Blood Vessels and Circulation Flashcards
1
Q
blood vessels conduct blood between the __ and __
A
heart; peripheral tissues
2
Q
arteries carry blood ___ (to/from) the heart and are called ___ vessels
A
away; efferent
3
Q
veins carry blood ___ (to/from) the heart and are called ___ vessels
A
from; afferent
4
Q
capillaries exchange substances between ___ and __
A
blood and tissues
5
Q
what are the two circuits?
A
- pulmonary
2. systemic
6
Q
the pulmonary circuit goes to and from __
A
gas exchange surfaces on the surface of the lungs
7
Q
the systemic circuit goes to and from __
A
the rest of the body
8
Q
the right atrium collects blood from the __ circuit and delivers it to the right ventricle which pumps it into the __ circuit
A
systemic; pulmonary
9
Q
the left atrium receives blood from the __ circuit and the left ventricle pumps blood to the __ circuit
A
pulmonary; systemic
10
Q
what are the 3 layers of arteries and veins?
A
- Tunica intima
- Tunica media
- Tunica externa
11
Q
what is the tunica intimacy made of?
A
endothelial cells with connective tissue and elastic fibres
12
Q
what is the tunica media made of ?
A
concentric sheets of smooth muscle
13
Q
what is the tunica external made of
A
connective tissue
14
Q
what is another name for the tunica external?
A
tunica adventitia
15
Q
what are the 5 general blood vessel classes?
A
- arteries
- arterioles
- capillaries
- venules
- veins
16
Q
what are the 2 types of arteries?
A
- elastic
2. muscular
17
Q
structure, location and function of elastic arteries
A
large, close to heart, recoil and stretch when heart beats
18
Q
size of muscular arteries
A
medium
19
Q
arterioles have a poorly defined __
A
tunica externa
20
Q
size of tunica media in arterioles
A
1-2 smooth muscle cells thick
21
Q
___ are the only blood vessels that allow exchange between blood and interstitial fluid
A
capillaries
22
Q
venues lack a tunica ___ and resemble expanded __
A
media; capillaries
23
Q
structure of tunica media in medium-sized veins
A
thin, smooth muscle cells and collagen fibres
24
Q
structure of tunica external in medium sized veins
A
thick, longitudinal collagen and elastic fibres
25
__ veins contain all 3 layers
large
26
in large veins, the tunica media is surrounded b a thick tunica __
externa
27
examples of large veins include:
superior and inferior venae cavae and tributaries
28
a typical capillary consists of a tube of __ cells with delicate ___
endothelial; basement membrane `
29
a typical capillary lacks which layers?
tunica externa and media
30
a typical capillary is about the same diameter as a __
RBC
31
what are the two major types of capillaries
1. continuous
| 2. fenestrated
32
structure of endothelial lining in continuous capillaries
complete
33
location of continuous capillaries in the body
in all tissues except epithelia and cartilage
34
continuous capillaries allow diffusion of __ (3)
water, small solutes, lipid soluble material s
35
specialized continuous capillaries in the CNS and thymus have endothelial ___
tight junctions
36
role of specialized continuous capillaries with tight junctions
enables restricted and regulated permeability
37
structure of endothelial lining in a fenestrated capillary
contains pores in the lining
38
what is the role of the pores in fenestrated capillaries?
permits rapid exchange of water and larger solutes
39
location of fenestrated capillaries in the body
multiple parts of the brain, glands, GI tract and kidneys
40
structure of sinusoids
like fenestrated capillaries, but flat and misshapen, gaps between endothelia cells and a thin or absent basement membrane
41
sinusoids permit greater __
exchange of water and solute
42
what is a capillary bed?
interconnected network of capillaries
43
a capillary bed contains several connections between __ and __
arterioles; venues
44
T/f a capillary bed may be supplied by more than one artery
true
45
multiple arteries are called
collateral
46
fusion of arteries is an example of arterial __
anastomosis
47
what is anastomosis?
