Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Human Systems and Anatomy > Factors affecting blood flow > Flashcards

Factors affecting blood flow Flashcards

1
Q

how does blood flow vary

A

from one organ to another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what does blood flow between organs depend on

A

the metabolic demands of each organ system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what does blood flow to the lungs align with

A

cardiac output

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

why does blood flow to the lungs align with the cardiac output

A

because all blood must pass through the lungs for oxygenation and removal of carbon dioxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

which organ system requires blood flow similar to cardiac output

A

the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what increases and decreases the blood flow to specific organs

A

metabolic requirements of the tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

why does blood flow to skeletal muscle increase during exercise

A

greater demand for oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

why does blood flow to the GI system increase following a meal

A

there is greater demand for oxygen following ingestion of food

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

why are there interorgan blood flow differences

A

as a result of alterations in vascular resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

how can the mechanisms of blood flow regulation be categorised

A

local and hormonal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

describe local control of blood flow

A

matches blood flow to metabolic requirements of the tissue systems
direct action on the metabolites on arteriolar resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe the neural/hormonal control of blood flow

A

action of sympathetic nervous system on vascular smooth muscle
action of vasoactive substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are some vasoactive substances involved in hormonal control of blood flow

A
  • histamine
  • bradykinin
  • prostoglandins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the specific needs for blood flow

A
  • delivery of oxygen to tissues and nutrients
  • removal of carbon dioxide and hydrogen ions
  • maintenance of ion concentrations in tissues
  • transport of hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the nutrients that blood delivers to tissues

A

glucose
amino acids
fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the mechanisms by which intrinsic control of blood flow can occur

A

autoregulation
reactive hyperemia
active hyperemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

describe autoregulation

A

maintenance of constant blood flow while arterial pressure changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

example of autoregulation

A

if the coronary arterial pressure decreases, there is immediate compensatory vasodilation of coronary arterioles to decrease the coronary vasculature resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

describe active hyperemia

A

blood flow to tissues is proportional to its metabolic activity
increased blood flow when metabolic activity increases
increased arteriolar dilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

when would there be an increase in blood flow due to metabolic activity

A

exercising skeletal muscle tissue which increases oxygen consumption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

describe reactive hyperemia

A

increase in blood flow in response to a prior period of decreased blood flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

example of reactive hyperemia

A

following a period of arterial occlusion, oxygen debt accumulates. the longer the arterial occlusion, the greater the oxygen debt and the greater the increase of blood flow above the pre occlusion levels. this continues occurs the oxygen debt is reversed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what are the factors that determine resistance to blood flow

A

vessel diameter
vessel length
viscosity of blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how does vessel diameter change

A

with vasoconstriction and vasodilation as a result of contraction and relaxation of vascular smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is the vascular smooth muscle

A

the tunica media

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

how does a small change in vessel diameter affect resistance

A

there are large changes as a result of even just small changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

does viscosity of blood ever really change

A

no it usually remains within a narrow range

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the exception to the concept that blood viscosity changes

A

haemocrit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what can happen to the blood vessels to lead to changes in resistance

A

change in their diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what can cause an increase in blood viscosity

A

dehydration and immobility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what can reduce the risk of increases blood viscosity

A

hydration
movement
compression socks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

why does movement decreases changes in normal blood viscosity

A

it encourages venous return

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what can a change in blood viscosity lead to

A

risk of deep vein thrombosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what is vessel resistance directly proportional to (an increase in one will increase the other)

A

length of the vessel and viscosity of the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what is vessel resistance inversely proportional to

A

radius to the fourth power of the vessel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

describe the equation for the relationship between flow, pressure and resistance

A

flow = change in pressure over resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what is poiseuilles equation

A

Q = r^4 times change in pressure over viscosity times length of the vessel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what does poiseuilles equation describe

A

how flow is related to perfusion pressure, radius, length, and viscosity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what does the poiseuilles equation assume

A
  • flow is through a uniform straight pipe
  • flow is non pulsatile
  • flow is laminar
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what does it mean to say that flow is laminar

