CH 21 Blood Vessels & Hemodynamics Flashcards

1
Q

How many layers does a blood vessel have

A

3

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2
Q

What are the three layers of a blood vessel

A

Tunica interna, tunica media, tunica externa

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3
Q

Tunica interna

A

innermost layer, adjacent to lumen

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4
Q

Tunica media

A

middle layer, smooth muscle and elastic fibers

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5
Q

Tunica externa

A

outermost layer, adjacent to surrounding tissue

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6
Q

Arteries carry blood away from the BLANK and to the BLANK

A

heart, tissues

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7
Q

Components of elastic arteries

A

1- large thick walled arteries with elastin in all 3 tunis 2- aorta is one 3inactive in vasoconstriction 4-act as pressure reservoirs–expand and recoil as blood ejected from heart= smooth pressure downstream

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8
Q

Largest arterie

A

aorta

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9
Q

Components of muscular arteries

A

1)distal to elastic arteries 2)deliver blood to organs 3)thick tunic media with more smooth muscle 4) active in vasocontriction

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10
Q

What are the smallest arteries

A

arterioles

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11
Q

Arterioles lead to

A

capillary beds

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12
Q

Arterioles control

A

flow into capillary beds via vasodialation and vasoconstriction

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13
Q

Anastomoses

A

the union of the branches of 2 or more arteries supplying the same region of the body

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14
Q

Anastomoses components

A

1)provides an alternate route for blood flow

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15
Q

Arteries that do not form an anastomoses are called

A

end arteries

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16
Q

Necrosis occurs when

A

an artery is blocked and blood cannot get to that particular region of the body

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17
Q

Capillaries are

A

microscopic vessels that usually connect arterioles and venules

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18
Q

capillary walls are composed of

A

a single layer of cells and a basement membrane

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19
Q

Because their walls are so thin, capillaries permit:

A

the exchange of nutrients and wastes between blood and tissue cells

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20
Q

Continous capillaries are formed by

A

endothelial cells

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21
Q

Venules are

A

the small vessels formed by the union of several capillaries

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22
Q

Venules drain blood from BLANK into BLANK

A

capillaries into veins

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23
Q

Veins are formed from the union of several

A

venules

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24
Q

compared to arteries, veins have a thinner BLANK and BLANK and a thicker BLANK

A

tunica interna and media and a thincker externa

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25
Q

Veins have less blank and blank than arteries

A

elastic tissue and smooth muscle

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26
Q

veins contain

A

valves

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27
Q

At rest, the largest portion of the blood is in:

A

systemic veins and venules (blood reservoirs)

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28
Q

Substances cross capillary walls by (3)

A

diffusion, transcytosis and bulk flow

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29
Q

Diffusion

A

(passes through walls easily)substances such as oxygen, carbon dioxide, glucose, amino acids and hormones cross capillary walls via simple diffusion

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30
Q

Transcytosis

A

(endocytosis on one side and exocitosis on another) large, lipid-insoluble molecules (like insulin) cross capillary walls in vesicles via transcytosis

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31
Q

Bulk Flow

A

(goes between cells, how most things are moved such as nutrients and gases) a passive process in which large number of ions, molecules or particles in a fluid move together in the same direction

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32
Q

bulk flow is more important for

A

regulation of the relative volumes of blood and interstitial fluid

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33
Q

Starling’s law of capillaries

A

under normal conditions, the volume of fluid and solutes reabsorbed is almost as large as the volume filtered

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34
Q

Blood flow is

A

the volume of blood that flows through any tissue in a given time period

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35
Q

Total blood flow is

A

cardio output, the volume of blood that circulates through systemic (or pulmonary) blood vessels each minute

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36
Q

Cardio output =

A

heart rate X stroke volume

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37
Q

What generates BP

A

contraction of the ventricles

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38
Q

BP is determined by (3)

A

CO, blood volume and vascular resistance

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39
Q

the higher the BP the greater the

A

blood flow

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40
Q

systolic pressure

A

pressure exerted in aorta during ventricular contraction

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41
Q

average systolic pressure

A

120 mmhg in normal human

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42
Q

diastolic presure

A

lowest level of aortic pressure

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43
Q

pulse pressure

A

difference between systolic and diastolic pressure

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44
Q

throwing of arteries =

A

pulse

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45
Q

Vascular Resistance (R)

A

is the opposition to blood flow due to friction between blood and the walls of blood vessles

46
Q

The higher the R (vascular resistance)

A

the smaller the blood flow

47
Q

R (vascular resistance) depends on (3)

A

1) size of the blood vessel lumen 2) blood viscosity 3)total blood vessel length

48
Q

Blood factors that remain relatively constant (2)

A

1) viscosity 2)blood vessel length

49
Q

blood viscosity

A

the “stickiness” of blood due to formed elements and plasma proteins

50
Q

Increased viscosity =

A

increased resistance

51
Q

Longer blood vessel=

A

greater resistance encountered

52
Q

Greatest influence on resistance

A

blood vessel diameter

53
Q

Venous Return

A

the volume of blood flowing back to the heart through the systemic veins, occues due to the pressure generated by contractions of the heart’s left ventricle

