Cardiovascular System Flashcards

1
Q

What is the cardiac cycle?

A

The sequence of events that make up one heart beat

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2
Q

What are the two phases of the cardiac cycle?

A

Relaxation
Contraction

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3
Q

How long is the diastole phase?

A

0.5 seconds

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4
Q

How long is the systole phase?

A

0.3 seconds

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5
Q

What type of phase is diastole?

A

Relaxation phase

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6
Q

What type of phase is systole?

A

Contraction phase

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7
Q

What is happening during the diastole phase?

A

Relaxation Phase
-Both atria passively fill with blood
-As the pressure increases in the atria the blood trickles down into the ventricles

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8
Q

What is the order of phases which occurs during the cardiac cycle?

A

Diastole
Atrial Systole
Ventricular Systole

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9
Q

What stage happens after diastole?

A

Atrial Systole

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10
Q

What happens during the atrial systole stage?

A

Both atria contract which actively forces the remaining blood down into the ventricles

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11
Q

What stage occurs after atrial systole?

A

Ventricular Systole

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12
Q

What happens during ventricular systole?

A

Both ventricles contract actively forcing blood out of the heart (either to the kings or the rest of the body) via the pulmonary artery or aorta

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13
Q

What is the cardiac conduction system responsible for?

A

Initiating the cardiac impulse and spreading it through he cardiac muscle for contraction (systole)

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14
Q

What does myogenic mean?

A

It has the capacity to generate its own electrical impulse.

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15
Q

Where is the impulse initiated?

A

SA (sino atrial) node

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16
Q

What happens once the electrical impulse is initiated by the SA node?

A

It travels/is transported across both atria before being received by the AV (atrial ventricular) node.

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17
Q

After travelling through both atria where is the impulse received?

A

AV node
Atrial Ventricular

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18
Q

What happens at the AV node?

A

The AV node delays the impulse by 0.1 second to allow for atrial systole ( where blood is ejected into the ventricles)

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19
Q

Where is the impulse released once atrial systole at the AV node has occurred?

A

Bundle of HIS

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20
Q

What is the purpose of the bundle of HIS?

A

The bundle of HIS splits the impulse down the left and right bundle branches to be distributed to the ventricles

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21
Q

Once the impulse has passed the bundle branches what does it reach?

A

Purkinje fibres

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22
Q

Once the impulse has reached the purkinje fibres what will happen?

A

Ventricular systole (ventricles contract)will occur causing blood to be ejected out of the heart and to the body/lungs

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23
Q

Why is there a brief break where there is no impulse?

A

To allow blood to enter the atria

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24
Q

How does the cardiac conduction system control the cardiac cycle?

A

A heart Beat starts with diastole. Diastole is the relaxation phase where atria passively fill with blood. This increases the pressure in the atrium, causing some trickle down to the ventricles. An impulse, is initiated in the SA node which proceeds to travel across both atria before reaching AV node. At the AV node there is a slight delay of 0.1 seconds, which allows atrial systole . This is when both atria contract actively forcing the remaining blood down into the ventricles, the signal proceeds to travel down the bundle of HIS before splitting between the bundle branches and the purkinje fibres to cause ventricular systole, which means both ventricles contract for some blood out of the heart via the aorta and pulmonary artery.

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25
Q

Define heart rate?

A

The number of times the heart contracts in one minute

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26
Q

What is heart rate measured in?

A

BPM

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27
Q

What is the resting untrained value for heart rate?

A

72bpm

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28
Q

What is the resting trained value for heart rate?

A

50bpm

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29
Q

What is the submaximal untrained value for heart rate?

A

100bpm-130bpm

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30
Q

What is the submaximal trained value for heart rate?

A

95 bpm - 120bpm

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31
Q

What is the maximal untrained and trained value for heart rate?

A

220 - AGE

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32
Q

What’s the definition of stroke volume?

A

Volume of blood ejected from the left ventricle per beat

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33
Q

What is stroke volume measured in?

A

ml

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34
Q

What is the resting untrained value of stroke volume?

A

70ml

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35
Q

What is the resting trained value for stroke volume?

