Cardiovascular Pathophysiology Flashcards
(175 cards)
1
Q
Define pathophysiology
A
Deranged function in an individual or organ that is due to disease.
2
Q
What is a pathophysiological alteration?
A
A change in function as distinguished from a structural defect.
3
Q
What is aetiology?
A
The study of causes. Deals with the origin of disease, the factors which produce or predispose towards a certain disease or disorder.
4
Q
What is epidemiology?
A
The study of population in order to determine the frequency and distribution of disease and measure of risks.
5
Q
What is histopathology?
A
The study of microscopic anatomical changes found in diseased tissue.
6
Q
What is cytopathology?
A
The study of disease changes within individual cells or cell types.
7
Q
What is the no.1 disease of death globally?
A
Cardiovascular diseases
8
Q
What factors is cardiovascular function based on?
A
- Cardiac pumping ability
- Integrity of vasculature
- Blood volume/ composition
9
Q
What factors of cardiac pumping ability affect cardiovascular function?
A
- Pace making electrical signal.
- Force of contraction.
- Muscle strength.
10
Q
What factors of integrity of vasculature affect cardiovascular function?
A
- Presence of blockage.
- Muscle tone/ structural integrity.
- Pressure drop needed to move blood to and through capillary beds.
11
Q
What factors of blood volume/composition affect cardiovascular function?
A
- Water and electrolyte balances.
- Lipid composition
12
Q
What are the 3 layers of the blood vessels?
A
Tunica intima, tunica media, tunica externa/adventitia.
13
Q
What is the tunica intima in terms of blood vessels?
A
Endothelium, basement membrane and internal elastic lamina.
Innermost layer - lines lumen and is the only layer in contact with the blood.
14
Q
What is the tunica media in terms of blood vessels?
A
Middle layer. Elastic fibres and smooth muscle is orientated around the lumen. This layer can stretch and in some circumstance it contract.
15
Q
What is the tunica external/ adventitia in terms of blood vessels?
A
The outermost layer is composed of elastic tissue and collagen.
16
Q
Describe the blood vessel structure of the aorta? What are the benefits of this?
A
The aorta has a lot of elastic tissue in the Tunica Media. This allows stretch of the wall to allow the pulse to pass by.
17
Q
Describe the blood vessel structure in veins. and why this is beneficial.
A
Thin Tunica Media with a lot of collagen and elastic fibres. The Tunica Adventitia is wide with longitudinal smooth muscle to aid retuning blood to the heart.
Wide lumen carries blood at a low pressure
18
Q
Describe the blood vessel structure in arteries and why this is beneficial.
A
They have a narrow lumen and strong walls to carry blood away from. the heart at high pressure.
19
Q
Describe the blood vessel structure of capillaries.
A
Only 1 layer of cells in the endothelium and basement membrane.
Huge surface area for fast exchange.
20
Q
What parts of the body promote venous return ?
A
Legs and diaphragm
21
Q
What is hypertension?
A
High blood pressure
22
Q
What is meant by a ‘primary’ pre-disposing factor to hypertension?
A
No clear known cause
23
Q
What is meant by a ‘secondary’ pre-disposing factor to hypertension?
A
Hypertension as a result of another condition.
24
Q
What blood pressure classes as hypertension?
A
A blood pressure greater than 140 over 90 mmHg.
25
What factors control blood pressure?
- Blood volume
- Effectiveness of heart as a pump for cardiac output
- Resistance of vasculature to blood flow
- Distribution of blood between arteries and veins
26
How is blood volume controlled?
Via fluid loss and fluid intake - regulated in the kidneys.
27
What controls the resistance of vasculature to blood flow?
Controlled via contraction and relaxation of smooth muscle in arteriole walls.
28
What controls the distribution of blood between arteries and veins?
Controlled via relaxation of smooth muscle in vein walls
29
What non-modifiable factors risk factors that affect high blood pressure?
Age
Gender
Genetics
30
What are the modifiable risk factors of high blood pressure?
High sodium intake
Excessive alcohol
Obesity
Stress
31
What is Atherosclerosis?
Patchy deposits of fatty material (atheroma's) develop in the wall of medium and large arteries.
32
How quickly does atherosclerosis develop?
Slowly progressive and cumulative - over years and decades.
33
What is the net result of atherosclerosis?
Loss of elasticity, hardening and thickening of vessel walls and narrowing of the vessels lumen.