54
Q

Venous return is assisted by

A

valves, respiratory pump and skeletal muscle pump

55
Q

Where is the cardiovascular center located

A

medulla oblongata

56
Q

what is the cardiovascular center

A

the group of neurons that regulate heart rate, contractility and blood vessel diameter

57
Q

Baroreceptors

A

Important pressure-sensitive sensory neurons that monitor stretching of the walls of blood vessels and the atria

58
Q

2 types of blood pressure controls

A

1) short term neural and hormonal controls 2)long-term renal regulation

59
Q

short term neural and hormonal control of BP

A

counteract fluctuations in blood pressure by altering peripheral resistance and CO

60
Q

long-term renal regulation

A

contracts fluctuations in blood pressure by altering blood volume

61
Q

Direct renal mechanism

A

alters blood volume independently of hormones.

62
Q

arterial system

A

heart–>elastic arteries –>muscular arteries –> arterioles–> capillaries —> venous system

63
Q

venous system

A

capillaries–>post capillary venule–>small veins –>large veins–>heart

64
Q

Elastic arteries are known as

A

conducting arteries

65
Q

muscular arteries are known as

A

distributing arteries

66
Q

arterioles are known as

A

resistance vessles

67
Q

capillaries

A

exchange vessels

68
Q

small and large veins are known as

A

capacitance veins

69
Q

largest arteries are known as

A

elastic arteries

70
Q

the aorta is located off the

A

left ventricle

71
Q

second largest arteries are known as

A

muscular arteries

72
Q

the purpose of muscular arteries

A

to deliver blood to the body

73
Q

muscular arteries are _____ in vasoconstriction

A

active

74
Q

elastic arteries are _______ in vasoconstriction

A

inactive

75
Q

elastic arteries act as pressure reservoirs by

A

expanding and recoiling as blood is filled and ejected from the heart

76
Q

elastic arteries are associated with which part of BP

A

ventricular systole

77
Q

muscular arteries work to get blood to

A

the head, upper and lower extremities

78
Q

which are the smallest arteries

A

arterioles

79
Q

the control system for vasomotor control (vasodialation and vasoconstriction)

A

autonomic system response located in the medulla oblogata

80
Q

when there is sufficient oxygen in the arteries, the precapillar sphinters are

A

contracted

81
Q

when there is insufficient oxygen in the arteries precapillaries sphincters are

A

relaxed

82
Q

thoroughfare channel

A

where blood flows when precapillary sphincters are contracted – space between arterioles and venules

83
Q

3 types of capillaries (3)

A

continuous, fenestrated, sinusoid

84
Q

continous capillaries

A

continuous capillary formed by endothelial cells, tight junctions, commonly found in the brain

85
Q

fenestrated capillaries

A

have medium large holes allowing for quicker transfusion of gas and substances, found where we pick up and drop off waste like the liver and kidneys

86
Q

sinusoid capillaries

A

large holes called sinusoids, found in places of a lot of dead RBC transport like the spleen

87
Q

tunica interna is made of

A

endothelium

88
Q

tunica media is made of

A

smooth muscle

89
Q

veins and venules have a _____ due to ______

A

valve - low pressure of blood

90
Q

hydrostatic pressure in capillaries

A

pushes fluid out of capillaries

91
Q

osmotic pressure in capillaries

A

pulls fluid into capillaries

92
Q

there is more pressure inside the ____ than the ______

A

blood vessels than the tissue

93
Q

net filtration occurs at the

A

arteriolar end of a capillary

94
Q

NFP =

A

outward force

95
Q

NFP in net filtration =

A

10mmHg

96
Q

NFP in net reabsorption

A

-8mmhg

97
Q

Net reabsorption occurs at the

A

venous end of a capillary

98
Q

why does pressure slow in net reabsorption

A

due to surface area and coming in contact with arterial walls.

99
Q

vasocontriction does what to resistance

A

increases

100
Q

if resistance is doubled

A

the resistance is 1/16 as much

101
Q

input to cardiovascular center (nerve impulses) come from

A

higher brain centers, proprioreceptors (monitor joint movement) and chemoreceptors (measuring blood acidity)

102
Q

parasympathetic effects of cardiac output

A

vagus nerves (para) cardiac accelerator nerves (symp) vasomotor nerves (symp)

103
Q

direct renal mechanism is mainly responsive to

A

higher BP

104
Q

the renin-angiotensin-aldosterone mechanism kicks in when BP is

A

Low

105
Q

pathway of renin-angiotensin- aldosterone mechanism

A

renin –>angiotensinogen–>angiotensin 1—>angiotensin 2

106
Q

angiotensin converting enzyme comes especially from

A

lungs

107
Q

where does the conversion of angiotensinogen to angiotensin 1 occur

A

in the liver

108
Q

functions of angiotensin II- how it triggers an increase in BP

A

increases blood volume by stimulating aldosterone (vasoconstriction), causing ADH release, triggering hypothalamic thirst center.

109
Q

hormone released by vasodialation

A

atrial nautriuretic peptide - released by heart with high BP

110
Q

hormone released to increase blood volume

A

aldosterone, antidiuretic hormone

111
Q

hormone released to decrease blood volume

A

atrial natriuretic peptide