A

100ml

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36
Q

What is the submaximal untrained value for stroke volume ?

A

100-120ml

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37
Q

What is the submaximal trained value for stroke volume ?

A

160-200ml

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38
Q

What is the maximal untrained value for stroke volume ?

A

100-120ml

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39
Q

What is the maximal trained value for stroke volume?

A

160-200ml

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40
Q

What is the definition of cardiac output ?

A

Volume of blood ejected from the left ventricle per minute

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41
Q

What is cardiac output measured in?

A

l/min

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42
Q

What is the equation for cardiac output?

A

Q = HR x SV
Cardiac Output = Heart Rate x Stroke Volume

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43
Q

What is the resting untrained value for cardiac output?

A

5 l/min

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44
Q

What is the resting trained value for cardiac output?

A

5 l/min

45
Q

What is the submaximal untrained value for cardiac output?

A

10-15 l/min

46
Q

What is the submaximal trained value for cardiac output?

A

15-20 l/min

47
Q

What is the maximal untrained value for cardiac output?

A

20-30 l/min

48
Q

What is the maximal trained value for cardiac output?

A

30-40 l/min

49
Q

What is venous return?

A

Amount/volume of blood returning to the heart

50
Q

What is Starlings Law?

A

If the Amount of blood returning to the (venous return) increases so does cardiac output

51
Q

What is the equation linked to Starlings Law?

A

Increase in Venous return = Increase in cardiac output

52
Q

When does stroke volume reach is maximal value/volume?

A

At sub-maximal exercise

53
Q

What is sub-maximal exercise ?

A

When heart rate is 60% of Maximum Heart Rate (MHR)

54
Q

What is maximal exercise?

A

When heart rate is 80-95% of Maximum Heart Rate (MHR)

55
Q

Explain the effect of sub maximal exercise (intensity) on heart rate (cardiovascular system)?

A
  • Before exercise we are at rest (72-50bpm dependent on whether athlete is trained)
  • A minute before anticipatory rise (due to adrenaline) causes heart rate to increase by a few bpm
  • During first 3-4 mins of exercise heart rate rapidly increases to meet demand of oxygen
  • After increase reaches sub-maximal and plateaus as oxygen supply is meeting the demand of muscles
  • During first 2-3 mins of recovery rapid decline in heart rate due to reduction in oxygen demand
  • Slow decline back to resting (as lactic acid is removed)
56
Q

What happens just before exercise begins?

A

Heart rate increases by a few bpm due to anticipatory rise (caused by hormone adrenaline)

57
Q

What happens in the first 3-4 mins of exercise?

A

Rapid increase in heart rate to submaximal level

58
Q

What happens during exercise once heart rate has reached sub-maximal level?

A

Heart Rate plateaus as oxygen is meeting the demand

59
Q

What occurs during first few minutes of recovery?

A

Rapid decrease in heart rate ( reduction in oxygen demands)

60
Q

Explain the effect of maximal exercise (intensity) on heart rate (cardiovascular system)?

A
  • Before exercise we are at rest (72-50bpm dependent on whether athlete is trained)
  • A minute before anticipatory rise (due to adrenaline) causes heart rate to increase by a few bpm
  • During first 3-4 mins of exercise heart rate rapidly increases to meet demand of oxygen (to sub-max)
  • It then increases gradually to try and meet oxygen demand
  • Once maximal heart rate is reached muscles fatigue due to lactate accumulation and heart rate begins to decline
  • During first 2-3 mins of recovery rapid decline in heart rate due to reduction in oxygen demand
  • Long and Slow decline back to resting (as lactic acid is removed)
61
Q

What happens to stroke volume at submaximal and maximal exercise occurs?

A

SV at resting is 70-100ml
As anticipatory rise occurs SV increases.
During exercise sharp increase before plateau as ventricle can’t contract further
Declines 2-3 min in recovery due to lower demand
Slower gradual decline to resting

62
Q

Why does stroke volume plateau at sub maximal exercise (40-60%)?

