vascular Flashcards
(172 cards)
1
Q
the right side of the heart delivers _____ of its blood to the _____
A
100%
lungs
2
Q
the left side of the heart delivers oxygenated blood to other tissues in the body through systemic circulation. list the body parts in order of which recieves most to least;
A
digestive - 21%
kidneys - 20%
skeletal muscle - 15%
brain - 13%
skin - 9%
other - 8%
liver - 6%
bone - 5%
heart muscle - 3%
3
Q
what is pressure a measure of?
A
force/area
4
Q
what are modern units for pressure?
A
PSi (pounds per square inch), kPa (kilopascal), mmHg (milimeters of mercury)
5
Q
what unit of pressure is used for measuring pressures in the cardiovascular system?
A
mmHG
6
Q
what does mmHg represent?
A
the pressure exerted by a X mm column of liquid mercury
7
Q
why drives the flow of blood through the vascular system?
A
pressure gradient established from the aorta to the right atrium
8
Q
why does pressure decrease along the vascular tree?
A
due to conversion of energy into heat from friction
9
Q
the rate of blood flow is ____ proportional to the pressure gradient and _____ proportional to vascular resistance
A
directly proportional
inversly proportional
10
Q
how do you calculate rate of blood flow?
A
F = pressure gradient/resistance
11
Q
what is pressure gradient?
A
the difference in pressure between the beginning and end of a vessel or organ
12
Q
what is the direction of blood flow in terms of pressure?
A
blood flows from an area of high pressure to an area of lower pressure
13
Q
______ provides the motive force to drive blood flow within conduit vessels and organs
A
blood pressure
14
Q
what determines how much blood each organ will recieve?
A
vascular resistance
15
Q
what is resistance?
A
the measure of the hindrance or opposition of blood flow through a vessel
16
Q
how is resistance produced in the cardiac system?
A
by friction between the moving fluid and stationary walls
17
Q
what are the 3 factors that resistance is dependent on?
A
- blood viscosity (n)
- vessel length (L)
- vessel radius (r)
18
Q
a slight change in vessel radius produces a _____ change in blood flow
A
significant
19
Q
what is the equation to which resistance is proportional to?
A
1/r^4
20
Q
what are the assumptions for Poiseuille’s law?
A
- newtonian fluid - viscosity of blood remains constant
- laminar flow - blood travels smoothly without turbulence
- no slip condition - the speed of the blood that is in contact with the vessel wall is 0
- steady flow
- cylindrical vessels
- rigid vessel walls
21
Q
flow is equivalent to what mathamatical equation?
A
r^4
22
Q
flow is equivalent to what?
A
pressure gradient
23
Q
what are arteries?
A
rapid transit ways that carry blood away from heart to tissues
24
Q
what are arterioles?
A
smaller branches of arteries that control distribution of blood
25
what are capillaries?
smaller branches of arterioles optimized for excahnge with surrounding cells
26
what are venules?
after nutrient excahnge, blood goes into the venules for return back to heart
27
what are venules?
form when venules merge, return blood to heart
28
what is the structural features of arteries?
thick, highly elastic walls with a large radi
29
what are the structural features of arterioles?
highly muscular, well innervated walls with small radi
30
what are the structural features of capillaries?
very thin walled
31
what are the structural features of veins?
thin walled compared to arteries, highly distensible, with large radi
32
an artery has the following structure; (inner-outer)
endothelium
basement membrane
elastic fibers
smooth muscle
elastic fibers
connective tissue coat
33
an arteriole has the following structure; (inner-outer)
endothelium
basement membrane
smooth muscle
connective tissue coat
34
a capillary has the following structure; (inner-outer)
endothelium
basement membrane
35
a large vein has the following structure; (inner-outer)
venous valve + endothelium
basement membrane
smooth muscle
conncetive tissue
36
what are conduits?
rapid-transport passageways for blood from heart to organs. due to their large radius, these large arteries offer little resistance to blood flow
37
what is pressure reservoir?
provides driving force for blood when heart is relaxing and refilling
38
compliance of arteries is related to _________
connective tissue components including;
collagen fibers - tensile strength
elastin fibers - elasticity to arterial fibers
39
blood pressure on its own usually refers to the blood pressure within _________
large central arteries of the systemic circulation
40
why does mean BP fall across the systemic vasculature?
in proportion to the resistance it encounters
41
inadequate BP can lead to___
inadequate tissue blood flow
42
excessive BP can cause _______
immediate problems such as overload on the heart or excessive tissue blood flow
43
even modest increases in BP can increase the risk of _______
cardiovascular disease
44
pulse pressure can be determined by what mathamatical equation?
