cardiovascular system Flashcards
(156 cards)
1
Q
what does the cardiovascular system include
A
blood vessels and the heart
2
Q
what does the heart do during exercise
A
works to pump blood through the various blood vessels to deliver oxygen and nutrients to the working muscles and gather waste products such as carbon dioxide
3
Q
what is the heart described as being
A
myogenic
4
Q
what does myogenic mean
A
originating in the muscle tissue
5
Q
where does the electrical impulse in the heart start
A
the sinoatrial node
6
Q
explain what happens in the sinoatrial node
A
the electrical impulse starts here then spreads throughout the heart which is described as a wave of excitation
7
Q
what does the impulse do from the sinoatrial node
A
spreads through the walls of the atria causing them to contract
atrial systole
8
Q
what is it called when the atria contract
A
atrial systole
9
Q
after the sinoatrial node where does the impulse go next
A
passes through the atrioventricular node where the impulse is delayed approximately 0.1 seconds to enable the atria to fully contract before ventricular systole begins
10
Q
what does the atrioventricular node do
A
delays the electrical impulse for approximately 0.1 seconds to allow the atria to fully contract before ventricular systole begins
11
Q
after the atrioventricular node, where does the electrical impulse go
A
travels down the bundle of his which branches into two bundle branches
12
Q
after the bundle of his where does the electrical impulse go
A
the purkinje fibres which spread spread throughout the ventricles causing them to contract (ventricular systole)
13
Q
what do the purkinje fibres do
A
they spread throughout the ventricles, causing the ventricles to contract which is called ventricular systole
14
Q
what is the sinoatrial node also known as
A
the pacemaker of the heart
15
Q
give the order in which the cardiac impulse travels in
A
sinoatrial node
atrioventricular node
bundle of his
purkinje fibres
16
Q
what does the conduction system do during exercise
A
ensure that the heart rate increases to allow the working muscles to receive more oxygen
17
Q
what does the sympathetic nervous system do
A
stimulates the heart to beat faster
18
Q
what does the parasympathetic nervous system do
A
returns the heart rate to its resting level
19
Q
what are the parasympathetic and sympathetic nervous system co-ordinated by
A
the cardiac control centre
20
Q
where is the cardiac control centre located
A
in the medulla oblongata
21
Q
what is the cardiac control centre stimulated by
A
chemoreceptors, baroreceptors and proprioceptors
22
Q
what will a signal sent to the sympathetic system do
A
increase the heart rate
23
Q
what will as signal sent to the parasympathetic system do
A
decrease the heart rate
24
Q
explain what chemoreceptors do
A
detect an increase in blood carbon dioxide
a signal goes to the cardiac control centre
then onto the sympathetic system
to the sinoatrial node which increases the heart rate
25
explain what baroreceptors do
detect an increase in blood pressure
send a signal to the cardiac control centre
which sends a signal to the parasympathetic nervous system
which sends a signal to the sinoatrial node to decrease the heart rate
26
explain what proprioceptors do
detect an increase in muscle movement
this sends an impulse to the cardiac control centre which sends information to the sympathetic system to the sinoatrial node to increase the heart rate
27
what do chemoreceptors detect and what happens to the heart rate
increase in blood carbon dioxide
heart rate will increase
28
what do baroreceptors detect and what happens to the heart rate
increase in blood pressure
decreases heart rate
29
what do proprioceptors detect and what happens to the heart rate
increase in muscle movement
increases the heart rate
30
what type of hormone is adrenaline
a stress hormone
31
what releases adrenaline
the sympathetic nerves and cardiac nerve
32
what does adrenaline stimulate
the sinoatrial node
33
what does adrenaline do
increases the speed and force of a contraction increasing the cardiac output causing the volume of blood pumped to the working muscles increase
34
what is the hormone released that's the opposite to adrenaline
acetylcholine
35
what is acetylcholine released by
the parasympathetic nervous system
36
what does acetylcholine do
slows down the heart rate
37
what is stroke volume
the volume of blood pumped out by the hearts ventricles in each contraction
38
what is the average resting stroke volume
70ml
39
what does stroke volume depend on
venous return
elasticity of cardiac fibres
contractility of cardiac tissue
40
what is venous return
the return of blood to the right side of the heart via the vena cava
41
what is ejection fraction
