Week 2 Flashcards
(95 cards)
1
Q
In order for there to be a change in energy, there must be an ______________ ______________.
A
Energy Gradient
2
Q
Total Energy = ________ + __________
A
Potential energy (PE) + Kinetic energy (KE)
3
Q
What is KE in blood flow?
A
Velocity of Blood
4
Q
What is PE in blood flow?
A
Pressure
5
Q
The main form of energy in the circulatory system is __________________
A
pressure energy (PE)
6
Q
Two forms of circulatory PE are what?
A
- Blood pressure
- Gravitational pressure
7
Q
What is the stroke volume?
A
The amount of blood squeezed into the aorta from the heart
8
Q
What happens when the stroke volume is pumped into the aorta?
A
the pressure is increased in the blood vessels and causes the artery to stretch (distend)
9
Q
Define Systolic pressure
A
the pressure Immediately following a heart beat when the artery is at its fullest distention
10
Q
Define Diastolic pressure
A
the pressure exerted on the artery due to recoil and inertia continuing to pump the blood
11
Q
What is the typical amount of stroke volume?
A
70 mL
12
Q
What is the initial pressure at the heat?
A
120 mmHg
13
Q
Why does blood continue to flow to arterial regions where the pressure is higher than that at the heart?
A
the overall mean pressure decreases in distal arteries
14
Q
Why does blood flow?
A
Because of the PRESSURE GRADIENT from the heart through the circulatory system back to the heart
15
Q
The amount of blood squeezed into the aorta from the heart is called what?
A
Stroke Volume
16
Q
Define “Flow”
A
the volume of a fluid that moves past a certain point in a certain amount time
17
Q
What is the gradient set up in the vascular system allowing blood to flow?
A
the change from high pressure to low pressure
18
Q
Describe how the gradient and flow are related
A
Directly. As the gradient increases, flow increases. As the gradient decreases, flow decreases.
19
Q
What must flow overcome in order to work?
A
Resistance
20
Q
What is Gravitational energy in the vascular system called?
A
Hydrostatic pressure
21
Q
How much does standing increase the pressure at your ankles?
A
by 100 mmHG
22
Q
What causes hydrostatic pressure?
A
Gravity
23
Q
What causes friction in the vascular system?
A
Vessel walls, turbulence at curves & branches
24
Q
Poiseuille’s law tells us what factors are related how?
A
FLOW (Q) = Is directly proportional the the CHANGE IN PRESSURE from point a to point b (delta P) AND inversely proportional to RESISTANCE (R).
25
What factors influence resistance in the resistance equation?
length (friction), viscosity (stickiness), and the radius
26
What factor influences resistance the most?
the radius of the lumen
27
What happens when the arterioles open due to exercise?
resistance decreases and flow increases
28
increased viscosity = ____________
decreased velocity
29
high viscosity = ______________
high hematocrit (# of RBC's/volume)
30
higher thickness of the blood results in ____________
increased resistance (see resistance equation)
31
Do you know the resistance equation and Poiseuille's law?
You don't have to know the details.....just the proportionality's
32
Arterial flow is not a steady continuous stream, rather it moves in a ____________ manner.
Pulsatile
33
Define "Laminar Flow"
Flow happens in various layers with the fastest flow in the middle and each layer to the outside is slower. The slowest flow is by the walls.
34
Why are the edges slower in laminar flow?
Resistance by the vessel walls
35
Flow must be maintained in the body. Therefore in the area of a vessel decreases, the _____________ must increase.
Velocity
36
If a sudden widening happens in a vessel, what happens to the velocity?
it decreases
37
Define "flow separation"
separation of flow layers with reversal of flow direction in a part of the tube
38
T/F. The velocities increase along the inside of a curve.
False. Velocities increase along the outside of a curve.
39
A stenosis or and occlusion can be called a _________
obstruction
40
Define "Stenosis"
a narrowing in an artery typically due to plaque build up in the lumen
41
Define "Occlusion"
completely 100% blocked artery, zero flow
42
What qualifies as a hemodynamically significant stenosis?
