Cardio-Physio-Hemodynamics-Mitov Flashcards
(127 cards)
1
Q
Hemodynamics?
A
the physical behavior of blood as a fluid.
2
Q
Hemodynamics examines the interrelationships between: (5 things)
A
flow, pressure gradients,, resistance, velocity, vessel cross-sectional area
3
Q
Units of flow
A
mL/s
4
Q
Pressure?
A
Force per unit area, Blood pressure measured in mmHg
5
Q
Resistance definition and units?
A
Impedance of flow, mmHg/mL/min -pressure rise associated with an incremental rise in flow
6
Q
Formula for flow?
A
Pressure/Resistance which is analogous to Ohm’s law
7
Q
What is the consequence of too high blood flow?
A
A too-high flow can damage blood vessels and tissue
8
Q
What is the consequence of too-low blood flow?
A
flow that’s too low means tissues served by the blood vessel may not receive sufficient oxygen to function.
9
Q
What is the pressure that exerts on the walls of the blood vessels?
A
Blood pressure
10
Q
Where does blood pressure originate?
A
With the contraction of the heart
11
Q
In what 3 ways is blood pressure modified?
A
altering cardiac activity, vasoconstriction, or vasodilation.
12
Q
What are the main 3 factors that affect resistance in blood vessels?
A
vessel length, vessel radius, and blood viscosity
13
Q
What are the main regions of the circulatory system that generate resistance, due the small caliber of their lumen?
A
The arterioles and capillary networks
14
Q
Which vessles in particular are able to rapidly alter resistance by altering their radius through vasodilation or vasoconstriction?
A
arterioles
15
Q
What must be overcome in order to maintain blood flow throughout the body?
A
resistance
16
Q
Which force overcomes resistance to maintain blood flow?
A
Pressure
17
Q
The distribution of blood circulating to the different regions of the body is determined by the output of the and by the contractile state of the resistance vessels (arterioles) of these regions.
A
left ventricle
18
Q
systolic arterial pressure
A
Peak arterial pressure reached during ejection of blood by the heart
19
Q
Diastolic arterial pressure
A
Lowest arterial pressure reached during diastole, while the heart is relaxed and filling (not ejecting blood).
20
Q
Arterial pulse pressure:
A
The difference between systolic and diastolic arterial pressures; dependent on stroke volume (volume ejected by one ventricle during one contraction), resistance, and arterial compliance.
21
Q
Mean arterial pressure (MAP):
A
The average pressure over a complete cardiac cycle of systole and diastole; dependent on peripheral resistance and cardiac output (volume ejected by one ventricle per unit time).
22
Q
What is the dicrotic notch (incisura)?
A
Only with aortic pressure
23
Q
Describe how pressure changes in the cardiovascular system starting in the left atrium?
A
24
Q
arterial pressure is a is a useful concept because it can be used to calculate overall blood flow, and thus delivery of nutrients to the various organs. It is a good indicator of perfusion pressure (ΔP).
A
Mean
25
What is a good indicator of perfusion pressure (ΔP)?
mean arterial pressure (MAP)
26
The difference between SBP and DBP is called?
pulse pressure
27
What are the two major factors that affect the pulse pressure?
(1) the stroke volume output of the heart and (2) the compliance (total distensibility) of the arterial tree.
28
What is the trend of blood pressure with age?
A gradual increase of SBP, MAP, and DBP
29
What are the name of the sounds heard when measuring BP?
Korotkoff sounds
30
Atherosclerosis:
disease of the large and intermediate-sized arteries in which fatty lesions called atheromatous plaques develop on the inside surfaces of the arterial walls.
31
arteriosclerosis:
general term that refers to thickened and stiffened blood vessels of all sizes.
32
Low values of systolic and pulse blood pressure have been classically considered hallmark signs of which pathology?
aortic valve stenosis
33
What is aortic valve stenosis?
narrowing of the aortic valve so that ventricular ejection is impeded.
34
What causes aortic stenosis?
often occurs as a result of calcium deposits on the leaflets of the aortic valve.
35
Impaired ventricular ejection, combined with the normal inflow of blood from the left atrium, results in an **increased/decreased** volume in the left ventricle during diastolic filling.
increased
36
During aortic stenosis, the increased volume in the left ventricle during diastolic filling **can/cannot** overcome the resistance caused by the stenotic aortic valve.
can
and allows for partial recovery of left ventricular cardiac output
37
Left ventricular pressure vs. right ventricular pressure during aortic stenosis?
left ventricular systolic pressures are much higher than aortic systolic pressures
38
What is patent ductus arteriosus?
The ductus arteriosus (a blood vessel that attaches from the aorta to the pulmonary artery during fetal development after birth) does not close as it should.
39
a heart valve disease in which the aortic valve does not close tightly, allowing blood to flow from the aorta (the largest blood vessel) into the left ventricle (a chamber of the heart).
Aortic regurgitation
40
In which pathology does the aortic incinsura dissappear?
aortic regurgitation
41
Abnormalities in MAP can impact blood and alter the function of the heart.
flow, normal
42
What is a sustained increase in diastolic blood pressure, a sustained increase in systolic blood pressure, or both.
