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A&P Final Part 1 > Chapter 21 - Blood Vessels and Circulation - Part 1 > Flashcards

Chapter 21 - Blood Vessels and Circulation - Part 1 Flashcards

1
Q

name the 5 classes of blood vessels

A

arteries
arterioles
capillaries
venules
veins

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2
Q

What do arteries do?

A

carry blood away from the heart

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3
Q

what are arterioles?

A

the smallest branches of arteries

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4
Q

from the arterioles, blood moves into…

A

capillaries

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5
Q

what happens at capillaries?

A

diffusion takes place between the blood and interstitial fluid

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6
Q

from the capillaries, blood enters…..

A

venules

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7
Q

venules unite to form larger….

A

veins

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8
Q

what do veins do?

A

return blood to the heart

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9
Q

where does blood leave the heart?

A

at the pulmonary trunk or the aorta

pulmonary trunk– branches off right ventricle
aorta– branches off left ventricle

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10
Q

the walls of arteries and veins have ___ distinct layers

A

3

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11
Q

name the 3 distinct layers in the walls of arteries and veins

A
  1. innermost (adjacent to lumen) = tunica interna
  2. middle layer = tunica media
  3. outermost (adjacent to surrounding tissue) = tunica externa
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12
Q

only in ______, the tunica interna contains an outer thick layer of elastic fibers called the internal elastic membrane

A

arteries

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13
Q

describe the composition of the tunica media layer

A

smooth muscle and elastic fibers
commonly the THICKEST LAYER in a small artery

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14
Q

what is the name of the thin band of elastic fibers that that separates the tunica media and the tunica externa?

A

the external elastic membrane

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15
Q

in VEINS, the tunica externa is ____ than the tunica media

A

thicket

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16
Q

do the walls of arteries and veins allow diffusion?

A

NO - their walls are too thick

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17
Q

How do arteries and veins compensate for the fact that their walls are too thick to perform diffusion?

A

the walls of these large vessels contain small arteries and veins that supply the smooth muscle cells and fibroblasts of the tunica media and tunica externa

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18
Q

what is “vasa vasorum”

A

“vessels of vessels”
the smaller blood vessels found in the walls of arteries and veins to supply the smooth muscle and fibroblasts of the tunica media and tunica externa

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19
Q

name 4 differences between arteries and veins

A

-arteries have thicker walls

-arteries usually keep their cylindrical shape, but veins often collapse

-arteries are more resilient. When stretched, they keep their shape and elongate. When stretched, they snap back

-Veins typically contain VALVES which prevent the backflow of blood into the capillaries

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20
Q

What property of arteries allows them to passively change their diameter in responses to changes in blood pressure?

A

Elasticity

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21
Q

What property of arteries allows them to ACTIVELY change diameter?

A

Contractility

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22
Q

give 2 examples of an artery actively changing its diameter

A

vascoconstriction
vasodilation

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23
Q

vasodilation and vasoconstriction effect: (3)

A
  1. The afterload on the heart
  2. peripheral blood pressure
  3. capillary blood flow
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24
Q

CONTRACTILITY is important in…

A

hemostasis (stopping the flow of blood)

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25
Q

what are 2 types of arteries?

A

elastic arteries and muscular arteries

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26
Q

elastic arteries are also called…

A

conducting arteries

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27
Q

why are elastic arteries also called conducting arteries?

A

because they carry large volumes of blood away from the heart

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28
Q

muscular arteries are also called…

A

distribution arteries

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29
Q

why are muscular arteries also called distribution arteries?

A

because they distribute blood to the body’s skeletal muscles and internal organs

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30
Q

the pulmonary trunk and aorta are ___ arteries

A

elastic (conducting)

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31
Q

muscular arteries have a thick _____ and the tunica media contains ____smooth muscle cells than the tunica media of elastic arteries

A

thick TUNICA MEDIA, MORE

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32
Q

Superficial muscle arteries are important in….

A

as pressure points to reduce blood flow and control severe bleeding

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33
Q

Elastic arteries are important in…

A

the cardiac cycle

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34
Q

the force opposing blood flow is called _____

A

resistancef

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35
Q

arterioles are called ____ vessels

A

resistance

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36
Q

What causes an aneurysm?