A

it is smooth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

when can velocity of flow be considered the same across the tube

A

when the flow has negligible resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

what happens to the velocity of flow as viscosity increases

A

it increases to a maximum at the centre of the tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

do veins have a large or small cross sectional area

A

large

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

how are venous valves orientated

A

toward the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

why are venous valves orientated toward the heart

A

to maintain blood flow in one direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

what is venous return to the heart aided by

A

the action of working skeletal muscles intermittently contracting to compress the veins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

what happens to intrathoracic pressure during exercise

A

it becomes more negative because there are more frequent respirations that increase the pressure gradient between abdominal and thoracic veins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

what is in control of the sympathetic activation of venous return

A

noradrenaline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

how does noradrenaline play a role in venous return

A

sympathetic activation which constricts the veins and increases venous return to the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

what is preload

A

venous return to the right ventricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

what happens when there is an increase in preload

A

the heart will have to work harder to pump the blood out and this can be a problem in coronary artery disease and heart failure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what is angina

A

coronary artery disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

what is coronary circulation

A

this is circulation that facilitates the perfusion of the myocardium
maintains high basal rate of oxygen supply to cardiac muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

what is skeletal muscle adapted for

A

meeting the metabolic demands of skeletal muscle during exercise

55
Q

what is the function of cerebral circulation

A

regulation to maintain cerebral perfusion

56
Q

what name is given to the blood vessels that supply the heart

A

coronary arteries

57
Q

how much of resting cardiac output is provided to the heart through coronary circulation

A

5%

58
Q

what is blood supply to the myocardium derived from

A

right and left coronary arteries

59
Q

where do the coronary arteries originate on the heart

A

at the root of the aorta behind the cusps of the aortic valve

60
Q

what supplies the right ventricle and atrium

A

the right coronary arteries

61
Q

what supplies the left ventricle and atrium

A

the left coronary arteries

62
Q

what are the branches of the left coronary artery

A

left circumflex artery
anterior descending artery

63
Q

what does the left circumflex artery supply

A

the left atrium and ventricle

64
Q

what does the anterior descending artery supply

A

the interventricular spetum and a portion of the right and left ventricles

65
Q

which branch of the left coronary arteries descends to the apex

A

the anterior descending artery

66
Q

what do coronary arteries branch into

A

segments dividing into capillary networks that facilitate oxygen diffusion into cardiac myocytes that have a high ATP requirement

67
Q

what are the epicardial veins

A

venules that the blood drains into following coronary circulation

68
Q

what do the epicardial veins collect into

A

coronary sinus

69
Q

what does the coronary sinus do

A

collect the blood from the epicardial veins to empty blood into the right atrium

70
Q

what is another name for the epicardial veins

A

the coronary veins

71
Q

what are thebesian veins

A

vascular channels on the heart that drain deoxygenated blood from the capillary network in the ventricular wall directly into the cardiac chambers

72
Q

what is the coronary blood flow at rest

A

70-80 ml/min/100g

73
Q

when does perfusion of the myocardium from the coronary arteries occur

A

during early diastole

74
Q

do relaxed ventricles compress the arteries

A

no

75
Q

what constricts the blood vessels

A

contraction of the myocardium

76
Q

what proportion of left coronary blood flow occurs during diastole

A

80%

77
Q

what is coronary blood flow during exercise

A

300-400ml/min/100g

78
Q

what can increase the number of arterioles and capillaries

A

exercise training

79
Q

why does ventricular mass increase with exercise training

A

to meet the physiological demands of prolonged exercise training

80
Q

what is meant by athletic heart

A

this is a physiological adaptation of structural and functional remodelling in response to exercise training

81
Q

what is the difference between exercise induced hypertrophy and pathological hypertrophy

A

the cellular mechanisms

82
Q

what are some pathological causes of cardiac hypertrophy

A

valve heart disease
cardiac myopathy

83
Q

how does muscle circulation change during exercises and what is the reason for this

A

it increases to increase oxygen and glucose delivery to match the increase in work

84
Q

how can the relationship between blood flow and exercise intensity be described

A

coupled

85
Q

what is the vascular resistance of skeletal muscle a major influence of

A

total peripheral resistance

86
Q

what regulates blood flow at rest

A

sympathetic innervation

87
Q

what regulates blood flow during exercise

A

local control mechanisms

88
Q

what are the local vasodilators that work to increase blood flow to skeletal muscle during exercise