the joining of blood vessels
48
what is the benefit of a capillary bed being supplied by multiple arteries?
continuous delivery of blood even if one artery is blocked or compressed
49
the capillary bed can be bypassed by ___ that directly connects arteriole to venule
arteriovenous anastomosis
50
the arteriovenous anastomosis is regulated by ___ innervation
sympathetic
51
what is a met arteriole or precapillary arteriole?
initial segment of the connection passageway
52
structure of metarteriole
smooth muscle that can change the vessel's diameter and adjust flow rate
53
what is the thoroughfare channel?
most direct passageway through the capillary bed
54
what are precapillary sphincters?
bands of smooth muscle that contract and relax to control flow into the capillary bed
55
what is vasomotion ?
cycles of contraction and relaxation (in precapillary sphincters?)
56
BP in peripheral venues is less than __ % of that in the ascending aorta
10
57
what is the largest artery>
ascending aorta
58
mechanism are needed to maintain flow of blood in veins against __
gravity
59
what are the valves in the veins?
folds in the tunica intima pointing in the direction of blood flow
60
what is the function of valves in the veins
ensure one-way flow of blood to the heart
61
what are 2 mechanisms of maintaining blood flow against gravity?
valves and muscular contraction
62
what can happen if vein valves don't work properly?
blood can pool in veins and cause distention
63
what are two conditions caused by faulty vein valves?
varicose veins and haemorrhoids
64
t/f the total blood volume is distributed unevenly amongst arteries, veins, and capillaries
true
65
systemic venous system contains __ % of the total blood volume
64
66
the system venous system acts as blood __
reservoirs
67
sytemic arteries contain __% of total volume
13
68
what is venoconstriction?
contraction of smooth muscle fibres in veins
69
venoconstriction ___ the diameter of veins and the amount of blood in the venous system
reduces
70
venoconstriction is a method of maintaining blood volume in the ___ system even with significant blood loss
arterial
71
venoconstriction is controlled by the ____ center in the medulla oblongata
vasomotor
72
___ nerves stimulate smooth muscles in medium-sized veins during venoconstriction
sympathetic
73
cardiovascular regulation is accomplished by adjusting both ___ and ___
cardiac output and blood flow regulation within the systemic and pulmonary circuits
74
auto regulation acts __
locally
75
central regulation involves ___ and __ mechanisms
neural and endocrine
76
central regulation makes coordinated adjustments to ___ (4) so that cardiac output is sufficient
heart rate, stroke volume, peripheral resistance and venous pressure
77
what is blood pressure?
pressure in the cardiovascular system as a whole
78
is arterial or venous pressure always much higher?
arterial
79
why is arterial pressure much higher than venous pressure?
because blood has to be pushed a greater distance through smaller vessels
80
flow through blood vessels is influenced by ___
resistance
81
what is the force the opposes movement in blood vessels ?
peripheral resistance
82
the pressure in capillaries is very __
low
83
what is capillary exchange?
diffusion between blood and interstitial fluid
84
blood pressure in veins is maintained by __ and ___
valves & muscle contraction of peripheral veins
85
what is the venous return?
amount of blood arriving at the right atrium each minute
86
on average, the venous return is equal to the ___
cardiac output
87
what is the total peripheral resistance?
resistance of entire cardiovascular system
88
total peripheral resistance relies on what 3 things?
vascular resistance, viscosity and turbulence
89
what is vascular resistance?
opposition to blood flow in vessels
90
what is the largest factor in total peripheral resistance?
vascular resistance
91
vascular resistance primarily results from the ___
friction between blood and the vessel walls
92
the amount of friction in vascular resistance depends on what 2 factors?
vessel length and vessel diameter
93
an increases vessel length does what to the friction/resistance?
