acute cardiovascular response to exercise Flashcards

1
Q

three factors regulating venous return during exercise

A
  • constriction of the veins (venoconstriction)
    -pumping action of contracting skeletal muscle (muscle pump)
  • pumping action for the respiratory system (respiratory pump)
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2
Q

what is Cardiac output (Q)

A
  • the amount of blood pumped by the heart each minute
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3
Q

at rest CO should be at?
during exercise?

A
  • 5L per/min at rest
  • 20-35 L/min during exercising
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4
Q

Components of CO

A
  • product of HR and SV
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5
Q

stroke volume is the volume of

A

blood ejected with each heartbeat

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6
Q

another variable that affects SV is

A

aortic pressure (MAP)

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7
Q

if you have an increase of mean arterial pressure, what happens to stroke volume?

A

decrease

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8
Q

final factor that influxes stroke volume is the effect of circulating

A
  • catecholamine (N/NE)
  • direct sympathetic stimulation of the heart by cardiac accelerator nerves
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9
Q

overall, what three factors affect CO

A
  • EDV
  • Cardiac contractility
  • cardiac after load (aortic blood pressure)
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10
Q

increase of CA influx into the myocardial cell would cause?

A

cardiac contractility

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11
Q

increase in cardiac afterload results in a

A

decrease in stroke volume

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12
Q

Factos affecting cardiac rate

A
  • parasympathetic
  • sympathetic nerves
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13
Q

factors affecting stroke volume

A
  • sympathetic nerves
  • frank starling
  • EDV
  • MAP
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14
Q

blood flow is

A

the change of pressure over resistance

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15
Q

what happens to blood flow when vascular resistance increase

A

blood flow decrease

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16
Q

blood flow can be increased by

A
  • increase in blood pressure
  • decrease in resistance
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17
Q

regulation of HR - PSNS

A
  • via vagus nerve
  • slows HR
  • decreases contractility of the myocardium indirectly by inhibiting SNS
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18
Q

regulation of HR - SNS

A
  • via cardiac accelerator nerves
  • increases HR by stimulation SA and AV node
  • increases contractility of the myocardium directly
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19
Q

Cardiovascular control center is in the

A

medulla oblongata

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20
Q

medulla oblongata consists of 4 areas

A
  • pressor area (vasoconstrictor)
  • depressor area (vasodilator)
  • cardiac acceleration
  • cardiac inhibitory center
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21
Q

increased oxygen delivery to exercising skeletal muscle is accomplished via two mechanism

A
  • increase in CO
  • redistribution of blood flow form inactive organs to the working skeletal muscle
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22
Q

Fick Equation

A

VO2 = Q x (a-VO2diff)

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23
Q

during exercise, blood flow to contracting muscle is increased, and blood flow to less active tissues is

A

reduced

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24
Q

auto regulation refers to

A

intrinsic control of blood flow by increases in local metabolites

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25
Q

these factors work together to promote vasodilation to increase blood flow to the working muscles?

A

NO, prostaglandins, ATP, adenosine, and endothelium derived

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26
Q

what does NTS stand for

A

nucleus tractus solitarius - receiving inputs from afferent

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27
Q

vagal stimulation only goes

A

to the heart

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28
Q

sympathetic stimulation goes to the

A

heart and the blood vessels

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29
Q

glossopharyngeal nerve

A

carotid sinus

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30
Q

vagus nerve

A

aortic baroreceptors

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31
Q

a decrease in action potential frequency from the barorecepotros, should elicit

A

an increase in SNS activity

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32
Q

SNS response to decrease in bp effects on SA node

A

increase heart rate

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33
Q

SNS response to decrease in bp effects on myocardium

A

heart rate contractile

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34
Q

SNS response to decrease in bp effects on arteries

A

vasoconstrict

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35
Q

SNS response to decrease in bp effects on veins

A

stiffen

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36
Q

chemoreceptor reflex

A
  • sensitive to decrease O2, increase CO2, increase hydrogen ion
  • signals excite the vasomotor center
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37
Q

volume reflex

A
  • atrial stretch = dilation of afferent arterioles in the kidney
  • signals hypothalamus to decrease ADH
  • atria release atrial natriuretic peptide (ANP)
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38
Q

abdominal compression reflex

A

baroreceptor and chemoreceptor reflexes also excite motor nerves to the abdomen

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39
Q

respiratory

A
  • inspiration: decrease in BP
  • early expiation: increase in BP
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40
Q

bainbridge reflex

A
  • increase atrial stretch = increase HR and strength of contraction
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41
Q

increase in HR at onset of exercise

A
  • initial increase due to parasympathetic withdrawal
  • later increase due to increased SNS firing (outflow)
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42
Q

intrinsic rate of the heart is

A

90 to 100 bpm

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43
Q

Beta adrenergic blocking drugs (beta blockers)

A
  • competes with E/NE for beta adrenergic receptors in the heart
44
Q

function of beta blockers

A

reduce heart rate and contractility thus lowering the work of the heart and lowering myocardial oxygen demand

