial compliance, which leads to increased arterial systolic pressure
aging
83
causes reduced arterial compliance, leading to increased blood pressure due to hardening of arteries
arteriosclerosis
84
starling's law
venous return to the right heart will decrease with standing, so:
* reduce end diastolic volume
* decrease stroke volume
* reduce cardiac output
85
* results in increased pressure within peripheral veins without a change in resistance
* increases venous return to the heart
venoconstriction
86
[...] increase in blood volume within the arteries will increase arterial pressure significantly
small
| low compliance
87
[...] increase in blood volume within the arteries will increase arterial pressure significantly
small
| low compliance
88
[...] increases in venous blood produce a small increase in venous pressure
large
| high compliance
89
[...] increases in venous blood produce a small increase in venous pressure
large
| high compliance
90
the majority of blood is within
the systemic veins (60%)
91
main regions that can contribute to blood redistribution following blood loss
veins and venules
92
factors that contribute to venous return
* skeletal muscle pump
* respiratory pump
* venous valves
93
contraction of skeletal muscles compresses veins in the legs, forcing blood toward heart
skeletal muscle pump
94
when skeletal muscles relax [...] prevents the backward flow of blood
venous valves
95
effect of inspiration on **right** ventricle
* increased intrathoracic volume
* decreased intrathoracic pressure
* decreased right atrial pressure
* increased pressure gradient between peripheral veins and right atrium
* increased blood flow to right atrium
* increased EDV of right ventricle
* increasd stroke volume
96
effect of inspiration on **left** ventricle
* increased intrathoracic volume
* decreased intrathoracic pressure
* distension of pulmonary veins
* decreased pressure in pumonary veins
* pooling of blood in pulmonary veins
* decreased blood flow to left atrium
* decreased EDV of left ventricle
* decreased stroke volume
97
expiration decreases
* filling of right ventricle
* right ventricular stroke volume
98
expiration increases
**filling of left heart
left ventricular stroke volume**
99
inspiration [....] pressure in the pulmonary veins
reduces
100
decreases venous return to the left heart
inspiration
101
increases venous return to the left heart
expiration
102
increases right ventricular preload
inspiration
103
increases venous return to the right heart
inspiration
104
decreases venous return to the right heart
expiration
105
decreases SV from right ventricle
expiration
106
decreases pulse pressure in pulmonary arteries
expiration
107
why is blood flow slowest through the capillaries?
the cross sectional area of all capillaries is greater than other vessels
108
flow divided by a cross sectional area =
velocity
109
have the highest total cross sectional area and lowest flow velocity
capillaries
110
pulse pressure is [...] proportional to SV and [...] proportional to arterial compliance
directly; inversely
111
index of ventricular contractility
ejection fraction
112
SV/EDV=
ejection fraction
113
EDV-ESV=
stroke volume
114
systolic blood pressure - diastolic blood pressure =
pulse pressure
115
CO * TPR =
MAP