Hypertension
43
How do our arteries change as we age?
loss of blood vessel elasticity and decreased compliance of large arteries
44
Where is the primary focus of damage due to hypertension?
on the left ventricle
45
What pathology can lead to cardiac hypertrophy, ischemic heart disease, coronary artery disease, kidney disease, and/or stroke?
hypertension
46
What are some causes of hypertension?
renal artery stenosis, drug use, sleep apnea, and adrenal diseases.
47
n chronic hypertension, diastolic dysfunction or ineffective left ventricular filling resulting in pulmonary congestion pressure can progress to the **right/left** side of the heart.
Right side
48
Right heart failure can then lead to decreased return to the heart, causing increased systemic venous pressures and high hepatic pressures that may impact liver function
venous
49
right heart failure can then lead to decreased venous return to the heart, causing increased systemic venous pressures and high hepatic pressures that may impact function
liver
50
What results from high pulmonary vascular pressures with certain lung diseases?
Right ventricular failure, known as cor pulmonale
51
hypertension can also be caused by left ventricular or valvular dysfunction from systemic hypertension
pulmonary
52
Study this figure
53
Another cause of hypotension may occur during conditions such as due to circulating pathogen infections that lead to massive and overwhelming vasodilation as a result of a system-wide immune cytokine responses, or septic shock
sepsis
54
Sepsis due to circulating pathogen infections that lead to massive and overwhelming **vasodilation/vasoconstriction** as a result of a system-wide immune cytokine responses, or septic shock
vasodilation
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If the cardiovascular system is unable to supply blood to tissues, especially those of the brain and heart, hypoxemia, metabolic failures, and system organ failure (MSOF) can lead to death
multiple
56
life-threatening condition that results when you lose more than 20 percent (one-fifth) of your body's blood or fluid supply. This severe fluid loss makes it impossible for the heart to pump a sufficient amount of blood to your body.
Hypovolemic shock
57
The decrease in blood volume due to hemorrhage produces a **decrease/increase** in venous return to the heart and a **decrease/increase** in right atrial pressure.
Decrease, decrease
58
When hemorrhage occurs, which two components of the vascular system decrease almost immediately?
Cardiac output and arterial pressure.
59
As a result of hemorrhage, almost immediate reduction of cardiac output and aterial pressure decreases, which aspect has no change?
total peripheral resistance (TPR)
60
What causes the total peripheral resistance (TPR) to decrease as a result of hemorrhage?
compensatroy responses in the cardiovascular system
61
What are the 3 compensatory mechanisms as a result of hemorrhage?
1. Baroreceptor reflex
2. Renin-Angiotensin II -Aldosterone
3. Capillaries
62
What represents the changes in pressure in the arterial system over periods of systole (during which the stroke volume is ejected from the left ventricle) and diastole (during which the heart is refilling and blood in the arterial system continues to flow downstream)?
The arterial pressure wave
63
Arterial pressure is affected by which 4 things?
1. Cardiac output
2. stroke volume
3. arterial compliance
4. peripheral resistance
64
What is the formula for the rate of flow (Q)?
65
What does it mean for the smooth muscle in e in the walls of the arterioles is tonically active?
Always contracted
66
Smooth muscle in arteriole walls are extensively innervated by?
sympathetic adrenergic nerve fibers
67
What type of receptors are found on the arterioles of several vascular beds (e.g., skin and splanchnic vasculature)?
α1-Adrenergic receptors
68
What happens when the α1-Adrenergic receptors are activated in vascular smooth muscle?
When activated, these receptors cause contraction, or constriction, of the vascular smooth muscle.
69
How does the constriction of vasculature (decrease of diameter of the arteriole) affected resistance to blood flow?
Increases resistance to blood flow.
70
What is the site of highest resistance to blood flow?
arterioles
71
**All/ not all** capillaries are perfused with blood at all times.
Not all
72
Which type of adrenergic receptors are found in arterioles of skeletal muscle?
β2-adrenergic receptors
73
β2-adrenergic receptors are found in arterioles of skeletal muscle. When activated, these receptors cause **constriction/dilation?**
Dilation
74
How to calculate systemic vascular resistance with mean arterial pressure, central venous pressure, and cardiac output?
SVR (aka TRP) = (MAP-CVP)/CO
Systemic vascular resistance (also know as total peripheral resistance) = (mean arterial pressure - central venous pressure)/cardiac output
75
How is MAP calculated?
MAP is calculated as MAP=DBP+ (SBP-DBP)/3
76
What is the **central point** of pulmonary function?
exchange across the barrier that separates the alveolar air and the pulmonary capillary blood.
77
What drive's the exchange exchange across the barrier that separates the alveolar air and the pulmonary capillary blood?
Diffusion (Fick's Law)
78
Less resistance to stretch = **more/less** compliance
more
(as in vein walls are thinner and more compliant to hold blood)
79
Where does the majority of the blood volume come from during compensatory efforts of the body during hemorrhage?
Systemic veins and venules
80
Which part of the circulatory system has the highest cross-sectional area?