45
Q

beta is prescribed for patients with

A

coronary artery disease, hypertension, and post heart attack

46
Q

patients on beta blockers will have a lower cardiac output during

A

rest and exercise

47
Q

the balance between SNS and PNS is known as

A

sypathovgal balance

48
Q

the time between heart beats is determine by what interval

A

R to R interval

49
Q

A wide variation in HRV is considered

A

healthy

50
Q

Low HRV is a predictor of

A

cardiovascular morbidity and mortality

51
Q

what is End diastolic volume

A
  • volume of blood in the ventricles at the end of diastole
  • preload
  • depends on filling time and filling pressure
52
Q

filling time depends on

A

HR

53
Q

filling pressure depends on

A

central venous pressure

54
Q

average aortic blood pressure

A

pressure the heart must pump against to eject blood
- afterload
- MAP

55
Q

strength of the ventricular contraction (contractility) is enhanced by

A
  • circulating E/NE
  • direct sympathetic stimulation of the heart
56
Q

SV =

A

EDV - ESV

57
Q

frank starling mechanism is

A

greater EDV results in a more forceful contraction due to stretch of ventricles (length tension)

58
Q

EDV depends on

A

venous return (ventral venous pressure) and filling time

59
Q

venoconstriction is stimulated by

A

SNS

60
Q

what is skeletal muscle pump

A
  • rhythmical muscle contractions push blood toward the heart
  • veins have one way valves
61
Q

what is respiratory pump

A

changes in intrathoracic pressure pull blood toward the heart

62
Q

venoconstriction

A
  • veins collapse when there is no blood in them
  • can store a lot of blood
  • have only a thin layer of smooth muscles (tunica media)
63
Q

vein stiffen when stimulated by

A

SNS (no true constriction)

64
Q

how does veins collapse

A

no blood in them

65
Q

Venous return is

A

the venous pressure and RA pressure over venous resistance

66
Q

a decrease in RA pressure leads to

A

an increase in venous return and vice versa

67
Q

how does venous return work ? 1-6

A
  • inspiration
  • descent of the diaphragm
  • decrees in intrathoracic pressure
  • decrease in right atrial pressure
  • increase in abdominal pressure
  • blood in inferior vena cava squeezed from abdomen into the right atrium
68
Q

filling time can be describe as

A
  • it relates to time in diastole (amount of time to fill)
  • relaxation time (the fast the heat can relax, the more time it has to fill)
69
Q

true or false: a short relaxation time is more important during exercise than at rest

A

true - so it can fill

70
Q

increase EDV = increase of stroke =

A

increase of contractility

71
Q

the higher the after load,

A

it will decrease stroke volume

72
Q

increase of ESV results in

A

decrease of SV

73
Q

increase in TPR results an

A

increase in after load

74
Q

influence of mean aortic pressure (after load)

A
  • the higher the after load, the harder the heart must contract to eject a given volume of blood
75
Q

a high afterload will cause an increase or decrease of ESV

A

increase

76
Q

a increased of total peripheral resistance will increase or decrease after load

A

increase

77
Q

myocardial centrality is a direct stimulation of

A

cardiac accelerator nerves to the heart and SNS to adrenal medulla

78
Q

once stimulated by cardiac accelerator nerves, what does E/NE do?

A

increase of extracellular calcium entry to myocardial cell

79
Q

increase of extracellular Calum entry into the myocardial cell results an increased of

A

intracellular calcium

80
Q

increase of intracellular calcium results an

A

increased of x bridge formation causing myocardial contractility

81
Q

The study of the interrelationships between pressure, resistance, and flow and the physical principles of blood flow is called

A

hemodynamics

82
Q

blood flow depends on

A

a pressure difference

83
Q

blood flows from a region of

A

high pressure to region of low pressure

84
Q

resistance is

A

length x (viscosity/Radius to the 4th power)

85
Q

length typically

A

doesn’t change

86
Q

viscosity changes due to

A

dehydration

87
Q

radius has a

A

large impact on resistance (vasoconstriction/vasodilation)

88
Q

the perfect of blood that is composed of cells is called the

A

hematocrit

89
Q

3 cell types of the blood sample

A

white blood cells, platelets, red blood cells and plasma

90
Q

blood is several time more

A

viscous than water

91
Q

major contirubot to vhsiscosit is the

A

RBC number

92
Q

normal metocrit for male and female

A
  • 42-48
  • 38-42
93
Q

increase in either vessel length or blood viscosity results an

A

increase in resistance

94
Q

increase of resistance results

A

decrease in blood flow

95
Q

MAP decreases through the

A

systemic ciruclaiton

96
Q

largest BP drops occurs across the

A

arterioles

97
Q

arterioles are called

A

resistance vessels

98
Q

what regulate blood flows

A

arterioles

99
Q

purpose of capacitance vessels

A

storage of blood

100
Q

CO = HR x

A

SV

101
Q

CO = ___ x EDV-ESV

A

HR

102
Q

EDV depends on

A

preload

103
Q

preload depends on

A

filling time and filling pressure

104
Q

filling time depends on

A

HR

105
Q

filling pressure depends on

A

venous return

106
Q

ESV depends on

A

heart contractility and after load