Cardiovascular system Flashcards

1
Q

What forms the cardiovascular system?

A
  • Heart
  • Blood
  • Vessels
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2
Q

What is the left side of the heart responsible for?

A

Pumping oxygen-rich blood around the whole of the body.

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3
Q

What is the right side of the heart responsible for?

A

Pumping deoxygenated blood around to the lungs where it can be re-oxygenated and returned to the left side of the heart.

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4
Q

What is the order of the flow of blood through the heart?

A

Right atrium, AV valve (tricuspid), Right ventricle, Semi-lunar valve, Pulmonary artery, Lungs, Pulmonary vein, Left atrium, AV valve (bicuspid),Left ventricle, Semi-lunar valve, Aorta, Body, Vena cava, Right atrium.

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5
Q

Pulmonary circuit

A

Right side pumps blood to the lungs (heart,lungs,heart)

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6
Q

Systematic circuit

A

Left side pumps blood to the body (heart,body,heart)

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7
Q

Why is it said that the heart is two pumps working as one?

A
  • Two pumps- One on left/ One on right
  • Separated by a septum
  • Right side pumps blood to the lungs- Pulmonary circuit
  • Left side pumps blood to the body- Systematic circuit
  • They contract in unison
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8
Q

What is the purpose of the valves in the heart?

A

To ensure blood can only flow through one direction of the heart (prevent backflow of blood)

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9
Q

Why is the left side of the heart thicker than the right?

A

Because the left side is responsible for pumping blood around the whole body so the wall of the cardiac tissue (mycocardium) surrounding the left ventricle is much thicker than on the right side of the heart.

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10
Q

Heart structure

A
  • Cardiac muscle (involuntary)
  • Myogenic- It can stimulate it’s own impulses and doesn’t require stimulation by the brain.
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11
Q

Conduction of the heart

A
  • Conduction of the heart begins with an electrical impulse in the SINOATRIAL node.
  • Spreads over the muscular walls of both atria causing them to contract together.
  • Impulse reaches the atrioventricular node which holds the impulse temporarily. Delay of 0.1 seconds allows both atria to contract fully.
  • Impulse then continues passing via the bundle of his down the septum wall and spreads throughout the purkinje fibres.
    This allows both ventricles to contract forcing the blood out of the heart and around the body.
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12
Q

Systole

A

Contraction (forcing blood out)

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13
Q

Diastole

A

Relaxation (fill with blood)

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14
Q

Cardiac cycle

A

refers to the electrical and mechanical events that take place in the heart during 1 complete heart beat.
- Takes approx 0.8s and 72bpm.

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15
Q

Cardiac cycle stages

A
  1. Atrial diastole
    2 Ventricular diastole
  2. Atrial systole
  3. Ventricular systole
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16
Q

How long does atrial diastole and ventricular diastole take?

A

0.5 seconds

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17
Q

How long does atrial systole and ventricular systole take?

A

0.3 seconds

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18
Q

Atrial diastole (relaxation)

A
  • Atria fill with blood
  • Atrioventricular valves are closed
  • Semi lunar valves are open
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19
Q

Ventricular diastole (relaxation)

A
  • Rising pressure in the atria causes the AV valves to open and the ventricles to fill with blood.
  • Atrioventricular valves open
  • Semi-lunar valves closed
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20
Q

Atrial systole (contraction)

A
  • Atria contract, forcing blood into the ventricles.
  • Atrioventricular valves open
  • Semi lunar valves closed
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21
Q

Ventricular systole (contraction)

A
  • Ventricles contract, increasing pressure in the ventricles and forcing blood into the aorta and pulmonary artery.
  • AV valves are forced to close
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22
Q

During exercise, what must the body do to meet the bodies demands for oxygen as heart rate must increase?

A

SA node must fire impulses more rapidly.

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23
Q

Stroke volume

A

The amount of blood that leaves the heart during 1 contraction
- Approx 70-90ml

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24
Q

Heart rate

A

The number of beats per minute

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25
Q

Cardiac output

A

The amount of blood pumped out of the heart per minute.
CO= SV X HR

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26
Q

Bradycardia

A

Slow resting heart rate <60bpm

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27
Q

How do you calculate moment?

A

Force (N) x distance from pivot (M)
Moment=Nm

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28
Q

How is heart rate controlled?

A

SA node does generate it’s own impulses.
- At approximately 100bpm

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29
Q

Cardiac control centre

A
  • Located in the Medulla Oblongata
  • Forming part of the autonomic nervous system.
  • Central to the regulation of heart rate.
  • Under involuntary control.
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30
Q

Two components of the Cardiac control centre

A
  • Sympathetic nervous system
  • Parasympathetic nervous system
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31
Q

Sympathetic nervous system

A

Responsible for increasing the heart rate via the cardiac accelerator nerve

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32
Q

Parasympathetic nervous system

A

Responsible for decreasing the heart rate via the vagus nerve (returning heart rate back to normal resting levels)

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33
Q

What sensory receptors does the cardiac control centre receive information from?
(Neural components)

A
  • Proprioceptors
  • Chemoreceptors
  • Baroreceptors
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34
Q

Proprioceptors

A
  • These sense movement in the muscles and inform the CCC.
  • ## Exercise beings about an increase in muscular activity which requires an increase in heart rate.
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35
Q

Chemoreceptors

A
  • These sense the acidity of the blood (pH) and provide information to the CCC.
  • Located in the aorta and Carotid arteries of the neck.
  • Concerning the concentration of carbon dioxide, oxygen and lactic acid in the blood.
36
Q

What happens if levels of Carbon dioxide and lactic acid increases?