A

lactact
adenosine
potassium ions

89
Q

what is the muscle capillary density adapted for

A

muscle function

90
Q

what does alpha one adrenoreceptor activation cause

A

vasoconstriction

91
Q

which form of vasoconstriction is the most usual in the body

A

alpha one induced

92
Q

how does vasoconstriction work

A

it decreases resistance to increase blood flow

93
Q

what does beta two adrenoreceptor activation lead to

A

vasodilation

94
Q

how does vasodilation work

A

decreased resistance, increased blood flow

95
Q

which hormone causes vasodilation during stress or exercise

A

adrenaline released from the adrenal gland

96
Q

during exercise, do all capillaries vasodilate

A

no, there is tonic sympathetic vasoconstriction that continues to feed the arteries and proximal resistance vessels, which prevents excessive decrease in the total peripheral resistance

97
Q

what couples blood flow to exercise intensity

A

the metabolic vasodilation

98
Q

what accounts for half of vascular resistance

A

cerebral arteries

99
Q

which arteries enter the cranial cavity to supply the brain

A

the basilar and internal carotid arteries

100
Q

what forms the circle of willis

A

the anastomosation of the basilar and internal carotid arteries once they enter the cranial cavity

101
Q

describe cerebral autoregulation

A
  • cerebral resistance vessels dilate to maintain perfusion when arterial blood pressure falls.
  • the cerebral blood flow will steeply decline at a blood pressure lower than 60mmHg
102
Q

what happens if the there is hypotension to the brain

A

mental confusion and syncope

103
Q

what is syncope

A

loss of consciousness

104
Q

what are the cerebral resistance vessels sensitive to

A

local hypoxia and arterial carbon dioxide

105
Q

what is hypercapnia

A

too much carbon dioxide

106
Q

what does hypercapnia cause

A

cerebral vasodilation, which is mediated by endothelial nitric oxide

107
Q

what does hypocapnia cause

A

cerebral vasoconstriction, leading to hyperventiculation, reducing cerebral perfusion

108
Q

what is the symptom of cerebral perfusion

A

dizziness

109
Q

what does local hypoxia lead to

A

cerebral vasodilation

110
Q

what does systemic hypoxia stimulate

A

ventilation

111
Q

what are some circulations in the body with specialised local control

A
  • pulmonary circulation
  • skin circulation
  • renal circulation
112
Q

describe the arrangements of blood components in a capillary following centrifugation

A
  • red blood cells are at the bottom
  • buffy coat containing leukocytes
  • plasma at the top
113
Q

what does local control of blood flow allow

A

matching of flow to metabolic demands

114
Q

what does autoregulation allow

A

maintenance to constant blood flow to tissue systems despite changes in arterial pressure

115
Q

why does reactive hyperaemia occur

A

due to occlusion of the vessel lumen which leads to greater blood flow due to accumulation of blood

116
Q

what can cause occlusion of the blood vessel lumen

A

atherosclerotic plaque

117
Q

why is blood flow not smooth

A

there are different factors that can make blood flow turbulent

118
Q

where in the blood vessels is blood flow fastest and why

A

in the centre as there is resistance against the blood flow in the vessel wall

119
Q

describe the importance of venous valves

A

there is no pulsatile pushing or compliance to push the blood flow, so there can be tendency of blood to backflow if there were not these valves to maintain the blood flow in the one direction

120
Q

what aids preload

A

skeletal muscle contraction

121
Q

what constricts the veins to help push blood back toward the heart

A

sympathetic activation

122
Q

what is starlings mechanism

A

greater preload stretches the myocardial cells leading to increased contractility

123
Q

how do coronary arteries profuse cardiomyocytes

A

they branch to become arterioles and capillaries

124
Q

how many mils of blood per minute are involved in coronary circulation

A

70-80

125
Q

what is angiogenesis

A

formation of new capillaries from existing blood vessels

126
Q

what is an angioplasty

A

a procedure used to widen the coronary arteries that are blocked or narrowed

127
Q

what is an angiogram

A

an x ray photograph of blood or lymph vessels to check for blockages to reduce risk of infarction

128
Q

can the myocardium be profused during systole

A

no

129
Q

why is capillary density adapted to muscle function

A

to increase or decrease the metabolic demands of the muscle groups engaged in activity

130
Q

what does tonic vasoconstriction mean

A

it is a slow and graded physiological response

131
Q

what is the specialised circulation of skin related to

A

temperature regulation

132
Q

why was the level of haematocrit in the blood samples of the lab lower than the suggested range

A

there is species variation in the haematocrit layers

133
Q

what must be maintained to maintian the profusion of vital systems

A

cardiac output

Human Systems and Anatomy (54 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions