Brainscape's Knowledge GenomeTM

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


See full index

cardiovascular lectures > control of circulation > Flashcards

control of circulation Flashcards

1
Q

why do we need control (6)

A
  1. maintain blood flow
  2. maintain arterial pressure
  3. distribute blood flow
  4. auto-regulate / homeostasis
  5. function normally
  6. prevent catastrophe
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

components of circulation (5)

A
  1. anatomy
  2. blood
  3. pressure
  4. volume
  5. flow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what carries blood volume in circulation (6)

A
  1. arteries
  2. arterioles
  3. capillaries
  4. endothelium
  5. lymphatics
  6. veins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are arteries

A

low resistance vessels that maintain blood flow to organs during diastole

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

structure of arteries

A
  1. Contain mainly elastic, collagen &
    smooth muscle
  2. The intima is composed of an inner
    surface lining of endothelial cells & a
    very small amount of collagen
  3. The adventitia shows mainly
    collagenous connective tissue
  4. There are two elastic laminae, one at
    the interface of the intima and media
    and the other on the outer edge of the media
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are arterioles

A

smallest branch of an artery
provide the majority of resistance to blood flow
major role in determining arterial pressure
major role in distributing flow to tissues/organs

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

structure of arterioles

A
  1. may have an obvious media & adventitia
  2. smaller arterioles show only a few medial cells with a poorly defined elastic lamina
  3. a thin adventitia & normal intima also exist
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what does TPR stand for

A

total peripheral resistance

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

what are capillaries

A

smallest blood vessels that connect arterioles to venules
transport blood, nutrients and oxygen to cells in your organs and body systems.

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

structure of capillaries

A
  1. tubes of endothelial cells (one cell thick wall - for rapid diffusion) bound to a basement membrane with co-existing pericytes (cells present at intervals along the walls of capillaries
  2. Pericytes have muscle fibres and may regulate blood flow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

describe blood flow in capillaries

A

it is the slowest
- because of the high total cross-sectional
area
-this allows time for exchange of
gases and nutrients

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

what determines blood flow in capillaries

A
  • arteriolar resistance
  • no. of open pre capillary sphincters
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are veins

A

type of blood vessel that return deoxygenated blood from your organs back to your heart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

structure of veins

A
  1. compliant - because they have a thin layer of smooth muscle. A relatively small pressure must be applied to expand them.
  2. low resistance
  3. generally have collagen and little muscle & elastic with the wall & a single
    internal elastic lamina
  4. Veins contain valves for one way flow to the heart - prevent back flow
  5. Some veins are surrounded by skeletal muscle which contracts to increase vein
    pressure and ensure blood flows back to the heart
  6. Show variable thickness
  7. capacitance vessels - means they are the blood vessels that contain most of the blood and that can readily accommodate changes in the blood volume.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

define lymphatic

A

a vessel, similar to a vein, that conveys lymph in the body.

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

what is the lymphatic system

A

network of tissues, vessels and organs that work together to move a colorless, watery fluid called lymph back into your circulatory system (your bloodstream).

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

functions of lymphatic system (4)

A
  1. Maintains fluid levels in your body
  2. Absorbs fats from the digestive tract
  3. Protects your body against foreign invaders
  4. Transports and removes waste products and abnormal cells from the lymph.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

parts of the lymphatic system

A
  • lymph
  • lymph nodes
  • lymphatic vessels
  • collecting ducts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what helps with uni-directional flow (3)

A
  • smooth muscle in lymphatic vessels
  • skeletal muscle pump
  • respiratory pump
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how to calculate cardiac output (CO)

A

Heart Rate (HR) x Stroke Volume (SR) [typically 5 L/min]

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

how to calculate blood pressure

A

CO x Total Peripheral Resistance (TPR)

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

how to calculate pulse pressure

A

Systolic - Diastolic pressure

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

how to calculate mean arterial pressure (MAP)

A

Diastolic pressure + 1/3 PP

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

what is ohms law

A

Flow = Pressure gradient/Resistance

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

what is poiseuilles equation

A

Flow = radius to the power of 4

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

what 2 things are used to govern flow

A

ohms law and poiseuilles equation

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

what is the frank starling mechanism

A

the ability of the heart to change its force of contraction and therefore stroke volume in response to changes in venous return

(how the heart responds to volume)

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

explain the frank starling mechanism

A
  1. stroke volume increases as end-diastolic volume increases
  2. due to the length-tension relationship of muscle
  3. increase in EDV = increase in stretch = increase in force of contraction
  4. cardiac muscle at rest is not at its optimum length
  5. increase in venous return = increase in EDV = increase in stroke volume = increase in CO
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what can stroke volume change in response to

A
  • increasing preload
  • decreasing afterload
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

how do you explain ventricular pressure and volume relationship

A

using pressure-volume loops

these are graphs, where the pressure inside the left ventricle is on the y axis and the volume of the left ventricle is on the x axis. Each loop represents one cardiac cycle, including both ventricular systole and diastole, or more simply, one heartbeat.

