Physio 14 Flashcards
(119 cards)
1
Q
Give the function of circulation
A
- to transport nutrients to the body tissues
- to transport waste products away
- to transport hormones from one part of the body to another
- to maintain an appropriate environment in all tissue fluids of the body for optimal survival
2
Q
A body organ which serves as additional functions for circulation.
A
Kidneys
3
Q
Controlled to provide the necessary cardiac output and arterial pressure to cause the needed
A
heart and blood vessels
3
Q
Circulation is divided into:
A
- systemic circulation
- pulmonary circulation
4
Q
Other terms for systemic circulation
A
- Greater circulation
- Peripheral circulation
5
Q
Transport blood under high pressure to the tissues
A
arteries
6
Q
Have strong vascular walls and blood flows at a high velocity
A
arteries
7
Q
The last small branches of the arterial system that act as control conduits through which blood is released into the capillaries
A
Arterioles
8
Q
Have strong muscular walls than can close or relax vessels, capable of vastly altering blood flow in each tissue in response to its needs
A
Arterioles
9
Q
Exchange fluid, nutrients, electrolytes, hormones, and other substances between blood and interstitial fluid
A
Capillaries
10
Q
Present in the capillary pores which allows permeability to water and other small molecular substances
A
Capillary pores
11
Q
Collect blood from the capillaries and gradually coalesce into progressively larger veins
A
Venules
12
Q
function as conduits for transport of blood from the venules back to the heart
A
Veins
13
Q
Act as a controllable reservoir for the extra blood.
A
Veins
14
Q
How many % of the entire blood volume of the body is present in the systemic circulation?
A
84%
15
Q
How many % of the entire blood volume of the body is present in the heart and lungs?
A
16%
16
Q
How many % of the blood volume in the systemic circulation is present in veins?
A
64%
17
Q
How many % of the blood volume in the systemic circulation is present in arteries?
A
13%
18
Q
How many % of the blood volume in the systemic circulation is present in arterioles and capillaries?
A
7%
19
Q
Out of 16% of blood volume present in the pulmonary circulation, how much is present in the heart?
A
7%
20
Q
Out of 16% of blood volume present in the pulmonary circulation, how much is present in the pulmonary vessels?
A
9%
21
Q
How many seconds does the blood remains in the capillaries?
A
1-3 seconds
22
Q
Average pressure of aorta
A
100 mm Hg
23
Q
As blood flows through the systemic circulation, its mean pressure falls progressively to?
A
0 mm Hg
24
Systemic capillaries pressure near the arteriolar end
35 mm Hg
25
Systemic capillaries pressure near the venous end
10 mm Hg
26
Average functional pressure in most vascular beds
17 mm Hg
27
Average pulmonary artery systolic pressure
25 mm Hg
28
Pulmonary artery diagnostic pressure
8 mm Hg
29
Mean pulmonary arterial pressure
16 mm Hg
30
What are the three basic principles of circulatory function?
1. The rate of blood flow to each tissue of the body is almost always precisely controlled in relation to the tissue need.
2. The cardiac output is controlled mainly by the sum of all the local tissue flows.
3. Arterial pressure regulation is generally independent of either local blood flow control or cardiac output control.
31
2 factors that determine the blood flow through the blood vessel
1. pressure gradient
2. vascular resistance
32
It is the pressure difference of the blood between the two ends of the vessel which is the force that pushes the blood through the vessel
Pressure gradient
33
Refers to the impediment to blood flow through the vessel
Vascular resistance
34
The flow through the vessel can be calculated by which law?
Ohm's law
35
The quantity of blood that passes a
given point in the circulation in a given period of time
Blood flow
36
The overall blood flow in the total circulation of an adult person at rest
5000 ml/min
37
Refers to the amount of blood pumped into the aorta by the heart each minute
Cardiac output
38
Mechanical and mechanoelectrical devices inserted in series with a blood vessels applied outside of the vessel to measure flow
Flowmeters
39
One of the most important devices for measuring blood flow without opening the vessel
Electromagnetic Flowmeter
40
Record changes in flow in less than 1/100 of a second allowing accurate recording of pulsatile changes in flow
Electromagnetic Flowmeter
41
Another type of flowmeter that can be applied to the outside of the vessel capable of recording rapid, pulsatile changes in flow
Ultrasonic Doppler Flowmeter
42
2 laminar flow of blood in vessels
1. Laminar flow or streamline flow
2. Turbulent flow
43
Refers to blood flowing at a steady rate through a long, smooth blood vessel that flows in streamlines
Laminar flow or streamline flow
44
Refers to blood flowing in all directions in the blood vessel and continually mixing within the vessel
Turbulent flow
45
Velocity of flow in the center of the vessel is far greater than that towards the outer edges
Parabolic velocity profile
46
Enumerate the causes of parabolic profile
1. fluid molecules touching the wall move slowly because of adherence to the vessel wall
2. next layer of molecules slips over these, the third layer over the second, the fourth layer over the third, and so forth
3. fluid in the middle of the vessel can move rapidly because many layers of slipping molecules exist between the middle of the vessel and the vessel wall
4. each layer toward the center flows progressively more rapidly than the outer layers
47
Refers to the blood flows crosswise in the vessel and along the vessel usually forming whorls in the blood
Turbulent flow
48
Refers to the whorls in the blood formed during turbulent flow
Eddy currents
49
When this is present, blood flows with much greater resistance than the flow is streamlined
Eddy currents
50
It add tremendously to the overall friction of flow in the vessel
Eddies
51
Measurement of blood pressure
millimeters of mercury (mm Hg)
52
It refers to the force exerted by the blood against any unit area of the vessel wall
Blood pressure
53
The impediment to blood flow in a vessel but cannot be measured by any direct means
Resistance
54
Resistance must be calculated from? (2)
1. measurements of blood flow
2. pressure difference between 2 points in the vessel
55
A basic physical unit used to express resistance:
CGS (centimeters, grams, seconds)
56
The rate of blood flow through the entire circulatory system is equal to the rate of blood pumping by the heart, which is equal to?