A
  • It will cause the pH of the blood to fall so heart rate will increase.
37
Q

Baroreceptors

A
  • They sense blood pressure.
  • Located in vena cava, aorta and carotid artery.
  • If increased blood pressure, heart rate decreases.
38
Q

Hormonal control of heart rate

A
  • Adrenaline (released by the adrenal glands)
  • Increases heart rate and rate of respiration
  • Prepares body for impending exercise
  • Increasing blood glucose levels by stimulating the breakdown of glycogen in the liver. (fuels muscular contraction)
39
Q

What occurs following exercise with the SA node?

A
  • Following exercise, stimulation of the SA node by the sympathetic nerve decreases.
  • Allowing the parasympathetic nerve to take over which causes the heart rate to fall.
  • Action of another hormone (acetylcholine) released by the parasympathetic nerve causes the decrease in heart rate.
40
Q

Intrinsic control of heart rate

A
  • Temperature
  • Increase in temperature causes an increase in heart rate.
  • Venous return
  • Increase in venous return increases heart rate and stroke volume.
41
Q

Anticipatory rise

A

Heart rate increase from adrenaline

42
Q

What is the heart rates response to sub maximal/ steady exercise?

A

It will increase then stay constant (straight line)

43
Q

What is the heart rates response to maximal/ steady exercise?

A

It will increase then gradually decrease.

44
Q

What two variables is the performance of the heart largely dependant on?

A
  • Stroke volume
  • Heart rate
45
Q

What 3 reasons explain the short term increase in stroke volume during exercise?

A
  • Increased venous return
  • Elasticity of the cardiac fibres
  • Contractility of cardiac tissue
46
Q

Increased venous return

A
  • The volume of blood returning to the right atrium increases in speed.
  • The greater the venous return (more blood) the greater the stroke volume since more blood is available to be pumped out.
47
Q

Elasticity of the cardiac fibres

A
  • High venous return will cause a stretch upon the heart walls so the greater the force of contraction (increases stroke volume)
  • Starlings Law
48
Q

Contractility of cardiac tissue

A
  • With increased contractility, a greater force of contraction can occur ejecting more blood.
  • Increases stroke volume
49
Q

Long term effects of exercise

A
  • Bradycardia
  • Hypertrophy so stroke volume increases so more oxygen to working muscles
  • Increase in mitochondria
  • Increase in red blood cells
  • Increase of capillarisation in lungs (allows for an increase in gas exchange)
    Beneficial as oxygen in and carbon dioxide out so less fatigue
  • Increase in myoglobin
50
Q

Why is your heart rate changing during exercise?

A
  • Heart rate will increase as there will be an increased need for energy so blood transport will increase.
  • Due to this, there will be more oxygen to support aerobic respiration.
  • Cardiac control centre has receptors (medulla oblongata)
  • Parasympathetic nerve (movement) whether it’s high or low.
  • Chemoreceptors detects acidity of blood.
  • Barcoreceptors detects pressure.
  • If heart rate is increasing sympathetic nervous system is responsible for it via the cardiac accelertor nerve.
  • If heart rate is decreasing parasympathetic nervous system is responsible for it via the vagus nerve.
51
Q

When heart rate increases due to exercise what is it dependant on?

A

The exercise intensity

52
Q

How do you work out your maximum heart rate?

A

By subtracting your age from 220

53
Q

What does sub-maximal exercise mean?

A

Where exercise is performed at a constant intensity over a prolonged period of time so heart rate may plateau into a steady state where oxygen demand is being met by oxygen supply.

54
Q

Relationship with stroke volume and intensity of exercise?

A
  • Stroke volume increases with intensity
  • But only up to 40-60% of maximum effort
  • Then stroke volume plateaus.
55
Q

What is the impact of performance on increased stroke volume?

A
  • Increased cardiac output
  • Increased blood supply
  • greater oxygen delivery.
56
Q

Cardiovascular drift

A
  • Drifting upwards of heart rate even though exercising at a constant rate.
  • Occurs due to a reduced stroke volume resulting from excessive sweating and dehydration.
  • Heart rate must increase to maintain cardiac output.
57
Q

How do you reduce the effects of cadiovascular drift?

A

To remain hydrated in order to maintain blood volume.