the percentage of blood pumped out by the left ventricle per beat
42
why does the elasticity of cardiac fibres increase stroke volume
the more the cardiac muscles can stretch the greater the force of contraction a greater force of contraction increases the ejection fraction
43
what is the elasticity of the cardiac fibres concerned with
the degree of stretch of the cardiac tissues during the diastole phase
44
what is the diastole phase
when the heart is relaxed
45
how does the contractility of the cardiac tissue effect stroke volume
the greater contractility of cardiac tissue the greater the force of contraction this results in an increase in stroke volume as well as ejection fraction
46
what happens to stroke volume when exercise intensity increases
stroke volume also increases
47
when is this only the case for
40-60% of maximum effort
48
what happens after 40-60% of maximum effort to stroke volume
stroke volume plateaus because the ventricles do not have as much time to fill up with blood so can not pump out as much blood
49
what is heart rate
the number of times the heart beats per minute
50
what is the average resting heart rate
72 beats per minute
51
what does heart rate do with exercise
it increases
52
how do you find the maximum heart rate
220-age
53
when does cardiac hypertrophy occur
regular aerobic training
53
what is an anticipatory rise
hormonal action of adrenaline which causes the SAN to increase in heart rate
53
why does the brain need a constant supply of oxygenated blood and nutrients
to maintain its function
53
what is cardiac hypertrophy
when the heart becomes bigger and stronger due to the thickening of the muscle wall
53
what does CHD stand for
coronary heart disease
53
what is bradycardia
when there is a decrease in resting heart rate to below 60bpm
53
what is similar about everyone's cardiac output at rest
it is the same
53
what happens when bradycardia occurs
oxygen delivery to the muscles improves as there is less oxygen needed for contraction of the heart
53
tell me about HDL
high density lipoproteins transport excess cholesterol in the blood back to the liver where it is broken down these are classed as 'good' cholesterol since they lower the risk of developing heart disease
53
tell me about LDL
low density lipoproteins transport cholesterol in the blood to the tissues and are classed as 'bad' cholesterol since the are linked to increased risk f heart disease
53
what is cardiac output
the volume of blood pumped out the heart by the ventricles per minute
54
what is the cardiac output equation
cardiac output= stroke volume x heart rate
54
when does coronary heart disease occur
when your coronary arteries which supply the heart muscle with oxygenated blood becomes blocked or starts to narrow by gradual build up of fatty deposits
54
what happens to cardiac output during exercise
it increases
54
in relation to strokes what can regular exercise help to do
can help lower your blood pressure and help you to maintain a healthy weight which can reduce your chance of stroke by 27%
54
why does cardiac output increase during exercises
because heart rate and stroke volume also increase
54
what are fatty deposits called
atheroma
54
what is atherosclerosis
when arteries harden and narrow and become clogged up by fatty deposits
54
what does the brain need a constant supply of
oxygenated blood and nutrients
54
where does the pressure from blood come from when it is exerted on a blood vessel wall
from the heart as it pumps blood around the body
54
what can cause atherosclerosis
high blood pressure, high levels of cholesterol, lack of exercise as well as smoking
54
what can regular aerobic exercise do when having a high blood pressure
reduces the risk of heart attack by 20% because it lowers both systolic and diastolic pressures by 5-10mmHg
54
what happens if high blood pressure is left untreated
increases the risk of heart attack, heart failure, kidney disease, stroke or dementia
54
what is high blood pressure
blood pressure is the force exerted by the blood against a blood vessel wall
54
what can reduce blood pressure
regular aerobic exercise can reduce blood pressure
54
how many types of cholesterol are there
2 types
54
what does high blood pressure put strain on
the arteries and heart
54
what are the two types
low density lipoproteins
high density lipoproteins
54
what can regular physical activity do to the two types of cholesterol
it lowers bad LDL cholesterol levels and at the same time it significantly increases good HDL cholesterol levels
54
what are the two main types of stroke
ischaemic and haemorrhagic
54
tell me about an ischaemic stroke
they are the most common form and occur when a blood clot stops the blood supply
54
