CARDIOVASCULAR Flashcards

1
Q

What are the 5 elements of the oxygen transport system

A
  • Pulmonary ventilation
  • Aerobic metabolism
  • Peripheral blood flow
  • Hemoglobin concentration
  • Blood volume and cardiac output
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2
Q

What is flow velocity primarily impacted by

A

vessel diameter - vasodilation and vasoconstriction

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3
Q

A tubes resistance is … to its radius

A

inversely proportional to the fourth power of its radius

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4
Q

What forces fluid from capillaries

A

blood pressure

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5
Q

what forces fluid back into capillaries

A

osmotic pressure

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6
Q

What are the 3 key components to delivering blood to working muscles

A
  1. heart function
  2. blood flow distribution (including bp)
  3. Oxygen extraction at muscles
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7
Q

What are 4 anatomical changes to the heart with exercise

A
  1. Increase mass and volume - muscles getting bigger and stronger
  2. Increase size of left ventricle
  3. Modest increase left ventricle wall thickness (due to increase in muscle)
  4. Increase left ventricle end diastolic volume (EDV) at rest and with exercise
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8
Q

Why does the left ventricle increase in siize with exercise

A

More blood coming in and the heart working to pump it out - cavity become bigger and more used to receiving large amounts of blood

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9
Q

Why is there an increase in left ventricle end diastolic volume at rest and with exercise

A

Because of improvement in cavity size has greater end diastolic volume both at rest and exercise - allows heart to fill with more and eject more

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10
Q

What is the unit for cardiac output

A

L/min

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11
Q

Blood flow from heart has a ___ Relationship with exercise intensity

A

linear

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12
Q

What occurs to CO in steady state exercise. why?

A

plateaus as blood flow matches exercise metabolic requirements

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13
Q

When does stroke volume plateau

A

~ 50% of VO2max

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14
Q

Does stroke volume increase linear with graded exercise

A

no

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15
Q

When stroke volume plateaus how do you continue to increase/maintain CO to meet demands

A

HR can increase until max

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16
Q

Why is HR lower in endurance trained athletes compared to untrained for the same O2

A

Stroke volume is higher in endurance trained athletes allowing HR to be lower while maintaining CO

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17
Q

what are the 3 mechanisms for an increase in SV with training

A
  1. Pre-load
  2. Enhanced cardiac filling in diastole filling
  3. Greater systolic emptying
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18
Q

Does an increase in preload take a long time or a short time

A

quick! 2-3 weeks

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19
Q

How is preload increased with exercise

A

Increase with plasma volume and greater blood volume

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20
Q

How does plasma volume increase with exercise

A

Kidney realizes that you are active and helps by secreting anti-diuretic hormone and aldosterone from pituitary glands and improves kidneys capability to hold water which will then be transported into bloodstream to increase blood volume

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21
Q

What is the result of the increase in blood volume with exercise

A
  1. Enhances circulating dynamics
  2. Enhances thermoregulatory dynamics
  3. Facilitates oxygen delivery to muscle during exercise
  4. contributes to training-induced enlargement of left ventricle (more strain from having to pump more blood)
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22
Q

What are the mechanisms behind enhanced cardiac filling in diastole filling

A
  • Increased venous return (pre-load)
  • Slower heart rate (for given workload)
  • Increase compliance of left ventricle
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23
Q

Why do you get greater systolic emptying with exercise

A

increase end diastolic volume stretches myocardial fibers = more powerful ejection stroke when heart contracts

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24
Q

What is the frank-starling law

A

realtionship between muscle force and resting fibre length

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25
Q

Blood pressure represents …

A

the force exerted by blood against the arterial walls during a cardiac cycle

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26
Q

What is the equation for resistance

A

(length of system x viscosity of blood) / (radius^4)

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27
Q

A small change in the diameter of a vessel results in a ____ change in resistance

A

large

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28
Q

Do length and blood viscosity change often?

A

no not substantially

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29
Q

Can radius change a lot?

A

yes - vasoconstriction + dilation

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30
Q

What is the equation for blood pressure

A

Cardiac output x total peripheral resistance

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31
Q

What indicates peripheral resistance

A

diastolic blood pressure

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32
Q

Diastolic blood pressure is…

A

the ease that blood flows from the arterioles into the capillaries

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33
Q

What is afterload

A

the resistance the heart has to pump against

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34
Q

What is afterload primarily based upon

A

blood pressure in the major arteries

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35
Q

what is chrontopic

A

time - rate of heart rate

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36
Q

What is inotropic

A

the force or energy of muscular contraction

37
Q

What increases chronotopic and inotropic

A

sympathetic influence

38
Q

what decreases hronotopic and inotropic

A

parasympathetic influence

39
Q

What provides the greatest control over HR

A

the central command

40
Q

Cardiovascular centre receives reflex sensory input from…

A

peripheral receptors in blood vessels, joints, and muscles

41
Q

What types of receptors which communicate with the cardiovascular centre are found in the muscle and its vasculature

A

chemoreceptors and mechanoreceptors

42
Q

How are appropriate cardiovascular and respiratory responses to exercise produced

A

through modification of either parasympathetic or sympathetic outflow

43
Q

What does the amount of cardiac ouput received by an area depend on

A

the number and caliber of arterioles supplying that area

44
Q

What is intrinsic regulation of arterioles

A
  • Directly impact arteriole smooth muscle
  • local metabolic changes
  • Local physical changes (stretch)
  • Signalling via endothelial cells lining vessels
45
Q

What is extrinsic regulation of arterioles

A
  • Sympathetic and parasympathetic influences

- Governed by central command (can send signals to smooth muscle to change)

46
Q

Put blood flow at rest in order from most to least

A
Liver 
Kidneys 
Muscle 
Brain 
Other 
Skin 
Heart
47
Q

Put blood flow with strenuous exercise in order from most to least

A
Muscle 
Heart and brain 
Other 
Skin and Liver 
Kidney
48
Q

What is total cardiac output at rest? exercise?