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

what is the goal of control of circulation

A

to maintain mean systemic arterial
pressure (MAP) - the average blood pressure in the arteries during the cardiac cycle

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

what is mean systematic arterial pressure (MAP)

A

the average blood pressure in the arteries during the cardiac cycle

mainly determined by arteries and capillaries

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

how to calculate MAP

A

MAP is equal to the diastolic pressure (DP) plus one-third of the pulse pressure
(systolic pressure (SP) - DP)

MAP = DP + 1/3 (SP-DP)

MAP = CO X TPR

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

define blood pressure

A

the pressure of blood within and against the arteries

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

how is blood pressure measured

A

using 2 numbers - systolic and diastolic

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

what is systolic blood pressure

A

measures the pressure in your arteries when your heart beats.

highest when ventricles contract

(100-150mmHg)

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

what is diastolic blood pressure

A

measures the pressure in your arteries when your heart rests between beats.

lowest when ventricles relax

(60-90mmHg)

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

what is pulse pressure

A

systolic blood pressure - diastolic pressure

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

what instrument is used to measure bp

A

sphygmomanometer, which is more often referred to as a blood pressure cuff.
that cuff uses your brachial artery to measure the pressure in your arteries.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

why do you use the brachial artery to measure blood pressure

A

because its convenient to compress

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

what are korotkoff sounds

A

are generated when a blood pressure cuff changes the flow of blood through the artery. These sounds are heard through either a stethoscope or a doppler that is placed distal to the blood pressure cuff.

they have 5 distinct phases

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

what is phase 1 of blood pressure sounds

A

a sharp tapping

provides systolic pressure reading

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

what is phase 2 of blood pressure sounds

A

A swishing/whooshing sound
the softening of the tapping sounds

as the blood flows through blood vessels as the cuff is deflated

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

what is phase 3 of blood pressure sounds

A

A thump (softer than phase 1).

Intense thumping sounds that are softer than phase 1 as the blood flows through the artery but the cuff pressure is still inflated to occlude flow during diastole

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

what is phase 4 of blood pressure sounds

A

A softer, blowing, muffled sound that fades.

Softer and muffled sounds as the cuff pressure is released.
The change from the thump of phase 3 to the muffled sound of phase 4 is known as the first diastolic reading

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

what is phase 5 of blood pressure sounds

A

silence
when the cuff pressure is released enough to allow normal blood flow
provides 2nd diastolic reading

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

what are the 5 components of blood pressure control

A

autoregulation

local mediators

humoral factors

baroreceptors

central (neural) control

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

what is intrinsic regulation of blood flow

A

when tissues and organs within the body are able to intrinsically regulate their own blood supply in order to meet their metabolic and functional needs

they regulate through specific target tissues

some mechanisms originate from within blood vessels (e.g., myogenic and endothelial factors), whereas others originate from the surrounding tissue. The tissue mechanisms are linked to tissue metabolism or other biochemical pathways

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

examples of intrinsic/local regulation of blood flow (3)

A

(myogenic) autoregulation
active hyperemia
reactive hyperemia
local mediators

50
Q

what is extrinsic regulation of blood flow

A

regulates blood flow throughout the body

refers to control by the autonomic nervous system and endocrine system.

51
Q

examples of extrinsic regulation of blood flow

A
  • humoral factors
  • baroreceptors
  • neural control
52
Q

examples of vasoconstricting extrinsic hormonal factors

A

adrenaline (alpha adrenergic receptors)

angiotensin II

Vasopressin (ADH)

53
Q

examples of vasodilating extrinsic hormonal factors

A

AN

adrenaline (beta2 adrenergic receptors)

54
Q

what is myogenic autoregulation

A

an arteriole regulates its own blood pressure based on how much it is stretched

1.increased blood flow
2.stretches vascular smooth muscle
3. muscle automatically constricts
4. until the diameter is normalised
or slightly reduced.

Furthermore when the smooth muscle isn’t getting stretched as much due to low blood pressure, the muscle relaxes and dilates in response.

55
Q

define autoregulation of blood flow

A

the intrinsic ability of an organ to maintain a constant blood flow despite changes in perfusion pressure

Different organs display varying degrees of autoregulatory behaviour.