A stenosis blocking at least 50% of the artery
43
What happens to BP distal to an obstruction during exercise?
the BP drops significantly due to increased demand
44
Q = ____________ x ___________
Mean velocity x Area
45
Decreased Area results in ___________
Increased velocity
46
Define "Turbulent flow"
chaotic flow with different speeds and directions, occurs at a tight narrowing aka stenosis
47
When an obstruction results in a ________ pressure, the body tries to maintain _______ levels by opening the ___________, thereby ___________ resistance.
lower
flow
arterioles
decreasing
48
The lowest pressure in the body is found at the ________________ where the pressure is _________ mmHG.
Right Atrium
| 2-6
49
If flow remains constant, what happens to the velocity if a blood vessel becomes dilated?
Velocity would decrease
50
Changes in resistance are virtually all due to variations in the _________.
Radius
51
Retrocrade flow occurs due to slight ____________ of distal ____________.
vasoconstriction, arteries
52
A flow stream that has all the same velocities is known as _____________.
Plug flow
53
Arterial ____________ and _____________ are essential properties to all for proper blood flow.
elasticity, capacitance
54
The difference between systolic and diastolic pressures is known as ________________.
Pulse Pressure
55
The ____________ of a stenosis is more important than its _____________.
radius, length
56
What are the three divisions of collateral vessels?
Stem Arteries, Midzone collateral Arteries, Re-entry arteries
57
_____________ pressure increases in lower portions of the body due to the ____________ of the blood column.
Hydrostatic, weight
58
There is an ______________ in the ____________ pressure as the blood moves from the heart to the ankle. The ___________ pressure simultaneously ___________, so there is a ____________ in the mean pressure from the aorta to the ankles causing the blood to flow from high pressure to low pressure.
increase, systolic
diastolic, decreases
decrease
59
Flow increases if the pressure gradient _________ or the Resistance ____________.
increases, decreases
60
Laminar flow is also known as _____________
Parabolic flow
61
Upon exercise, ____________ open, therefore resistance ____________ and flow _____________.
Arterioles, decreases, increases
62
T/F. Post-exercise pressures should be significantly higher than pre-exercise pressures.
False. Decreased peripheral resistance due to arterioles opening keeps post-exercise pressure about the same or slightly elevated.
63
Pre-existing pathways that enlarge in the presence of stenosis or obstruction are know as___________.
Collateral vessels
64
Increased viscosity = __________ velocity
decreased
65
lower resistance = ____________ flow rate
higher
66
Flow separation is present during _________ and absent in ___________.
systole, diastole
67
For any fluid to flow, there must be an energy gradient. Which of the following creates the energy gradient needed in the vascular system for blood flow?
a. Velocity
b. Pressure
c. Radius
d. Resistance
B. Pressure
68
If there is an increase in the kinetic energy in a system, the potential energy must ____________.
a. Stay steady
b. Decrease
c. Increase
d. Unable to determine which direction it will go.
B. Decrease
69
Which of the following contributes the most energy to the vascular system?
a. Velocity
b. Pressure
c. Gravity
B. Pressure
70
Contraction of which section of the heart directly contributes the most energy into the peripheral vascular system?
a. Left atrium
b. Right atrium
c. Left ventricle
d. Right Ventricle
C. Left Ventricle
71
Which of these variables contributes the most resistance to flow?
a. Viscosity of the blood
b. Velocity
c. Length of the vessel
d. Radius of the vessel
D. Radius of the vessels
72
Which of these contributes the most to potential energy in the vascular system?
a. Velocity
b. Pressure
c. Gravity
B. Pressure
73
Fluids move from an area of high pressure to an area of low pressure. Since the systolic pressure increases slightly from the aorta to the ankles, why does blood flow down the leg?
