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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
what are 2 types of arteries?
elastic arteries and muscular arteries
26
elastic arteries are also called...
conducting arteries
27
why are elastic arteries also called conducting arteries?
because they carry large volumes of blood away from the heart
28
muscular arteries are also called...
distribution arteries
29
why are muscular arteries also called distribution arteries?
because they distribute blood to the body's skeletal muscles and internal organs
30
the pulmonary trunk and aorta are ___ arteries
elastic (conducting)
31
muscular arteries have a thick _____ and the tunica media contains ____smooth muscle cells than the tunica media of elastic arteries
thick TUNICA MEDIA, MORE
32
Superficial muscle arteries are important in....
as pressure points to reduce blood flow and control severe bleeding
33
Elastic arteries are important in...
the cardiac cycle
34
the force opposing blood flow is called _____
resistancef
35
arterioles are called ____ vessels
resistance
36
What causes an aneurysm?
When local arterial pressure exceeds the capacity of the elastic components of the tunics --- causes a bulge in the weakened wall of the artery
37
Where do the most dangerous aneurysms occur? (2 places)
the brain and the aorta
38
what are the 2 major types of capillaries?
continuous capillaries fenestrated capillaries
39
capillary walls are composed of...
a single layer of cells and a basement membrane
40
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
fenestrated
41
most of the regions of the body are supplied by what kind of capillaries?
continuous
42
what is another type of capillary and what type of capillary do they resemble?
sinusoidal capillaries they resemble fenestrated capillaries
43
what is unique about sinusoidal capillaries
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
what cells line the interior surface of blood vessels?
endothelial cells
45
do capillaries function as individual units? explain
no capillaries function as part of an interconnected network called a capillary bed (or capillary plexus)
46
the entrance to each capillary is guarded by a....
precapillary sphincter
47
when a precapillary sphincter contracts....
blood is diverted into other branches of the network
48
what does the term "angiogenesis" mean?
the formation of new blood vessels
49
where is angiogenesis most important?
in cardiac muscle
50
the cycling of contraction and relaxation of smooth muscles that changes blood flow through capillary beds is called.....
vasomotion
51
how is vasomotion controled?
controlled LOCALLY by changes in the concentrations of chemicals and dissolved gasses in the interstitial fluid
52
____ collect blood from all tissues and organs and return it to the heart
veins
53
why are the walls of veins usually thinner than arteries?
because the blood pressure in veins is lower than in arteries
54
veins are classified by their ____
size
55
which are generally larger in DIAMETER - veins or arteries?
veins
56
venules collect blood from...
capillary beds
57
medium-sized veins are comparable in size to ____ arteries
musculat
58
which veins contain valves and why?
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
when is the function of the valves of the medium sized veins and venules particularly important?
when we're standing because blood returning from our feet must overcome gravity to ascend to the heart
60
what may cause the valves of the medium sized veins and venules to not work properly?
if the walls of the veins near the valves weaken or become stretched and distorted
61
what causes varicose veins?
when valves dont work properly, blood pools in the veins and they becomes grossly distended (bloated)
62
besides varicose veins, faulty valves can also cause....
hemorrhoids --painful distortion of adjacent tissues
63
at rest, the largest portion of blood is where in the body?
in the systemic veins and venules (blood reservoirs)
64
which are more distensible and why? veins or arteries
veins because their walls are thinner with less smooth muscle tissue
65
what does it mean if a vein has "low capacitance"
it expands only at high pressures (like a truck tire)
66
the "capacitance" of a blood vessel is the relationship between __ and __
the volume of blood it contains and the blood pressure
67
veins have ___ capacitance and are thus called capacitance vessels
high
68
if serious hemorrhaging occurs, what responds?
the "vasomotor center" of the medulla oblongata
69
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)
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
what is the "venous reserve"
the amount of blood that can be shifted from the liver, skin, and lungs to the general circulation
71
Capillary blood flow is determined by the interplay between ____ and _____
pressure and resistance
72
flow is directly proportional to the ____
pressure
73
what is the pressure "gradient"
the difference in pressure from one end of the capillary vessel to the other
74
When necessary, how can cardiovascular control centers raise the venous pressure to help return blood to the heart?
through vasoconstriction
75
What are 3 important cardiovascular pressures?
-blood pressure -capillary hydrostatic pressure -venous pressure
76
the term blood pressure refers to ___ pressure
arterial
77
what is capillary hydrostatic pressure?
the pressure within capillary walls
78
for circulation to occur, the circulatory pressure must overcome what pressure?
the total peripheral resistance (the resistance of the entire cardiovascuar system)
79
the total peripheral resistance includes a combination of 3 factors:
-vascular resistance -blood viscosity -turbulence
80
the amount of vascular resistance depends on 2 factors:
-vessel length -vessel diameter
81
describe when vessel length and diameter would cause friction
high vessel lengths and small diameters
82
most of the peripheral resistance occurs in....
arterioles
83
when blood becomes viscous as in cases of anemia, it flows under ___ pressures only
high pressures
84
where does turbulence normally occur?
in the heart and large arteries such as the aorta
85
Is arterial pressure constant?
no
86
when does arterial pressure rise and fall?
rises during ventricular systole falls during ventricular diastole
87
the peak blood pressure measured during ventricular systole is called the...
systolic pressure
88
the minimum blood pressure at the end of _____ is the diastolic pressure
ventricular diastole
89
the difference between the systolic and diastolic pressures is called the.....
pulse pressure
90
what do we use to report a SINGLE blood pressure value?
(MAP) ---- mean arterial pressure
91
many cases of hypotension result from....
overly aggressive treatments for hypertension
92
blood pressure at or below ___ is normal
120/80
93
explain the effect that hypertension has on the cardiovascular system
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
what is "elastic rebound"
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
as blood moves towards the heart, the veins become ____, resistance ____, and the velocity of blood flow _____
larger, drops, increases
96
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?
1. Muscular compression 2. Respiratory Pump
97
explain the respiratory pump
when we inhale and exhale, blood is pulled into the inferior vena cava and right atrium.
98
the respiratory pump becomes more important during....
heavy exercise
99
the "osmotic pressure" of a solution represents...
the pressure that must be applied to prevent osmotic movement across a membrane
100
the higher the solute concentration of a solution, the ____ the osmotic pressure
greater
101
Filtration is a ____ driven movement of fluid and solutes from ___ to ____
pressure driven from capillaries to interstitial fluid
102
Reabsorption is a ____ driven movement of fluid and solutes from ___ into ____
pressure driven from interstitial fluid into capillaries
103
Under normal conditions, the volume of fluid and solutes reabsorbed is....
almost as large as the volume filtered

A&P Final Part 1 (9 decks)

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