34
What are the non-modifiable risk factors of atherosclerosis?
Age
Gender
Genetics
35
What are the modifiable risk factors of atherosclerosis?
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Hyperlipidaemia
Hypertension
Smoking
Diabetes
Some infections such as herpes.
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36
What is hyperlipidaemia?
Excessive levels of lipids in the blood.
37
Outline the steps of atherosclerosis
1. Endothelial lesion initiates the process.
2. Endothelial dysfunction. Leukocytes and changes to vessel permeability.
3. Smooth muscle cells migrate in
4. Accumulation of lipid in fatty streak
38
How does Atherosclerosis affect blood vessel function?
- Atheroma's build up on the vessel walls and cause them to weaken. This can trigger aneurysms.
- Plaque ruptures and promotes clotting - thrombosis or embolism.
- Plaque grows and blocks the artery - stenosis.
39
What is stenosis?
When a plaque grows and blocks the arteries.
40
How is the severity of atherosclerosis defined?
From no obstruction to total obstruction where no blood can move through the vessel at all.
41
What are the 2 main treatments of atherosclerosis ?
Angioplasty
| Stenting
42
What is an angioplasty?
Insertion of a small balloon into the affected blood vessel to inflate it and squeeze out the plaque to re-open the lumen.
43
What is stenting?
A mechanism used to hold blood vessels open.
44
What is an aneurysm?
A blood filled dilation of a blood vessel.
45
What blood vessels are aneurysms most common in?
The aorta and the circle of willis
46
What is the purpose of the circle of willis?
Used to maintain a constant blood supply to areas of the brain.
47
Why do aneurysms happen in the aorta?
Blood vessels where the pressure is highest. Most force acting outwards on the vessel wall
48
Why do aneurysms happen in the circle of willis?
It is a complex structure with a lot of junctions. These junction points are weak in vessel walls and are susceptible to aneurysms.
49
What part of an aneurysm causes damage?
Bursting of the aneurysm
50
How does bursting of the aneurysm cause damage?
It causes a drop in blood pressure and reduced tissue perfusion. If severe, it may cause death.
51
Why does hypertension promote aneurysms?
Hypertension promotes aneurysms because the high blood pressure and atherosclerosis weakens the vessel walls and makes them more susceptible to aneurysms.
52
What is blood stasis?
The blood is not flowing or circulating as optimally as it could to all parts of the body.
53
What factors accelerate aneurysms forming?
Local haemodynamic factors, intrinsic factors, systemic hypertension accelerate development.
54
What is LaPlace's Law? And how does this explain aneurysms?
Arterial wall tension proportional to pressure times radius of arterial conduit. Therefore a positive feedback loop - as diameter increases, wall tension increases, which promotes further diameter increase. This continues until an aneurysm ruptures.
55
What is a vaso vasorum?
Aneurysm causes ischaemia of vessel wall which leads to further expansion and therefore further damage.
56
What is ischaemia?
Blood flow is restricted to a part of the body.
57
What does Virchow's Triad explain?
The way in which blood clots may form in the blood.
58
What is Virchow's triangle and what does it include?
It describes the way that blood clots form in the blood
- Vessel wall injury/ changes.
- Changes in blood flow
- Change in blood constituents
59
What are embolisms?
Moving blockages of the vasculature
60
Name some different types of embolisms?
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Thromboembolisms.
Fat embolisms.
Air embolisms.
Gas embolisms.
Septic embolisms.
Tissue embolisms.
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61
Name some possible consequences of thrombus/embolus formation.
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Stroke
Myocardial infarction
Pulmonary embolism
Deep vein thrombosis
Ischaemic limb
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62
If a thrombus forms in the veins, where is it likely to cause an embolism?
The thrombus is likely to move through the right side of the heart an cause pulmonary embolism.
63
What will happen if a thrombus forms in the veins and a patient also has septal defects ?
The thrombosis formed in the veins may travel to the left side of the heart and therefore travel anywhere in the body. This is called a paradoxical embolism.
64
What is a paradoxical embolism?
If a person forms an embolism in their veins and this therefore travels through the right side of the heart. However, the person has a septal defect and the thrombosis can move to the left side of the heart and therefore travel anywhere in the body.
65
If a thrombus forms in the left atrium, where can this travel?
Anywhere in the body.
66
What is myocardial infarction?
A heart attack
67
What causes a myocardial infarction?