increases it
94
the layer of blood ___ (closet, farthest) wrt the vessel wall travels slowest
closest
95
vasomotor center controls peripheral resistance primarily by altering ___
diameters of arterioles
96
what is viscosity?
resistance to flow caused by interactions among molecules and soluble components in a liquid
97
blood is ___x thicker than water
5
98
why is blood thicker than water ?
cells and plasma proteins
99
disorders affecting the ___ or ___ change viscosity and affect peripheral resistance
hematocrit or plasma composition
100
what is turbulence?
fluid flow with eddies and swirls
101
what causes turbulence?
high flow rates, irregular surfaces, and sudden changes in vessel diameter
102
turbulence is responsible for what heart sounds?
3rd and 4th
103
what does increased turbulence do to the resistance and blood flow?
increase and slow
104
arteriole pressure __ during ventricular systole
rises
105
arteriole pressure __ during ventricular diastole
declines
106
what is systolic pressure?
peak arterial pressure during systole
107
what is diastolic pressure?
minmum arteriol pressure during diastole
108
capillary exchange involves a combination of diffusion, osmosis and __
filtration
109
what is capillary hydrostatic pressure ?
blood pressure within capillary beds
110
____ provides the driving force between filtration in capillary exchange
capillary hydostatic pressure
111
capillary hydrastsic pressure pushes __ and __ out of the bloodstream but not __
water; small molecules; large molecules like plasma proteins
112
capillary hydrostatic pressure is at its highest near the __
arteriole
113
as filtration occurs, blood colloid osmotic pressure (BCOP) ___
increases
114
net filtration pressure (NFP) = ___ - ___
CHP -- BCOP
115
net filtration pressure is positive at the beginning of the capillary and therefor ___ is occurring
filtration
116
net filtration pressure is negative at the end of a capillary and therefor ___ is occurring
reabsorption
117
what predominates at the venue end of the capillary?
reabsorption
118
homeostatic mechanisms ensure adequate __
tissue perfusion
119
what is tissue perfusion?
blood flow through tissues
120
what are the two regulatory pathways for homeostatic mechanisms?
auto regulation and central regulation
121
auto regulation occurs at the __ level
local
122
central regulation controls __ and __
neural and endocrine
123
what causes central regulation to be activated?
ineffective auto regulation
124
what type of receptor responds to changes in blood pressure
baroreceptor
125
baroreceptors are located in the walls of __ (3)
carotid sinuses, aortic sinuses, right atrium
126
increased baroreceptor stimulation leads to __ cardiac output and __ vasodilation
decreased; increased
127
T/f endocrine responses provide short and longterm regulation of cardiovascular function
true
128
endocrine responses use the endocrine functions of the __ (3)
heart, kidneys, pituitary gland
129
what is the immediate response to low blood pressure and volume?
release of epinephrine and norepinephrine
130
what hormones are important in the longterm response to low blood pressure ad low blood volume?
antidiuretic hormone, angiotensin 2, erythropoietin, aldosterone
131
high blood volume stretches the heart wall during diastole which triggers release of __
natriuretic peptides
132
what are the 2 types f natriuretic peptides released?
atrial and brain
133
chemoreceptors respond to blood and CSF changes in __ (3)
CO2, O2, pH
134
chemoreceptors are located in __ (3)
carotid bodies, aortic bodies, medulla oblongata
135
t/f trained athletes have bigger hearts and stroke volumes
true
136
mechanisms can cope with blood losses of ~__% of total blood volume
30
137
what are short term responses to blood loss?
carotid and aortic arteries and the symaptaheic nervous system signal vasoconstriction
138
what is shock?
acute cardiovascular crisis marked by low blood pressure and not enough peripheral flow
139
what are the most common causes of shock?
hemorrhaging and heart disease
140
what is circulatory shock?
positive feedback loops beginning when blood loss is greater than 35%
141
what is circulatory collapse?
when arteriolar smooth muscles and precapillary sphincters cannot contract