56
Q

which organs show excellent autoregulation

A

renal
cerebral
coronary

57
Q

which organs show moderate autoregulation

A

skeletal muscle
splanchnic

58
Q

which organs show poor autoregulation

A

cutaneous circulation

59
Q

which organs show poor autoregulation

A

cutaneous circulation

60
Q

how are the brain and heart blood flow controlled

A

intrinsic control

to maintain blood flow to vital organs

61
Q

how is skin blood flow controlled

A

extrinsic control

regulated by sympathetic vasodilation and vasoconstriction mechanisms
via hypothalamus

62
Q

how is blood flow in skeletal muscle controlled

A

both intrinsic and extrinsic

at rest - extrinsic - vasoconstrictor tone is dominant

when exercising - intrinsic mechanisms predominate

63
Q

define intrinsic autoregulation

A

when the arterioles either vasoconstrict or vasodilate in response to changes in resistance seemingly automatically - with the aim of maintaining constant blood flow

64
Q

what are local humoral factors

A

factors that are transported by the circulatory system, that is, in blood

can be vasodilators or vasoconstrictors

65
Q

what are local vasoconstrictor humoral factors

A

endothelin - 1

internal blood pressure (myogenic contraction)

66
Q

what are local vasodilator humoral factors

A

hypoxia - only in systemic circulation

adenosine

bradykinin

NO

K+, CO2, H+

67
Q

structure of endothelium

A

a single layer of spindle/pavement cells with tight adhesions between adjacent cells

little cytoplasm and intra-cellular organelles - but gap/adherence junctions are prominent

can be fenestrated

In some areas they may be very thin (lung) to enable rapid fluid & gas transfer

68
Q

function of endothelium

A

releases substances that aid in blood flow so blood mvoes around body smoothly

69
Q

what does it mean if the endothelium is fenestrated

A

have pores in them for rapid diffusion

found in the liver, kidney
glomeruli & endocrine tissues

70
Q

define blood flow

A

the volume of blood that flows through the systemic circulation per unit of tim

71
Q

units of blood flow

A

volume / time

72
Q

define haemodynamics

A

the physics of blood movements

73
Q

what does the movement of blood depend on

A
  1. pressure
  2. blood flow
  3. resistance
74
Q

how to calculate change in pressure

A

change in pressure = Q x TPR

75
Q

what does Q stand for

A

blood flow (l/min)

76
Q

what does TPR stand for

A

total peripheral resistance

(interchangeable with Systemic Vascular Resistance (SVR)

77
Q

how to calculate the velocity of blood flow

A

velocity = blood flow / area of a vessel (Pi r squared)

78
Q

what are the 2 types of blood flow

A

laminar

turbulent

79
Q

what is laminar blood flow

A

smooth, streamlined flow

80
Q

what is turbulent blood flow

A
  • disruption to laminar flow (e.g. decrease in vessel diameter)
  • “bumps in the road”
  • produces Korotkoff sounds
81
Q

what is resistance

A

physical/mechanical pushback of blood

82
Q

which factors affect resistance (3)

A
  • viscosity
  • vessel length
  • vessel radius - main one
83
Q

define hyperemia

A

increase in blood flow

84
Q

define active hyperemia

A

increase in blood flow when metabolic activity is increased

85
Q

define reactive hyperemia

A

when an organ or tissue has had its blood supply completely occluded a profound transient increase in its blood flow occurs IF blood flow is
reestablish - extreme form of autoregulation

86
Q

define reactive hyperemia

A

when an organ or tissue has had its blood supply completely occluded a profound transient increase in its blood flow occurs IF blood flow is
reestablish - extreme form of autoregulation

87
Q

how many heart sounds are there

A

3

88
Q

describe first heart sound

A

low pitched lub
associated with the closure of the atrioventricular
valves

89
Q

what causes first heart sound

A

associated with the closure of the atrioventricular
valves

90
Q

describe second heart sound

A

a louder dub

91
Q

what causes second heart sound

A

associated with the closure of the aortic & pulmonary valves

92
Q

describe third heart sound

A

low-frequency, brief vibration

93
Q

what causes third heart sound

A

sounds of blood rushing into the left ventricle

94
Q

what is the medullary cardiovascular centre

A

located in the medulla

contains pressor region and depressor region

95
Q

how does the pressor region increase blood pressure

A

by increasing
- vasoconstriction
- cardiac output (by increasing stroke volume and heart rate)
- contractility