When blood supply to the heart is blocked.
68
What are the risk factors of myocardial infarction?
Atherosclerotic coronary artery disease, angina, previous MI, stroke, smoking, alcohol, diabetes, high BP, high LDLs.
69
Where is referred pain I?
Chest pain radiating to the left arm caused by a heart attack.
70
What type of accident is a stroke?
Cerebrovascular
71
What is a stroke in medical terms?
An interruption of blood supply to some/all of the brain (ischaemia).
72
What are the effects of a stroke?
Neuronal function reduced, neuronal death, heterogenous symptoms.
73
What are the heterogenous symptoms of a stroke?
Damage to different brain regions caused by similar problems.
74
In what way are strokes categorised?
Into whether they are caused by an aneurysm or thrombosis/embolism.
75
What is an ischaemic cerebrovascular account?
The blockage stops the blood supply to an area of brain leading to ischaemia and eventually tissue necrosis.
76
What is a haemorrhage cerebrovascular accident?
The rupture of a blood vessel leads to the compression of blood tissues from expanding haemotoma. This reduces supply to the tissues and leads to ischaemia.
77
What are haemotomas?
Pooling of blood and collection of blood outside the vessels.
78
Why are the veins of the legs particularly affected in terms of vascular problems?
The veins in the legs are particularly affected because when a person is standing, blood must flow upward from the leg veins, against gravity, to reach the heart.
79
What causes deep vein thrombosis?
Poor blood flow leading to formation of blood clots known as thrombi in the deep veins.
80
What are varicose veins?
Abnormally enlarged superficial veins in the legs.
81
What are the 3 layers of the heart wall?
Epicardium
Myocardium
Endocardium
82
Describe the epicardium of the heart and its purpose.
Thin protective layer, as part of the pericardium helps prevent friction, confines position.
83
Describe the myocardium of the heart and its purpose.
Thickest layer, composed of cardiac muscle cells, contractile layer of the heart, contains coronary arteries.
84
Describe the endocardium of the heart and its purpose.
Lines the chambers of the heart and regulates myocardial function.
85
What are the thinner layers of the heart wall?
The epicardium and endocardium.
86
Is the thickness of the myocardium the same across the heart?
No it varies and is thicker in the atria than the ventricles.
87
What is pericarditis?
Inflammation of the pericardium.
88
What causes inflammation of the pericardium during pericarditis?
- Neoplastic syndrome (tumour)
- Autoimmune conditions
- Viruses
- Bacteria
- Uraemia
- Drugs
89
What factors can vary with the cause of pericarditis and also classify the pericarditis?
Histopathological changes
90
What is used to diagnose pericarditis?
ECG
Chest X-ray
Echocardiogram
Ultrasound
91
How does pericarditis alter cardiac function?
- Inflammation of the pericardium causes friction during contraction.
- Chest pain and scratch rubbing sound during cardiac contraction.
- Increases effort required by heart.
92
What are the symptoms of pericarditis?
Shortness of breath
Coughing
Fatigue
93
What causes the coughing in pericarditis?
Coughing is caused by venous hypertension where less blood passes through the heart and so accumulates in the lungs. This causes pulmonary oedema.
94
What is pulmonary oedema?
Fluid within the lungs.
95
What are disorders of the endocardium called?
Endocarditis
96
Describe the onset of endocarditis?
Insidious onset - weeks/months.
97
Why are some of the symptoms of endocarditis similar to heart failure?
Similar because endocarditis reduces cardiac output.
98
What are the symptoms of endocarditis?
Malaise, anorexia, fatigue, flu-like symptoms, low grade fever, night sweats, headache, backache, new heart murmur.
99
What are the specific symptoms of endocarditis that wouldn't occur with heart failure?
Embolisation
Stroke
Abdominal pain
100
What is infective endocarditis?
Microbial colonisation of the endocardium.
101
What effects does infective endocarditis have on the heart?
Causes structural abnormalities with the heart leading to fast, turbulent blood flow, this causes fibrin/platelet/thrombi forming and dissolving.
102
What types of staining are used to identify infective carditis and why?
- H&E staining - used to pick up the tissue.
| - Gram staining - used to identify the bacteria.
103
What is the purpose of the AV valves?
Connect the atrium to the ventricles and prevent back flow during ventricular systole. (bicuspid and tricuspid valves)
104
What is the purpose of the semilunar valves?