A
  • A decrease in the diastolic filling time (heart contracting too quickly) that occurs during exercise of increasing intensity
  • As heart rate is high there isn’t enough time for the ventricle to completely fill which limits starlings Law
63
Q

Why does a gradual decrease in heart rate occur during maximal intensity?

A

Maximum heart rate had been reached and the muscles begin to fatigue due to lactic acid

64
Q

What is a baroreceptor?

A

Receptors which detect a change in blood pressure

65
Q

What happens to blood pressure as we exercise?

A

It increases

66
Q

What do chemoreceptors detect?

A

They detect a change in chemical levels (eg. decreasing oxygen, increasing lactic acid and carbon dioxide)

67
Q

What do proprioreceptors detect?

A

Detect movement

68
Q

Where are proprioreceptors found?

A

Muscles
Tendons
Joints

69
Q

What is the CCC?

A

Cardiac control centre

70
Q

Where is the CCC located?

A

In the medulla oblongata

71
Q

Where does the CCC send an impulse after receiving information from the receptors during EXERCISE?

A

Cardiac accelerator nerve (via the SNS - sympathetic nervous system)

72
Q

What is the cardiac accelerator nerve part of?

A

The SNS
- sympathetic nervous system

73
Q

Describe how heart rate is regulated during exercise by neural control?

A

Baroreceptors detect change in blood pressure, chemoreceptors detect change in oxygen, carbon dioxide and lactic acid levels, proprioreceptors detect movement.
The information is then sent to the CCC (cardiac control centre) in the medulla oblongata
It the sends an impulse via the SNS (sympathetic nervous system) down the cardiac accelerator nerve
Impulse stimulates the SA node causing it to increase firing of signal

74
Q

What are the three factors affecting regulation of heart rate during exercise?

A

Neural Control
Intrinsic Control
Hormonal Control

75
Q

What is the main factor affecting regulation of heart rate during exercise?

A

Neural control

76
Q

Describe how heart rate is regulated during REST/RECOVERY by neural control?

A

Baroreceptors detect decline in blood pressure, chemoreceptors detect an increase in oxygen, but a decrease in carbon dioxide and lactic acid levels, proprioreceptors detect reduced movement.
The information is then sent to the CCC (cardiac control centre) in the medulla oblongata
It the sends an impulse via the PNS (parasympathetic nervous system) down the VAGUS NERVE
Impulse overrides the signal for the SA node to increase firing which causes a decrease in heart rate

77
Q

What nerve is associated with neural control during REST/RECOVERY?

A

Vagus nerve

78
Q

What nervous system is the vagus nerve part of?

A

Parasympathetic nervous system

79
Q

What is the hormonal factor is heart rate regulation?

A
  • It’s controlled by the autonomic nervous system (ANS) which stimulates the sympathetic nervous system (SNS)
  • Adrenaline is secreted from the adrenal gland which travels via the bloodstream to stimulate the SA node to increase firing
  • This increases heart rate, the force of contraction, Stroke volume and cardiac output
80
Q

Which nervous system is associated with hormonal control?

A

Autonomic Nervous System (ANS)

81
Q

How is adrenaline released?

A

From adrenal glands in kidneys

82
Q

How does adrenaline stimulate the SA node?

A

Directly stimulates the SA node via the bloodstream to increase firing

83
Q

What is the intrinsic factor in regulating heart rate?

A

An increase in venous return causes an increase in cardiac output as per Starlings Law
This causes the right atrium to stretch/bulge which triggers an increase in firing of the SA node
More blood enters the left ventricle causing it to stretch (increases stroke volume)
This leads to an increase in temperature (muscles and blood) which triggers a higher speed of nerve impulses to increase heart rate

84
Q

What is the purpose of arteries?

A

Carry oxygenated blood from heart to muscles

85
Q

What are the structural features of an artery?

A

Blood is under high pressure
Has a layer of smooth (elastic) muscles
Nablus vasodilation and vasoconstriction

86
Q

What do arterioles have?

A

Pre-capillary sphincters - ring of mouth muscle surrounding the capillary bed which allows vasodilation and vasoconstriction

87
Q

What are the structural properties of capillaries?

A

Have walls which are one cell thick
Gas exchange occurs here

88
Q

What are the three types of blood vessels?