Cardiac output
57
What is the pressure difference from the systemic arteries to the systemic veins?
100 mm Hg
58
Refers to the resistance of the entire systemic circulation>
Total Peripheral Resistance
59
What is the total peripheral resistance?
100/100 or 1 peripheral resistance unit
60
In the pulmonary system, what is the average of mean pulmonary arterial pressure and left atrial pressure?
1. pulmonary arterial pressure - 16 mm Hg
2. left atrial pressure - 2 mm Hg
61
Give the net pressure difference of pulmonary system with a mean pulmonary arterial pressure of 16 mm Hg and left atrial pressure 2 mm Hg?
14 mm
62
Refers to the measure of the blood flow through a vessel for a given pressure difference.
Conductance
63
How is conductance generally expressed?
1. Millimeters/sec/millimeter of mercury pressure
2. Liters/sec/millimeter of mercury
64
It refers to the exact reciprocal of resistance.
Conductance
65
Give the variables of flow of liquid stated by law of Poiseuille (4)
1. Length of the tube (L)
2. Radius (r)
3. Pressure gradient
4. Viscosity of the fluid
66
It is directly proportional to the fourth power of the radius of the vessel.
Rate of blood flow
67
It plays the greatest role of all factors in determining the rate of blood flow through a vessel.
Diameter of a blood vessel
68
True or False. Arterioles have strong vascular walls allowing the internal diameters to change tremendously often as much as fourfold.
True.
69
True or False. A four-fold increase in vessel diameter can increase the flow as much as 256-fold.
True.
70
The arteries, arterioles, capillaries, venules, and veins are collectively arranged in?
Series
71
It is equal to the sum of resistance of the arteries, arterioles, capillaries, venules, and vein.
Total Peripheral Vascular Resistance
71
The blood vessels branch extensively to form ____ that supply the blood to many organs and tissues of the body.
Parallel circuits
72
Permits each tissue to regulate its own blood flow independently of flow to other tissues.
Parallel arrangement
73
In the systemic circulation, approximately what fraction of the total systemic resistance to blood flow is attributed to arteriolar resistance in the small arterioles?
Two-thirds
74
What is the typical range of internal diameters for arterioles?
4 to 25 micrometers
75
The "fourth power law" highlights the significant role of arterioles in regulating blood flow to tissues through:
(a) Large changes in blood pressure
(b) Small changes in vessel diameter
(c) Alterations in blood viscosity
(d) Variations in heart rate
Small changes in vessel diameter
76
In a series arrangement of blood vessels, what is true about the blood flow through each vessel?
(a) The flow varies depending on the vessel diameter.
(b) The flow is the same through each vessel.
(c) The flow decreases progressively along the series.
(d) The flow increases progressively along the series.
The flow is the same through each vessel.
77
For blood vessels arranged in series, how is the total resistance to blood flow calculated?
(a) It is the reciprocal of the sum of individual resistances.
(b) It is the average of the individual resistances.
(c) It is the sum of the resistances of each vessel.
(d) It is the product of the individual resistances.
It is the sum of the resistances of each vessel.
78
What is the primary advantage of the parallel arrangement of blood vessels in the body?
(a) It ensures equal blood flow to all tissues.
(b) It allows each tissue to regulate its own blood flow independently to a great extent.
(c) It maximizes the total resistance to blood flow.
(d) It simplifies the circulatory pathway.
It allows each tissue to regulate its own blood flow independently to a great extent.
79
What is the term used to describe the ease of blood flow and is the reciprocal of resistance?
Conductance
80
How does the surgical removal of a kidney affect the total vascular conductance of the systemic circulation?
(a) It increases the total vascular conductance.
(b) It decreases the total vascular conductance.
(c) It has no effect on the total vascular conductance.
(d) The effect is unpredictable.
It decreases the total vascular conductance.
81
(T/F) A small change in arteriole diameter can lead to a substantial change in blood flow due to the fourth power law
True
82
(T/F) In a series circuit, the resistance to blood flow is lower than the resistance of any individual vessel.
False
83
(T/F) A parallel arrangement of blood vessels allows for independent regulation of blood flow to different tissues.