Psystolic - Pdiastolic
45
BP refers to the pressure generated as a consequence of _______
ventricular ejection
46
how do you determine mean arterial pressure?
MAP = diastolic pressure + 1/3 pulse pressure
47
pressure ahead of resistance is also known as?
arterial pressure
48
pressure after resistance is also known as?
venous pressure
49
ohms law determines;
Parterial - Pvenous = CO x TPR (total peripheral vascular resistance)
50
which pressure is normally very small and can be considered neglible in ohms law?
Pvenous
51
a decrease in CO will have what effect of BP?
decrease
52
an increase in TPR will have what effect on BP?
increase
53
an increase in CO and decrease in TPR will have what effect on BP?
stabilized
54
can the normal distribution of blood from the left side of the heart at rest be changed?
yes. it is changed according to metabolic demands of the tissues
55
veins carry deoxygenated blood, arteries carry oxygenated blood... but there is 1 exception to this rule, what is it?
the pulmonary arteries that carry deoxygenated blood from the heart to the lungs
56
what is the tunica adventitia or externa?
the external layer of blood vessel tissues
57
what is the tunica media?
the middle layer of blood vessel tissues
58
what is the tunica intima?
the inner layer of blood vessel tissues
59
all types of blood vessels have a single layer of _______ cells that makw up most of the tunica intima
endothelial cells
60
where is the highest proportion of collagen fibers found?
in large veins
61
what is the windkessel effect?
when the heart contracts it ejects blood into the aorta which will stretch the arteries aas it rapidly flows. this energy will be stored as elastic energy and when the heart finishes contracting there will be elastic recoil.
62
what type of pressure is covered under hydrodynamics?
blood pressure produced by the contraction of the ventricular muscle which drives blood flow through circulation
63
what is hydrostatic pressure?
- pressures of fluid that are somehow confined and not able to move and for which ohms law does not apply
- the pressure resulting from the height of the fluid column
64
what is the equation that is representative of hydrostatic pressure?
P = height of fluid coolumn x fluid density
65
mercury is ________ times denser than water
13.6
66
what type of system was used to make the ffirstt measurement of BP?
a vertical glass column of water
67
why would a coulmn of water have to be taller than a column of mercury to accurately depict the same BP?
beacuse of the difference in density
68
can gravity affect BP?
yes because blood is a clumn of fluid
69
would regions above the heart have increased or decreased arterial pressure?
decreased
70
would regions below the heart have increased or decreased arterial pressure?
increased
71
blood is ______ times denser than water
1.06
72
each meter of elevation of a verticle column of blood corresponds to __________ mmHg
78
73
to minimize the effect of gravity on BP, what is used as a referance point?
the heart (brachial artery)
74
can BP measurements be taken from places other than the brachial artery
yes they would just have to corrected to the pressure expected at the heart level
75
when standing, what effect does gravity have on blood?
promote the pooling of blood in the veins of the lower limbs and impede venous return to the heart
76
what does a sphygmomanometer combine?
a cuff to occlude an artery
something to generate cuff pressure
something to measure cuff pressure
hg column
77
how does a blood pressure cuff work?