The overall mean pressure decreases in distal Arteries
74
Which vessels demonstrate the greatest drop in pressure as blood moves through it?
a. Large arteries
b. Medium arterias
c. Arterioles and capillaries
d. Veins
C. Arterioles and Capillaries
75
Which of the following is defined as the amount of a fluid flowing past a certain point in a certain amount of time?
a. Pressure gradient
b. Flow
c. Velocity
d. Stroke volume
B. Flow
76
Which of the following conditions will create the most flow?
a. High pressure gradient
b. High resistance
c. Low pressure gradient
d. Low resistance
A. High pressure gradient
77
What is the term that describes potential energy created by gravity?
a. Hydrostatic pressure
b. Hypertension pressure
c. Hypovolemic pressure
d. High amplitude pressure
e. Hypercholesterolemia pressure
A. Hydrostatic pressure
78
Gravitational energy is estimated to add about how much pressure to the ankle arteries and veins when a person is standing?
a. 0mmHg
b. 50mmHg
c. 100mmHg
d. 150mmHg
C. 100 mmHg
79
When a person exercises, the arterioles typically open to allow more flow to the muscles. When this happens which of the following characteristics controlling flow changes?
a. Resistance lowers
b. Pressure gradient increase
c. Gravitational energy dissipates
d. Vessel radius decreases
A. Resistance lowers
80
Match the following:
1. Q = ∆P
R A. Bernoulli Principle
2. TE = KE + PE B. Poiseuille’s Law
3. R = 8 ℓ η
π r 4 C. Resistance Equation
B
A
C
81
Which of the following principles explains why the velocity increases at a stenosis, but the pressure decreases?
a. Q = ∆P
R
b. TE = KE + PE
c. R = 8 ℓ η
π r 4
B
82
Which of the following are units for flow?
a. cm/sec
b. mph
c. ml/min
d. m/sec
c. mL/min
83
Blood flow velocities have what change at the outside of a curve in the artery?
a. Increase
b. Decrease
c. Become turbulent
A. Increase
84
What term describes the narrowing of a blood vessel? ______________________
Stenosis
85
In order for flow (Q) to be maintained at a stenosis what happens to the velocity?
a. Increases
b. Decreases
c. Stays the same
A. Increases
86
What happens to the velocity at a sudden widening of the vessel?
a. Increases
b. Decreases
c. Stays the same
B. Decreases
87
A hemodynamically significant obstruction results in ___________ distal to it. Circle all that are true below.
a. Decrease in pressure
b. Increase in velocity
c. Decrease in flow
d. Increase in resistance
e. Arterioles opening
A, C, E
88
What term describes the disruption in the blood flow layers that occurs at a widening when there is a reversal of flow on one side of the lumen?
Flow Separation
89
A hemodynamically significant obstruction is typically defined as a stenosis greater than ______.
a. 30%
b. 50%
c. 75%
d. 90%
B. 50%
90
Collateral arteries typically develop to carry flow past an occluded artery. These collaterals are just as good as the native normal artery in carrying flow so that individuals have no more symptoms when they walk.
a. True
b. False
B. False
91
During the cardiac cycle, when the heart initially empties of blood, the artery is in which of the following states?
a. Resting
b. Expanded
c. Compressed
d. Reversing flow direction
B. Expanded
92
Flow commonly reverses in diastole in the peripheral arteries. Where in the artery does this reversal occur first?
a. Center stream
b. Between center stream and the artery wall
c. Along the wall
d. Across the artery diameter simultaneously
C. Along the wall
93
Why does flow reverse during diastole in a normal peripheral artery?
Primarily because at rest the arterioles are constricted which causes more resistance to flow at the same time that the heart has stopped pumping so flow reverses a little due to lower pressure proximally.
94
Amount of blood ejected from the heart is termed…
a. Pulse wave velocity
b. Kinetic energy
c. Stroke volume
d. Hydrostatic pressure
C. Stroke Volume
95
How does the body react when there is not enough blood flow to the tissues to meet the need?
The body sends a pain signal to the brain and the brain responds by opening the arterioles to increase the flow.