58
Q

Vessels of the circulatory system

A
  • Arteries
  • Arterioles
  • Capillaries
  • Veins
  • Veinules
59
Q

Arteries and Arterioles (function)

A
  • They carry blood away from the heart
  • Supply bodies tissues with oxygenated blood apart from the pulmonary artery
  • Main artery is the aorta ( large x-sectional area)
  • When arteries get further away from the heart (smaller x-sectional area) they are arterioles.
60
Q

Arteries (structure)

A
  • Thick/ elastic muscular walls to withstand high pressure
  • Arterioles can use this muscle to contract, vasodilate, vasoconstrict to divert blood flow.
  • Small lumen to maintain the high pressure.
  • Arterioles can close and open the lumen so blood can flow in different directions.
61
Q

Capillaries (function)

A
  • Gas exchange)
62
Q

Capillaries (structure)

A
  • Walls are one cell thick- Diffusion distance for oxygen and other nutrients is short.
  • High surface area dueto the vast number of capillaries.
  • Narrow diameter so blood flow is slow
63
Q

Veins (function)

A
  • Transport blood towards the heart (low pressure)
  • Carry deoxygenated blood apart from the pulmonary vein (oxygenated)
64
Q

Veins (structure)

A
  • Wide lumen
  • Thin elastic and muscle wall as blood pressure is much lower as veins are further away from the heart.
  • Valves (prevent backflow of blood) so blood can flow in one direction.
65
Q

Vascular shunt

A
  • Redistribution of blood throughout the body so that the working muscles receive an increased proportion.
  • Achieved through vasodilation and vasoconstriction.
  • Regulated by the process of vasomotor control.
  • Vasomotor centre is located in Medulla Oblongata.
  • Chemoreceptors detect carbon dioxide levels increase in the blood
  • This informs the Vasomotor centre to stimulate the
    sympathetic nerves - Cause the smooth muscle muscle within the arteriole walls to vasoconstrict and vasodilate
66
Q

Mechanisms to help improve venous return

A
  • Valves
  • Smooth muscle
  • Respiratory pump
  • Skeletal muscle pump
67
Q

Skeletal muscle pump

A
  • Walls of veins are thin so contraction and relaxation of muscles during exercise creates a massaging effect on them.
  • Which squeezes and pumps blood back towards the heart.
68
Q

Valves

A
  • Exist within valves
  • Snap shut ensuring there is no backflow of blood and that the flow is one way which is back towards the heart.
69
Q

Smooth muscle

A
  • Located within the walls of the veins
  • Work with the muscle pump to squeeze blood back towards the heart
70
Q

Respiratory pump

A
  • Increased rate and dephth of breathing during exercise increases pressure in the thorax and abdomen.
  • Which compresses the veins and squeezes the blood into the veins.
71
Q

Vasodilation

A
  • An increase in the diameter of an artery and arteriole walls (widening) supplying the more active muscles.
72
Q

Vasoconstriction

A
  • A reduction in the diameter of an artery and artery walls supplying organs such as the intestines, kidneys and liver.
73
Q

Venous return

A

The flow of blood through the systematic veins back to the heart via the vena cava

74
Q

2 factors why effeicient venous return can be a challenge to the body

A
  • Blood pressure is much lower in the veins as their further away from the heart pump
  • Gravity as a large quantity of the blood is below the heart so has to go uphill against gravity
75
Q

Pre-capillary sphinctors

A
  • Small ring of smooth muscle that exists on the arterioles at the point of entry to the capillary network.
  • They regulate blood flow into the capillaries by either vasoconstriction or vasodilation.
76
Q

Reasons why the redirection of blood is important to the performer

A
  • Increases oxygen supply to the working muscles
  • Provides the working muscles with the necessary fuel to contract (glucose and fatty acids).
  • Removes carbon dioxide and lactic acid from the working muscles.
77
Q

Why is slow flow in the capillaries useful?

A

It allows for efficient diffusion

78
Q

Blood pressure definition

A

The force exerted by the blood on the inside walls of the blood vessels.

79
Q

What are the two factors that influence fluid flow rate?

A
  • Pressure (higher pressure= cardiac systole (120) (lower pressure= cardiac diastole (80)
  • Vessel structure (total cross-sectional area)
80
Q

What are the two main factors of blood pressure?

A
  • Blood flow (cardiac output)
  • Peripheral resistance
81
Q

3 factors related to resistance

A
  • Blood viscosity
  • Blood vessel length
  • Blood vessel diameter
82
Q

Calculation (blood pressure)

A

Blood pressure = cardiac output x peripheral resistance

83
Q

Why does blood pressure fall as the blood flows away from the heart through the arteries?

A
  • Due to the decreasing effect of the pumping action of the heart
  • Increase in the total cross-sectional area of blood vessels as the number of arterioles and capillaries increases. (reduces peripheral resistance)
84
Q

Why does the blood velocity increase again as the blood enters the veins and venules?

A

As the total cross-sectional area for these vessels decreases but doesnt quite reach the flow rate of the arteries as the pressure is lower.

85
Q

What is the realtionship between cross sectional area and flow rate?

A

As cross sectional area increases (arterioles and capillaries)- flow rate is slower
As cross sectional area decreases (venules and veins)- flow rate increases
Aorta= biggest area
Vena cava= Lowest area