- the BP cuff is inflated well above systolic pressure and then slowly deflated
- when it is above systolic pressure the artery is collapsed and no arterial blood flow will occur and a korotkoff sound will not be heard
- when it is below systolic pressure but above diastoli cpressure thge artery is partially collapsed so some aarterial flow will occur and a korotkoff sound will be heard
- when cuff pressure is less that diastolic the aretery will be open and blood flow can occur quietly so korotkoff sounds wont be heard
78
what is the method for noninvasive BP measurement?
korotkoff sounds with a stethoscope
79
inflating the BP cuff causes;
when it is above systolic pressure the artery is collapsed and no arterial blood flow will occur and a korotkoff sound will not be heard
80
as the cuff begins to deflate what happens?
when it is below systolic pressure but above diastoli cpressure thge artery is partially collapsed so some aarterial flow will occur and a korotkoff sound will be heard
81
when the cuff is almost fully deflated what happens?
when cuff pressure is less that diastolic the aretery will be open and blood flow can occur quietly so korotkoff sounds wont be heard
82
when are korotkoff sounds heard?
when the BP cuff is less than systolic pressure but higher than diastolic pressure
83
using the korotkoff method, how do you determin systolic and diastolic BP?
systolic - when korotkoff sound first appears
diastolic - when the last korotkoff sound is heard
84
what are considered as major resistance vessels?
arterioles
85
how does adjusting the radius of arteriooles beneficial?
- help distribute cardiac output ammong systemic organs depending on bod's momentary needs
- help regulate arterial blood pressure
86
what are the methods involvedd in adjusting arteriole resistance?
vasoconstriction and vasodialation
87
what is vasoconstriction?
- descrbes the process of narrowing a vessel
- results from contraction of smooth muscle layer
- leads to increased resistance and decreased flow through that vessel
88
what is vasodialation?
- the enlargement in internal circumference and internal radius if vessel
- results from relaxation of smooth muscle layer
- leads to decreased resistance and increased flow through that vessel
89
vascular smooth muscle cells sustain a level of partial contraction which is referred to as __________
vascular tone
90
what are the 2 factors responsible for vascular tone?
myogenic activity of smooth muscle
sympathetic fibers continually release norepi
91
vasoconstriction can be caused by;
- increased myogenic activity
- increased oxygen
- decreased carbon dioxide
- increased endothelian
- increassed sympathetic stimulation
- vasopression
- angiotensin 2
- cold
92
vasodialation can be caused by;
- decreased myogenic activity
- decreased oxygen
- increased carbon dioxide
- increased nitic oxide
- decreased sympathetic stimulation
- histamine release
- cold
93
if an arteriole changes radius within a certain organ, does that affect other vessels in another\?
yes
94
what are chemical influences on arteriolar radius?
local metabolic change
histamine release
95
what are physical influences on arteriolar radius?
local application of heat or cold
chemical response to shear stress
myogenic response to stretch
96
during exercise, cardiac output changes, what organ/body part would have the highest percent change in flow?
skeletal muscle
97
what are vasoactive mediators?
- decreased oxygen - hypoxia and initiate vasodialation
- increase carbon dioxide - hypercapnia and initiated vasodialation
- increased acid - acidosis and iinitiate vasodialation
- increased potassium - hyperkalemia and initiate vasodialation
- increased osmolarity - initiate vasoconstriction
- adenosine release - initiate vasodialation
- prostaglandi release - different protsglandins will initiate different responses
98
venous pressures are low at the heart level.
true or false
true - approximately 10 mmHg
99
which has higher venous pressure, the foot or the vena cava?
the foot
100
does the cross section of blood vessels maintain its form even in an absence of pressure? why?
yes because the coat of collagen on the outside limits the maximum diameter changes
101
at rest, skeletal muscle recieves about 15% of cardiac out put but goes to _____- during exercise
64%
102
why does the blood supply to the heart and skin increase during exercise?
for increasing the cardiac output and for radiating the heat generated during exercise
103
why does blood supply to the digestive system and kidneys decrease suring exercise?
to send more blood to skeletal muscle
104
what is a decrease in oxygen content referred to as?
hypoxia
105
what is an increase in carbon dioxide content referred to as?
hypercapnia
106
what is an increase in acid referred to as?
acidosis
107
what is an increase in potassium concentration referred to as?
hyperkalemia
108
endothelial cells play an essential role in regulating ________
arteriolar diameter
109
how do endothelial cells regulater arterolar diameter?
- release chemical mediators
- release locally activating chemical messengers in response to chemical changes in the environment
- Endothelian-1 type A causes vasoconstriction in
- endothelian-1 type B causes no release
110
NO is one of the most studied ___-
local vasoactive mediators
111
what are the functions of endothelial cells?