True
84
According to the "fourth power law," what is the effect on blood flow of a fourfold increase in a vessel's diameter?
(a) A fourfold increase in flow
(b) A sixteenfold increase in flow
(c) A sixty-fourfold increase in flow
(d) A two hundred fifty-sixfold increase in flow
A two hundred fifty-sixfold increase in flow
85
The sum of the conductance of each parallel pathway
Total conductance
86
Enumerate 6 tissues with circulation arranged in parallel that contributes to the overall conductance of the systemic circulation
Brain, kidney, muscle, GI, skin, coronary
87
An important factor of Poiseuille's equation
Viscosity of the blood
88
T/F. The greater the viscosity, the less the flow in a vessel if all other factors are constant.
True.
89
What makes blood viscous?
Due to large numbers of suspended red cells in the blood, each of which exerts frictional drag against adjacent cells and against the wall of the blood vessel
90
Described as the flow of blood through one vessel to the next, without branching.
Series circuit
91
Total resistance is the sum of individual resistance in the pathway. Which circuit is described?
Series circuit
92
The blood can split into multiple smaller vessels, each supplying a different tissue or organ.
Parallel circuit
93
Total resistance is lower than any single vessel in the parallel circuit because blood can choose the path of least resistance. Which circuit is described?
Parallel circuit
94
Give two importance of parallel arrangement
1. Independent blood flow regulation
2. Efficient oxygen delivery
95
The proportion of the blood that is red blood cells.
Hematocrit
96
Factors that influence hematocrit values variation
1. presence of anemia
2. degree of bodily activity
3. altitude at which the person resides
97
A blood disorder that occurs when there are too many red blood cells.
Polycythemia
98
Other factors that affect blood viscosity
1. plasma protein concentration
2. types of proteins in the plasma
99
In case of polycythemia, blood viscosity can become as great as?
10 times that of water
100
T/F. The viscosity of blood plasma is about 2.5 times that of water.
False. It is 1.5 times that of water.
101
The ability of each tissue to adjust its vascular resistance and to maintain normal blood flow during changes in arterial pressure
Blood flow regulation
102
Changes in blood flow can be caused by strong _____ stimulation which constricts the blood vessels.
sympathetic
103
Enumerate 4 vasoconstrictors that can reduce blood flow
1. Norepinephrine
2. Angiotensin II
3. Vasopressin
4. Endothelin
104
The force exerted outward against the walls of a tube by fluid flowing through it/
Pressure
105
The volume of fluid divided by time.
Flow
106
The change in pressure divided by flow.
Resistance
107
Regulated according to the needs of the tissue when the pressure changes are sustained.
Blood flow
108
The relationship between a given flow rate and resulting pressure.
passive-pressure flow
109
Override most of the effects of vasoconstrictors to provide a blood flow appropriate to the needs of the tissue
Local autoregulatory mechanism
110
In passive vascular beds, an increase in arterial pressure leads to:
a) A decrease in blood flow as predicted by Poiseuille's equation.
b) An increase in blood flow greater than predicted by Poiseuille's equation.
c) No significant change in blood flow.
d) An initial increase followed by a decrease in blood flow.
An increase in blood flow greater than predicted by Poiseuille's equation.
111
The decrease in vascular resistance observed with increased arterial pressure in passive beds is due to:
a) Vasoconstriction of the elastic vessels.
b) Increased viscosity of the blood at higher pressures.
c) Distension of the elastic vessels.
d) Activation of autoregulatory mechanisms.
Distension of the elastic vessels.
112
In passive blood vessels, a decrease in arterial pressure leads to:
a) A decrease in vascular resistance.
b) An increase in blood flow.
c) An increase in vascular resistance as the elastic vessels collapse.
d) No change in vascular resistance.
An increase in vascular resistance as the elastic vessels collapse.
113
The arterial pressure at which blood flow ceases in a passive vascular bed due to complete vessel collapse is called the?
Critical closing pressure.
114
Sympathetic stimulation typically affects the passive pressure-flow relationship by:
a) Dilating the vessels and increasing blood flow.
b) Constricting the vessels and decreasing blood flow.
c) Having no effect on isolated blood vessels.
d) Only affecting vessels exhibiting autoregulation.
Constricting the vessels and decreasing blood flow.
115
Inhibition of sympathetic activity in passive vascular beds can lead to:
a) Vasoconstriction and decreased blood flow.
b) Vasodilation and a twofold or more increase in blood flow.
c) No significant change in vessel diameter or blood flow.
d) An unpredictable change in blood flow depending on the initial pressure.
Vasodilation and a twofold or more increase in blood flow.
116
Very strong sympathetic stimulation can sometimes cause blood flow to decrease to zero for a few seconds despite high arterial pressure due to:
a) Activation of the skeletal muscle pump.
b) Maximal vasodilation.
c) Extreme vasoconstriction.
d) Increased blood viscosity.
Extreme vasoconstriction.
117
Even in tissues with limited acute autoregulation, blood flow is regulated according to tissue needs when arterial pressure changes are:
a) Transient and brief.
b) Rapid and sudden.
c) Sustained.
d) Within a very narrow range.
Sustained.