A

5000 mL to 25 000 mL

49
Q

At rest, what proportion of capillaries in muscles are open

A

1 in 30-40 capillaries in muscles

50
Q

Why are not all capillaries open all the time

A

only have 5L of blood at rest, dont want to send it to places where it is not needed.

51
Q

What opens and closes capillaries

A

precapillary sphincters

52
Q

What are main triggers for the opening of blood vessels

A
  • Blood pressure

- Local metabolites - getting more acidic

53
Q

What is venous return important

A

important to maintain CO

54
Q

What causes the exercise enhanced venous return

A
  • Muscle pump

- Change in diameter of veins due to constriction from vascular smooth muscle

55
Q

What causes the large increase in muscle blood flow during maximal exercise

A
  1. increased cardiac output
  2. Redistribution of blood from non-active areas
  3. Increased capillarization within trained muscles
56
Q

What are the values for prehypertension

A

S - 120-130

D 80-90

57
Q

What are the values for stage 1 hypertension

A

S - 140-159

D 90-99

58
Q

What are the values for stage 2 hypertension

A

S - >160

D - >100

59
Q

What occurs to blood pressure with graded exercise

A

Rapid increase of SBP right as they start exercising.
Linear increase in SBP as you increase exercise intensity
Diastolic decreases slightly before there is less resistance in system because muscles are working and radius of vessels are increasing

60
Q

What causes the increase in SBP at the onset of exercise

A

To result in greater CO

61
Q

when do you consider stopping graded exercise test

A

SBP >250

62
Q

Can you better decrease SBP or DBP with regular aerobic training?

A

SBP

63
Q

Why does SBP decrease with regular aerobic exercise

A

the explanation is still unclear but somehow reduces sympathetic nervous system activity

64
Q

Why does BP go higher with resistance type activity

A
  • Sustained muscular force compresses peripheral arterioles
  • This increases resistance to blood flow
  • Elevates work of the heart to pump against increased TPR
65
Q

What is the valsalva maneuver

A

Hold breath in order to stabilize core to allow greater lifting of a weight - Generate compressive forces to increase intrathoracic pressure

66
Q

What is the difficulty of valsalva maneuver

A

It causes thin wall, low pressure thoracic veins to collapse. When you bare down you can constrict vena cava from blood flow

67
Q

What is the result of the valsalva maneuver

A
  • This results in acute drop in BP
68
Q

What is the mechanism for the acute drop in BP caused by the valsalva Maneuver

A
  • Reduced venous return

- Lowers SV

69
Q

What does SBP and DBP increase more in rhythmic upper body activity than compared to rhythmic lower body activity

A
  • Smaller vasculature offers greater resistance to blood flow
  • Requires larger systolic pressure and increased work for the heart
70
Q

The goal is to deliver oxygen into ..

A

The citric acid cycle

71
Q

What are the 2 key mechanisms for increasing supply of oxygen to working muscles

A
  • Increased blood flow

- Greater oxygen extraction

72
Q

a-vO2 diff increases as…

A

as your increase demand on the system

73
Q

can venous oxygen levels diff get to 0? why?

A

no - you always have some blood perfusing to organs that is not doing a ton of extraction

74
Q

as your oxygen consumption increases what happen to a-vO2 different

A

increases

75
Q

What are 4 factors affecting a-vO2 difference

A
  • Hemoconcentration (movement of fluid from plasma to interstitial space) with exercise
  • Diversion of cardiac output to active tissue
  • Increase in skeletal muscle microcirculation (with training)
  • Increased number and size of mitochondria (extract more oxygen) (with training)
76
Q

Can training effect potential a-vO2 diff? why?

A

yes
Increased capillarization
Increase size and # mitochondria

77
Q

Is the change in a-vO2 diff a quick change with training or slowl

A

quick

One of the first changes we see and one of the first we lose

78
Q

What are adaptions by short-term and immediate energy systems with aerobic training

A
  • Increase levels of anaerobic substrates
  • Increase quantity and activity of key enzymes
  • Increase capacity to generate high levels of lactate
79
Q

What anaerobic substrates increase with aerobic training (think for immediate energy system)

A
  • Higher ATP

- Higher PCr

80
Q

What allows the increase capacity to generate high levels of lactate following aerobic training

A
  • Increase enzymes and clearance capacity

- “pain” tolerance

81
Q

What are 4 adaptions to long-term energy system (aerobic) with training?

A
  • Metabolic changes
  • Blood lactate concentration
  • Cardiovascular adaptions
  • Pulmonary adaptions
82
Q

What are 4 metabolic changes seen in long-term energy system with trainigg

A
  • Increased mitochondrial size
  • Increased aerobic system enzymes
  • Increased fat and carbohydrate catabolism
83
Q

What is fat carbohydrate catabolism

A

ability to burn fat

84
Q

What are the changes in blood lactate concentration seen in the long-term energy system with training

A
  • Decreased rate of lactate formation for given exercise intensity
  • increased lactate clearance
85
Q

What is the % difference of number of mitochondria between trained and untrained individuals

A

103%

86
Q

What is the % difference max stroke volume between trained and untrained individuals

A

50%

87
Q

What is the % difference max cardiac output between trained and untrained individuals

A

75%

88
Q

What is the % difference of VO2max between trained and untrained individuals

A

107%