- line the blood vessels and heart chambers like a physical barrier between blood and vessel wall
- secrete vasoactive substances for relaxation or contraction
- secrete substances to stimulate new vessel growth and proliferation of smooth muscle cells
- participate in material exchange between blood and surrounding tissue
- influence formation of platelet plus, clotting, and clot dissolution
- participate in the determination of capillary permeability by contracting to vary the size of the pores between adjacent endothelial cells
112
ACh stimulation of ________ cells causes an influx of _______- into fluo-4 loaded ______- cells which result in flourescence.
the decrease in _________ in the surrounding smooth muscle causes _________
endothelial
Ca2+
endothelial
CA2+
vasodialation
113
what are the functions of NO?
- causes relaxation of arteriolar smooth musclr - control of blood flow through tissues and maintaining mean arterial BP
- dilates the arterioles of the penis and clitoris
- acts as chemical warfare against bacteria and cancer cells via release from macrophages, large phagocyte cells of the immune system
- interferes with platelet function and clotting at vessel damage sites
- serves as a neurotransmitter
- plays a role in the changes underlying memory
- helps regulate peristalsis by promoting relaxation of digestive tract smooth muscle
- helps keep airways open to facilitate movement of air in and out of lungs by relaxing thr smooth muscle cells
- modulates the filtering process involved in urine formation
- directs blood flow to oxygen-starved tissues
- relaxation of skeletal muscle
114
heat leads to ____
vasodialation
it is used in the skin to shed heat from the body core
flushing/reddening
115
cold leads to ____
vasoconstriction
preserves core heat
frost bite
116
people with raynaud's syndrome experience more sensitivity to the cold which in turn leads to greater degrees of ____
vasoconstriction
117
what does shear stress refer to?
the forces exerted on the endothelial cells as blood passes over it
118
increasing sheer stress causes _______
vasodialation - partially through NO
119
in a blood vessel wall, sudden increase in aarterial pressure ___________ the cells and as a result, cell contractions will reduce the radius of the vessels
stretches
120
what is reactive hyperanemia?
an increase in blood flow that occurs after the occlusion of a blood vessel.
the degree of vasodialation is proportionate to the oxygen debt created during the stopped flow
121
what is pressure autoregulation?
- intrinsic mechanisms that maintain a constant level of blood flow over a specific range of pressures
- blood flow is kept constant by mechanisms that adjust the radius in order to alter resistance in response to a change in pressure
122
what is autoregulation critical for?
functions of the kidneys, brain and heart
123
what are the influences of norepi on smooth muscle?
- brain arterioles do not constrict with norepi
- smally coronary vessels do not constrict with norepi
- no parasympathetic innervation to arterioles
124
norepi and epi can influence the ____________- control center in the medulla
cardiovascular
125
sympathetic stimulation of the adrenal medulla influences...
vasopressin and angotensin 2 to maintain body's fluid balance
126
what do vasopressin and angiotensin 2 do?
maintain body's fluid balance
127
vasopressin and angiotensin 2 are potent ___________
vasoconstrictiors
128
receptor alpha1 is located __________ and recieves _________ from sympathetic fibers and adrenal medula and results in the ___________ response
in all arteriolar smooth muscle except the brain
norepi
vasoconstriction
129
receptor beta2 is located ______ and recieves _______ from the adrenal medulla and results in the __________ response
arteriolar smooth muscle in the heart and skeletal muscles
epi
vasodialation
130
capillaries maximize what factor to be the site of exchange between blood and surrounding tissue cells?
surface area
131
there are ________ in capillary walls to passs water soluble substances
pore
132
plasma proteins ___ cross the capillary wall
cannot
133
lipid soluble substances pass through the capillary wall via ____
endothelial cells
134
how are exchangeable proteins moved across the capillary wall?
vesicualr transport
135
to support increased metabolic demands capillaries are _____ to support RBC flux
recruited
136
endothelial cells produce NO using an enzyme called __________
NO synthase
137
there are 3 types of NO synthases, what are they?
endothelial NO synthase (eNOS)
neuronal NO synthase (nNOS)
inducible NO synthase (iNOS)
138
eNOS oxidises what amino acid into NO?