Capillary beds
81
What part of the circulatory system serves as a major blood volume reservoir?
Veins
82
Flow to the brain is **steady/various** and maintained the **same/different** in rest or exercise.
steady; same
83
Which part of the nervous system controls blood flow to the various organs?
ANS
84
Blood flow within each organ changes with body activities, except in the:
Brain
85
What is velocity?
objects speed in a particlar direction
86
What is the velocity of blood flow?
rate of displacement of blood per unit time.
87
How to calculate Area (or cross-sectional area fo a blood vessel or a group of blood vessels):
A = πr2, where r is the radius of a single blood vessel (e.g., aorta) or the total radius of a group of blood vessels (e.g., all of the capillaries)
88
The velocity of flow should be **lowest/highest** in vessels with the largest total cross-sectional area (capillaries) and **lowest/highest** in the vessels with the smallest total cross-sectional area (aorta).
lowest; highest
89
What is the relationship between velocity and cross-sectional area?
Inverse relationship
As cross-sectional area increases, velocity decreases
90
Under normal physiological conditions, flow through vessels is governed by which law?
Poiseuille’s law
91
The the greatest resistance to flow occurs where?
microcirculation, particularly the arterioles
92
According to Poiseuillie's law:
Flow is **directly/inversely** proportional to the longitudinal pressure gradient (inflow pressure minus outflow pressure).
directly prportional
93
According to Poiseuillie's law:
Flow is **directly/inversely** proportional to the fourth power of the radius of the tube?
directly proportional
94
According to Poiseuillie's law:
Flow is **directly/inversely** proportional to the viscosity of the fluid.
inversley proportional
95
According to Poiseuillie's law:
Flow is **directly/inversely** proportional to the length of the tube (vessel)
96
What is the relationship of resistance to length of tube, viscosity, and radius according to :
Resistance is directly proportional to length of tube.
Resistance is directly proportional to viscosity.
Resistance is inversely proportional to the fourth power of the radius.
97
What is the most important factor effect flow through a tube?
The radius of the tube.
98
to blood flow is determined by blood vessel diameter and organization.
Resistance
99
In a series, increasing resistance to blood flow in any one vessel in the series will **increase/decrease** the total resistance to blood flow.
increase
100
The renal and splanchnic circulations have the resistances arranged in **series/parallel**?
series
101
The aorta and most other vascular beds have the resistances arranged in **parallel/series?**
parallel
102
Opening a new exit route will make it easier for blood to exit the aorta, so adding a new resistance actually **decreases/increases** the total resistance of the system in parallel?
decreases
103
What is the reciprocal of resistance?
conductance
104
What is a measure of the blood flow through a vessel for a given pressure difference?
conductance
105
The conductance of a vessel **increases/decreases** in proportion to the fourth power of the diameter?
increases
106
The farther away the blood is from the vessel wall, **faster/slower** the flow?
Faster
107
What occurs if adjacent layers of blood travel at different velocities?
shear
108
What is a severe consequence of shear?
it breaks up aggregates of red blood cells and decreases blood viscosity.
109
Where is shear the highest in a blood vessel?
at the wall, where shear rate is normally highest, red blood cell aggregation and viscosity are lowest.
110
What is laminar or streamline flow through the blood vessel?
flow through vessels occurs in concentric layers that slip over each other, with fastest flow at the center and slowest up against the walls of the vessel.
111
When streamline flow is disrupted, kinetic energy is squandered on chaotic motion, a pattern known as _._
turbulence
112
Major influencers on Reynolds number (laminar or turbulent flow) are which 2 factors?
1. changes in blood viscosity
2. changes in velocity of blood flow
113
Viscosity desribes a liquids resistance to _?_
flow
114
Viscosity and density are the characteristics of a fluid, but there **is/is no** direct relation between viscosity and density
is no
115
High Reynolds number is associated with?
turbulent flow
116
How would a decrease in viscosity affect Reynolds nimber?
A decreased viscosity (e.g. low hematocrit), would increase Reynolds number.
117
Narrowing of blood vessel, which produces an increase in velocity of flow, would have what effect on Reynold's number?
Increase Reynolds number
118
What can happen to RBCs if blood is stationary or barely moving?
, RBCs have time to adhere to each other and form aggregates that resemble stacks of coins (rouleaux).
119
The tendency for erythrocytes to aggregate at low flow rates depends on the concentration of the larger protein molecules in plasma, especially ?
fibrinogen
120
Changes in blood viscosity with flow rate are much **more/less** pronounced when the concentration of fibrinogen is high.
more
121
RBC aggregates break apart as flow velocity i**ncreases/decreases?**
increases
122
What describes how distensible a blood vessel is ?
Capacitance or compliance
123
Which blood vessels are more compliant?
veins, hence more blood is stored in veins than arteries
124
What happens to veins as we age?
125
The energy driving flow during diastole was stored in the elements of the arterial wall by the ventricle during systole.
elastic
So, energy stored in arterial walls during systole drives blood forward during diastole
126
Arteries with more elastic properties dampen the pulse pressure, this effect is called?
Windkessel effect
127