A
  • Arteries/arterioles
  • Veins/venules
  • Capillary
89
Q

What is the purpose of veins/venules?

A

Carry deoxygenated blood from muscles and organs back to the heart (venous return)

90
Q

What structural features/properties do veins have?

A

Small layer of smooth muscle to allow venodilation and venoconstriction
Blood under low pressure
Have pocket valves to prevent the back flow of blood
Thick outer layer to help support blood in each pocket valve

91
Q

What is venous return?

A

Transport of blood from the capillaries through venules and veins back to the right atrium of he heart through the inferior vena cava

92
Q

What helps maintain venous return?

A

Venous return mechanisms

93
Q

What are the 5 venous return mechanisms?

A
  • Pocket valves
  • Smooth muscle
  • Skeletal muscle pump
  • Respiratory Pump
  • Gravity
94
Q

How do pocket valves maintain venous return?

A

One-way valves found in veins prevent the back flow of blood and direct it towards the heart

95
Q

How does muscle pump aid venous return?

A

When muscles contract and relax they press on nearby veins squeezing the blood towards the heart

96
Q

How does respiratory pump aid venous return?

A

When exercising inspiration and expiration becomes faster and deeper which causes pressure changes to occur in the thoracic cavity and abdomen. The pressure compresses/squeeze nearby veins to assist blood flow back to the heart

97
Q

How does smooth muscle aid venous return?

A

Contraction and relaxation of smooth muscle in the middle layer of vein walls helps to push blood through the veins and back to the heart

98
Q

How does gravity aid venous return?

A

Blood from the upper body is aided by gravity as it descends to the heart

99
Q

What is the redistributed of blood during exercise known as?

A

The vascular shunt mechanism

100
Q

At rest how much cardiac output is supplied to muscles

A

15-20%

101
Q

During exercise how much cardiac output is supplied to muscles?

A

80-85%

102
Q

What happens to cardiac output during exercise?

A

Q increase to muscles but decreases to non-essential organs.
Blood supply to the brain is maintained to keep up vital functions

103
Q

What is the VCC?

A

Vasomotor control system

104
Q

Explain how the blood is redistributed during exercise?

A
  1. The VCC receives information from:
    Chemoreceptors in muscles, aorta and carotid arteries which detect lactic acid and CO2 incline and oxygen and Ph levels decreased
    Baroreceptors in aorta and carotid arteries detect and increase in systolic blood pressure
  2. The VCC responds by sending signals via the SNS to
    Organs: Sympathetic stimulation increased which vasoconstricts pre-capillary sphincters and arterioles decreasing Q and redistributing blood flow away from non-essential organs
    Muscles : Sympathetic stimulation decreased which vasodilates pre-capillary sphincters and arterioles increasing cardiac output to capillaries of working muscles
105
Q

What is blood pooling?

A

the accumulation of blood in the veins (specifically the pocket valves) due to gravitational pull and the lack of venous return.

106
Q

Explain the process of the vascular shunt mechanism during exercise?

A
  • Chemoreceptors detect an increase in CO2, lactic acid but a decrease in oxygen
  • Baroreceptors detect an increase in blood pressure
  • Proprioreceptors detect an increase in movement
  • A signal is sent to the VCC in the medulla oblongata
  • This sends an increased sympathetic stimulation to the pre-capillary sphincters and arterioles in organs causing vasoconstriction and decreased blood flow to non- essential organs (20% of blood)
  • This sends a decreased sympathetic stimulation to the pre-capillary sphincters and arterioles in working muscles causing vasodilation and increased blood flow to working muscles (80% of blood)
107
Q

What is the percentage of oxygen split in the redistribution of blood?

A

80% working muscles
20% non-essential organs (blood supply to brain continues)

108
Q

Explain how venous return mechanisms can aid venous return and prevent blood pooling as part of recovery?

A

Venous return mechanisms work to maximise blood flow back to the heart
- this means the player won’t get dizzy or faint
- this means blood pressure is maintained to speed up the removal of lactic acid
- Decrease DOMs (delayed on-set muscle soreness)