what can blood supply that is cut off from the brain lead to
brain injury, disability, and sometimes death
54
when does cardiovascular drift occur
it occurs during prolonged exercise in a warm environment despite the exercise intensity staying the same
54
tell me about a haemorrhagic stroke
occur when a weakened blood vessel supplying the brain bursts
54
when does a stroke occur
when the blood supply to part of the brain is cut off causing damage to brain cells so they start to die
54
what is the most common type of stroke
ischaemic
54
what is cardiovascular drift characterised as
the progressive decrease in stroke volume and arterial blood pressure together with a progressive rise in heart rate
54
what happens during cardiovascular drift to plasma volume
plasma volume decreases due to the increased sweating response of the body and this reduces venous return and stroke volume. heart rate then increases to compensate and maintain cardiac output
54
why does heart rate increase when venous return and stroke volume decreases
to maintain cardiac output
54
what are the different types of blood vessels
arteries, veins and capillaries
54
what do vein transport and where to
deoxygenated blood back to the heart
54
explain the structure of a vein
thin elastic tissue, blood is at a low pressure, they have valves and a wider lumen
54
explain what arteries do
transport oxygenated blood around the body
54
explain the structure of an artery
thick and elastic outer walls, they have thick layers of muscle, a small lumen and a smooth inner layer they have the highest pressure
54
what do capillaries do
slow down blood flow as they are only one cell thick
54
what do capillaries allow
exchange of nutrients with the tissues to take place by diffusion
54
what is the pressure in a vein like
low
54
what is the pressure in an artery like
high
54
what is blood pressure
blood pressure is the force exerted by the blood against the blood vessel wall
54
what does blood pressure look like in an equation
blood flow x resistance
54
where is blood pressure measured
brachial artery in the upper arm
55
what does systolic mean
when the ventricles are contracting
56
what does diastolic mean
when the ventricles are relaxing
57
when we exercise the heart contracts with more force why is this important
it is important so that the blood leaves the heart under high pressure in order for the muscles to receive the extra oxygen that they require
58
what is the typical blood pressure reading at rest
120/80 mmHg
59
what does mmHg stand for
millimetres of mercury
60
what are the venous return mechanisms
the skeletal muscle pump
the respiratory pump
pocket valves
thin layer of smooth muscle
gravity
61
what is venous return
the return of blood to the right side of the heart via the vena cava
62
what percentage of the total volume of blood is contained in the veins at rest
70%
63
why is it good that 70% of blood is kept in the veins at rest
it is good because a large amount of blood can be returned to the heart when needed
64
explain the skeletal muscle pump
when muscles contract and relax they change shape
this change in shape means that the muscles press on nearby veins causing a pumping effect and squeeze blood back up towards the heart
65
explain the respiratory pump
when muscles contract and relax during breathing in and breathing out, pressure changes in the thoracic and abdominal cavities
these pressure changes compress the nearby veins and assist blood to return to the heart
66
explain pocket valves
these prevent back flow of blood once the blood has passed thought he valves they close to prevent blood flowing back
67
tell me about the thin layer of muscle in the walls of the veins
they squeeze blood back towards the heart
68
explain gravity as a venous return mechanism
helps blood return to the heart from the upper body
69
what happens when systolic blood pressure increases
there is an increase in venous return this is because the pressure in the blood vessels is higher so the blood travels quicker
70
what happens to venous return when you increase the right atrial pressure
venous return decreases
71
what happens to venous return when you decrease the right atrial pressure
venous return increases
72
how can oxygen be transported
3% dissolves into plasma
97% combines with haemoglobin to form oxyhaemoglobin
73
in the muscle how is oxygen stored
oxygen is stored as myoglobin
74
what happens to oxygen at the tissues
oxygen is released from oxyhaemoglobin due to the lower pressure of oxygen that exists there
75
what is the release of oxygen from oxyhaemoglobin called
oxyhaemoglobin dissociation
76
what does myoglobin do
it stores oxygen in the muscle for the mitochondria until it is used by the muscles
77