96
Q

what does the pressor region do

A

increases blood pressure

97
Q

is the pressor region sympathetic or parasympathetic

A

sympathetic

98
Q

what does the depressor region do

A

decreases blood pressure

99
Q

how does the pressor region decrease blood pressure

A

by inhibiting the pressor region

100
Q

is the depressor region sympathetic or parasympathetic

A

parasympathetic

101
Q

route of the pressor region

A
  • Pressor region > sympathetic route > medulla > spinal cord > synapses at T1-L2 > Heart
102
Q

route of the depressor region

A

Depressor region > medulla > vagus nerve > heart

103
Q

what do central chemoreceptors in the medulla do

A

respond mainly to a decrease in pH (due to CO2 diffusing across the blood-brain barrier thereby reducing the pH of the CSF

104
Q

what are baroreceptors

A

a type of mechanoreceptor allowing for the relay of information derived from blood pressure within the autonomic nervous system

105
Q

2 types of baroreceptors

A
  1. high-pressure arterial baroreceptors
  2. low-pressure volume receptors/cardiopulmonary baroreceptors
106
Q

where are arterial baroreceptors

A

within the carotid sinuses and the aortic arch

107
Q

where are low-pressure volume receptors/cardiopulmonary baroreceptors

A

within the atria, ventricles, and pulmonary artery

108
Q

what do arterial baroreceptors do

A

they are stretch receptors that only control short-term changes in blood pressure

cause some inhibition of the Renin-angiotensin & aldosterone system

109
Q

how do arterial baroreceptors work

A
  1. blood pressure drops
  2. baroreceptors decrease discharge rate
  3. travels to medulla
  4. causing increased sympathetic activity
    - Raised HR (and CO)
    - Increased contractility (and CO)
    - Arteriolar vasoconstriction due to innervation and raised angiotensin II (increased TPR)
  5. causing decreased parasympathetic activity
110
Q

what do cardiopulmonary baroreceptors do

A

control long term pressure changes

111
Q

what happens when cardiopulmonary baroreceptors are stimulated eg when there is high blood pressure

A
  • leads to the inhibition of the pressor
    region/ vasoconstrictor centre in the medulla - leading to a fall in blood pressure
  • Also inhibits the Renin-angiotensin & aldosterone system - since angiotensin II stimulates vasoconstriction which will increase blood pressure, also aldosterone stimulates more Na+ and thus H2O reabsorption thereby increasing blood volume
    and thus pressure
  • Also inhibits vasopressin/ADH - since it too stimulates more water reabsorption
  • Thus when stimulated the cardiopulmonary baroreceptors bring about a decrease in blood pressure by promoting vasodilation & fluid loss
112
Q

what is total peripheral resistance mainly dependent on and WHY

A

arteriole resistance

because ARTERIOLES ARE THE PRINCIPAL SITE OF RESISTANCE TO
VASCULAR FLOW

113
Q

effect of endothelin -1

A

released by endothelium cells results in vasoconstriction
[POTENT]

114
Q

what is hypoxia

A

when O2 supply decreases, there will be an accumulation of vasodilator
metabolites which will dilate vessels to increase local blood flow

115
Q

what does nitric oxide do

A

released by endothelial cells - triggers vasodilation [POTENT]

116
Q

what does Prostacyclin/ Prostaglandin I2 (PGI2): do

A

released by endotheliaal cells - triggers
vasodilation [POTENT

117
Q

why can adrenaline can be
both a vasodilator & vasoconstrictor

A

depends on which receptors are present

118
Q

what are peripheral chemoreceptors

A

In the aortic arch & carotid sinus (base of internal carotid artery - at the division between the internal and external carotid), stimulated by a fall in PaO2 & a rise in PaCO2 & a fall in pH causing blood pressure to increase

119
Q

what is pulmonary circulation

A
  1. blood leaves the right ventricle via the pulmonary trunk

2.this divides into the two pulmonary arteries, one supplying the
right and one supply the left lung.

  1. In the lungs the arteries continue to branch and connect to arterioles, leading to capillaries that unite into venules and then veins.
  2. the blood leaves the lungs via four pulmonary veins, which empty into the left atrium
120
Q

what is sytemic circulation :

A
  1. Blood leaves the left ventricle via the
    aorta.
  2. The arteries of the systemic circulation branch off the aorta, dividing into progressively smaller vessels. The smallest arteries branch into arterioles, which branch into roughly 10 billion very small vessels, the capillaries, which unite to form larger-diameter vessels known as venules.
  3. The arterioles, capillaries & venules
    are collectively referred to as the MICROCIRCULATION.
  4. The venules then unite to
    form larger vessels, veins.
  5. The veins from the various peripheral organs and tissues unite to produce two large veins, the inferior and superior vena cava which drain
    into the right atrium

cardiovascular lectures (15 decks)

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