A

When local arterial pressure exceeds the capacity of the elastic components of the tunics — causes a bulge in the weakened wall of the artery

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37
Q

Where do the most dangerous aneurysms occur? (2 places)

A

the brain and the aorta

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38
Q

what are the 2 major types of capillaries?

A

continuous capillaries
fenestrated capillaries

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39
Q

capillary walls are composed of…

A

a single layer of cells and a basement membrane

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40
Q

which type of capillaries contain “pores” that penetrate the endothelial lining and allow for rapid exchange of water and solutes between plasma and interstitial fluid

A

fenestrated

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41
Q

most of the regions of the body are supplied by what kind of capillaries?

A

continuous

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42
Q

what is another type of capillary and what type of capillary do they resemble?

A

sinusoidal capillaries
they resemble fenestrated capillaries

43
Q

what is unique about sinusoidal capillaries

A

they commonly have gaps between adjacent endothelial cells and the basement membrane is sometimes absent
this allows for free exchange of water and solutes

44
Q

what cells line the interior surface of blood vessels?

A

endothelial cells

45
Q

do capillaries function as individual units? explain

A

no
capillaries function as part of an interconnected network called a capillary bed (or capillary plexus)

46
Q

the entrance to each capillary is guarded by a….

A

precapillary sphincter

47
Q

when a precapillary sphincter contracts….

A

blood is diverted into other branches of the network

48
Q

what does the term “angiogenesis” mean?

A

the formation of new blood vessels

49
Q

where is angiogenesis most important?

A

in cardiac muscle

50
Q

the cycling of contraction and relaxation of smooth muscles that changes blood flow through capillary beds is called…..

A

vasomotion

51
Q

how is vasomotion controled?

A

controlled LOCALLY by changes in the concentrations of chemicals and dissolved gasses in the interstitial fluid

52
Q

____ collect blood from all tissues and organs and return it to the heart

A

veins

53
Q

why are the walls of veins usually thinner than arteries?

A

because the blood pressure in veins is lower than in arteries

54
Q

veins are classified by their ____

A

size

55
Q

which are generally larger in DIAMETER - veins or arteries?

A

veins

56
Q

venules collect blood from…

A

capillary beds

57
Q

medium-sized veins are comparable in size to ____ arteries

A

musculat

58
Q

which veins contain valves and why?

A

medium-sized veins and venules
the blood pressure is so low in these places that they cannot overcome the force of gravity.

these valves prevent backflow into the capillaries

59
Q

when is the function of the valves of the medium sized veins and venules particularly important?

A

when we’re standing because blood returning from our feet must overcome gravity to ascend to the heart

60
Q

what may cause the valves of the medium sized veins and venules to not work properly?

A

if the walls of the veins near the valves weaken or become stretched and distorted

61
Q

what causes varicose veins?

A

when valves dont work properly, blood pools in the veins and they becomes grossly distended (bloated)

62
Q

besides varicose veins, faulty valves can also cause….

A

hemorrhoids –painful distortion of adjacent tissues

63
Q

at rest, the largest portion of blood is where in the body?

A

in the systemic veins and venules (blood reservoirs)

64
Q

which are more distensible and why?
veins or arteries

A

veins because their walls are thinner with less smooth muscle tissue

65
Q

what does it mean if a vein has “low capacitance”

A

it expands only at high pressures (like a truck tire)

66
Q

the “capacitance” of a blood vessel is the relationship between __ and __

A

the volume of blood it contains and the blood pressure

67
Q

veins have ___ capacitance and are thus called capacitance vessels

A

high

68
Q

if serious hemorrhaging occurs, what responds?