what does the oxyhaemoglobin dissociation curve represent
the relationship between oxygen and haemoglobin
78
what does the oxyhaemoglobin dissociation curve help us to understand
how haemoglobin in our blood carries and releases oxygen and haemoglobin
79
what is the Bohr Shift
when an increase in blood carbon dioxide and a decrease in blood pH results in a reduction of the affinity of haemoglobin for oxygen
80
what are the three factors responsible for the increase of oxygen dissociation from haemoglobin
increase in blood temperature
partial pressure of blood carbon dioxide increases
blood pH
81
why does an increase in blood temperature mean there is an increase in the dissociation of oxygen from the haemoglobin
when blood and muscle temperature increases during exercise, oxygen will dissociate more readily
82
why does partial pressure of blood carbon dioxide increase mean there is an increase in the dissociation of oxygen from the haemoglobin
as the level of blood carbon dioxide rises during exercise, oxygen will dissociate quicker from haemoglobin
83
why does blood pH mean there is an increase in the dissociation of oxygen from the haemoglobin
more carbon dioxide will lower the pH in the body a drop in pH will cause oxygen to dissociate from haemoglobin more quickly
84
what does vascular shunt mechanism mean
the redistribution of cardiac output
85
why is redistributing blood important
it is important so that it can get to the areas where it is needed to most
86
why will more blood go to the heart
because the heart muscle needs oxygen to beat faster with more force
87
why will more blood go to the muscles
they need more oxygen for energy and more blood is needed to remove waste products such as carbon dioxide and lactic acid
88
why will more blood go to the skin
because energy is needed to cool the body down
89
why does blood flow to the brain remain constant
as it needs oxygen to maintain its function
90
when we do exercise why should the gut be empty
a full gut would mean blood is being redirected to the stomach instead of the working muscles
this would have a detrimental effect on performance as less oxygen is being made available
91
what is vasodilation
the widening of the blood vessels to increase blood flow into the capillaries
92
what is vasoconstriction
the narrowing of the blood vessels to reduce blood flow into the capillaries
93
what controls blood flow and blood pressure
the vasomotor centre in the medulla oblongata
94
what receptors stimulate the vasomotor centre
chemoreceptors
95
what do pre-capillary sphincters
aid blood redistribution
they are tiny rings of muscle located at the opening of the capillaries
when they contract, blood flow is restricted and when they relax blood flow is increased
96
what is arterio-venous difference
the difference between the oxygen content of the arterial blood arriving at the muscles and the venous blood leaving the muscles
97
what is the arterio-venous difference at rest like and why
it is low as not much oxygen is required at the muscles
98
when in the arterio-venous difference high and why
during exercise more oxygen is needed from the blood for the muscles
99
what does training do to the arterio-venous difference
increases because trained performers can extract a greater amount of oxygen from the blood
100
what does A-V02 diff stand for
arterio-venous difference
101
training results in the body being more efficient what are some adaptations
increase in haemoglobin and red blood cells
increase in number of capillaries around the alveoli and muscle tissues
blood becomes less viscous
an athlete becomes better at removing/buffering lactic acid
an athlete becomes better at redistributing blood
102
how does an increase in haemoglobin and red blood cells help an athlete
more oxygen gets around to the muscles
103
how does an increase in number of capillaries around the alveoli and muscle tissues help an athlete
gaseous exchange, carbon dioxide is removed
104
how does blood becoming less viscous help an athlete
improves the blood flow, more nutrients and waste product are removed
105
when an athlete becomes better at buffering lactic acid how does this help an athlete
reduces fatigue and means they can work at high intensity for longer
106
when an athlete becomes better at redistributing blood how does this help an athlete
blood is directed to areas that need it during exercise (muscles) as there is a greater oxygen delivery
107
explain how a lower heart rate can affect oxygen delivery to muscles during maximal exercise
lower heart rate means a higher stroke volume this means that less oxygen is needed for contractions and a lower heart rate will enable greater oxygen delivery to muscles before fatigue sets in