L-arginine
139
the ________ artery has the lowest innervation of sympathetic fibers
gracilis feed artery
140
there are 3 different types of capillaries, what are they?
continuous
fenestrated
sinusoidal
141
what is a continuous capillary?
has very little gaps between adjacent endothelial cells which leads to limited exchange through the pores
142
what is a fenestrated capillary?
the endothelial cells have large pores which facilitae the movement of large molecuels from the vasculature to the extracellular spce
143
what is a sinusoidal capillary?
endothelial cells feature large gaps between cells which requires the movement of even bigger molecules out of the vasculature
- usually liver and lymph node tissue
144
froms most to least, how is the volume of blood is the circulatory system distributed?
- systemic veins
- systemic arteries
- pulmonary vessels
- heart
- systemic capillaries
- systemic arterioles
145
what factors effect venous return?
- driving pressure from cardiac return
- sympathetically induced venous vasoconstriction
- skeletal muscle activity
- effect of venous valves
- respiratory activity
- effect of cardiac suction
146
what are the most common sites of varicose veins?
lower limbs
esophagus
anal canal
147
what happens to varicose veins? (symptom)
affected vein and surrounding tissue become inflamed and painful
148
what causes varicose veins?
leaky venous valves
149
describe inhalation;
- increased abdominal pressure pushes on the inferior vena cava
- the venous valves ensure unidirectional flow towards thorax
- reduced pressure in the thorax creates suction
150
describe exhalation;
- reduced pressure in the abdomin, it is easier for blood to go up the vena cava
- increased pressure in the thorax compresses thoracic vena cava to push blood to the right atrium
151
ISF resembles __________ in composition
plasma
152
80% of ECF is _________
20% of ECF is _________
ISF
plasma
153
the walls of capillaries are ________
highly permeable
154
capillary BP is denoated by?
Pc
155
what does capillary bP refer to?
fluid or hydrostatic pressure exerted on the inside of the capillary walls by blood
- 37 mmHg arteriolar end
- 17 mmHg venular end
156
how is Plasma-colloid osmotic pressure denoted?
(pi)p
157
what is plasma-colloid osmotic pressure?
forces caused by the colloid dispersion of the plasma proteins. protein concentration tends to be higher in the plasma so this force directs fluid into the capillaries
- 25 mmHg
158
how is interstitial fluid hydrostatic pressure denoted?
PiF
159
what is interstitial hydrostatic pressure?
the pressure exerted on the outside of the capillary wall by ISF. tends to push fluid into the capillaries
160
what is interstitial fluid-colloid osmotic pressure deonted by?
(pi)iF
161
what is interstitial fluid-colloid osmotic pressure?
colloid dispersion of plasma proteins inn the ISF, tends to pull fluid out of the capillaries
162
bulk flow of ISF occurs any time there is _________
a net + or - exchange pressure
163
bulk flow is critical is ___________
regulating the distribution of extracellular fluids between plasma and interstitum
- maintains normal balance of plasma and ISF
164
following a hemorrhage, a fall in Pc promotes ________
reabsorption of ISF
165
bulk flow can lead it excess ISF volume in _________
edema
166
what is the lymphatic system?
the network of vessels that start with blind-ends and end with a single connecction to the venous circulation
an accessory route for returning fluid from interstitial to blood
167
what is lymph
interstitial fluid that has entered the lymphatic system
168
how does lymph enter the vessel?
fluid pressure on the outside of the vessel pushes the endothelial cells free edge inward permitting its entrance
169
why cant lymp escape?
fluid pressure on the inside of the vessel forces the overlapping edges together
170
what is edema?
swelling of tissues that occurs when there is too much ISF
171
what are the possible causes of edema?
- reduced concentration of plasma proteins (loss of proteins from urine in kidney disease, reduced synthesis from liver disease, diet, large burn)
- increased capillary wall permeability (histamine release from injury or allergy)
- increased venous pressure (congestive heart failure, pregnancy)
- blockage of lymph vessels (lymph node removal)
172