A

the “vasomotor center” of the medulla oblongata

69
Q

what are the 2 major effects of the vasomotor center when severe hemorrhaging occurs?
(stimulates symapthetic nerves that innervate smooth muscle cells in the walls of medium sized veins)

A
  1. VASOCONSTRICTION – keeps the blood volume within the arteries and capillaries at near normal levels despite significant blood loss
  2. the constriction of veins in certain areas to increase blood flow to delicate organs (aka brain) and to active skeletal muscles
70
Q

what is the “venous reserve”

A

the amount of blood that can be shifted from the liver, skin, and lungs to the general circulation

71
Q

Capillary blood flow is determined by the interplay between ____ and _____

A

pressure and resistance

72
Q

flow is directly proportional to the ____

A

pressure

73
Q

what is the pressure “gradient”

A

the difference in pressure from one end of the capillary vessel to the other

74
Q

When necessary, how can cardiovascular control centers raise the venous pressure to help return blood to the heart?

A

through vasoconstriction

75
Q

What are 3 important cardiovascular pressures?

A

-blood pressure
-capillary hydrostatic pressure
-venous pressure

76
Q

the term blood pressure refers to ___ pressure

A

arterial

77
Q

what is capillary hydrostatic pressure?

A

the pressure within capillary walls

78
Q

for circulation to occur, the circulatory pressure must overcome what pressure?

A

the total peripheral resistance (the resistance of the entire cardiovascuar system)

79
Q

the total peripheral resistance includes a combination of 3 factors:

A

-vascular resistance
-blood viscosity
-turbulence

80
Q

the amount of vascular resistance depends on 2 factors:

A

-vessel length
-vessel diameter

81
Q

describe when vessel length and diameter would cause friction

A

high vessel lengths and small diameters

82
Q

most of the peripheral resistance occurs in….

A

arterioles

83
Q

when blood becomes viscous as in cases of anemia, it flows under ___ pressures only

A

high pressures

84
Q

where does turbulence normally occur?

A

in the heart and large arteries such as the aorta

85
Q

Is arterial pressure constant?

A

no

86
Q

when does arterial pressure rise and fall?

A

rises during ventricular systole
falls during ventricular diastole

87
Q

the peak blood pressure measured during ventricular systole is called the…

A

systolic pressure

88
Q

the minimum blood pressure at the end of _____ is the diastolic pressure

A

ventricular diastole

89
Q

the difference between the systolic and diastolic pressures is called the…..

A

pulse pressure

90
Q

what do we use to report a SINGLE blood pressure value?

A

(MAP) —- mean arterial pressure

91
Q

many cases of hypotension result from….

A

overly aggressive treatments for hypertension

92
Q

blood pressure at or below ___ is normal

A

120/80

93
Q

explain the effect that hypertension has on the cardiovascular system

A

hypertension significantly increases the workload on the heart, and the left ventricle gradually enlarges.

more muscle mass=greater demand for oxygen.

also places physical stress on the walls of blood vessels which promotes the development of:
arterioscelerosis, aneurysms, heart attacks, and strokes

94
Q

what is “elastic rebound”

A

the ability of the arterial walls to stretch during peak blood pressure (ventricular systole) and to recoil to their original size when blood pressures fall (ventricular diastole)

95
Q

as blood moves towards the heart, the veins become ____, resistance ____, and the velocity of blood flow _____

A

larger, drops, increases

96
Q

When you stand, the venous blood inferior to the heart must overcome gravity as it travels up the inferior vena cava.
What 2 factors assist the low venous pressures in compelling this blood to the heart?

A
  1. Muscular compression
  2. Respiratory Pump
97
Q

explain the respiratory pump

A

when we inhale and exhale, blood is pulled into the inferior vena cava and right atrium.

98
Q

the respiratory pump becomes more important during….

A

heavy exercise

99
Q

the “osmotic pressure” of a solution represents…

A

the pressure that must be applied to prevent osmotic movement across a membrane

100
Q

the higher the solute concentration of a solution, the ____ the osmotic pressure

A

greater

101
Q

Filtration is a ____ driven movement of fluid and solutes from ___ to ____

A

pressure driven
from capillaries to interstitial fluid

102
Q

Reabsorption is a ____ driven movement of fluid and solutes from ___ into ____

A

pressure driven
from interstitial fluid into capillaries

103
Q

Under normal conditions, the volume of fluid and solutes reabsorbed is….

A

almost as large as the volume filtered

A&P Final Part 1 (9 decks)

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