Aortic valve separates the left ventricle and aorta. This prevents back flow during ventricular systole. And causes one way blood flow from the atria to the ventricles. (Aortic and pulmonic valves).
105
What is mitral stenosis and how does it affect cardiac output?
The mitral valve opening is narrowed and blood flow from the left atrium to the left ventricle during diastole is reduced. This causes a reduction in cardiac output because less blood can be moves into the ventricle and therefore less can be pumped out of the heart.
106
What is mitral regurgitation and how does it affect cardiac output?
The metal valve leaks when the left ventricle contracts during systole, and some blood flows backwards into the left atrium. This causes cardiac output to be reduced.
107
What is hypertrophic cardiomyopathy?
An increase in the size of an organ or tissue brought about by enlargement of cells, rather than cellular multiplication.
108
What are the mechanisms of hypertrophic cardiomyopathy?
- Inability to dilate prevents filling.
- Larger mass of tissue of heart receives insufficient blood supply.
- Narrowing may prevent ejection of blood from left ventricle.
109
What is dilated cardiomyopathy?
Cardiac enlargement and reduced contraction of one or both ventricles.
110
What are the consequences of dilated cardiomyopathy?
Can result in heart failure, thromboembolism and arrhythmia.
111
What are the mechanisms of dilated cardiomyopathy?
- Excessive stretching (filament overlap)
- Arrhythmia (ineffective pumping)
- Death of the heart tissue
112
How does dilated cardiomyopathy affect cardiac output ?
Reduced stroke volume causes reduced cardiac output.
113
What effects does dilated cardiomyopathy have?
- Problems associated with back-up of blood, stasis of blood and with blood not reaching down-stream tissues.
114
Describe restrictive cardiomyopathy.
Restricts the heart from stretching and filling with blood. This means that blood flow is reduced and backs up within the circulatory system. This eventually develops into heart failure.
115
What is obliterative cardiomyopathy?
Apices of ventricles becomes thickened and fibrotic thereby decreasing volume of the heart.
116
How do cardiomyopathies affect cardiac output generally?
They reduce contractility of the heart and thereby reduce the ability to pump blood.
117
What are cardiac arrhythmias?
Alterations in heart rate or rhythm.
118
What effects on heart efficiency do cardiac arrhythmias cause and how?
Decreased efficiency of heart's pumping:
- Slight increase in heart rate increases cardiac output
But
- Very rapid heart rate prevents adequate filling during diastole.
- Very slow heart rate reduces output to tissues.
This causes irregular contraction to be inefficient as it interferes with the normal filling/emptying cycle.
119
What might cause cardiac arrhythmias ?
Myocardial infarction - loose bloody supply to regions of the heart tissue, triggering death of the tissue.
120
What is coronary artery disease?
The bloody supply to the heart muscle is partially or completely blocked.
121
What is the most common cause of coronary artery disease?
Atherosclerosis of a coronary artery.
122
What are some symptoms of coronary artery disease?
Spasm of arteries, angina, myocardial infarction.
123
What is chronic heart failure?
A complex clinical syndrome characterised by abnormalities of left ventricle function and neurohormonal regulation which are accompanied by effort intolerance, fluid retention and reduce longevity.
124
What is causing chronic heart failure to become more common?
Ageing population (people live longer but have bad health in their later years), lifestyle factors, improved survival from myocardial infarctions.
125
What factors affect cardiac output?
Preload
Contractility
Afterload
126
What is preload of the heart?
The filing of the heart during diastole
127
What is the frank-staring mechanism?
The filling of the heart during diastole; as the heart wall stretches, it contracts more strongly during diastole.
128
What is contractility of the heart?
Simply the strength of the muscular contraction.
129
What is after load of the heart?
Resistance to the pumping of the blood into the major arteries.
130
What are some of the causes of heart failure?
- Infarction that impairs pumping ability or efficiency of conduction system.
- Valve defects.
- Congenital heart defects
- Coronary artery disease.
- hypertension
131
What are some of the symptoms of heart failure?
- Cyanosis
- Dyspnea
- Congestion of the bronchi.
- Pleural effusion.
- Hepatomegaly
- Scrotal edema
- Oedema of legs
- Elevated jugular venous pressure
- Tachycardia, cardiomegaly, ECG changes
- Splenomegaly
- Decreased urine output
- Ascites
- Oedema of hands
132
What is hepatomegaly?
An enlarged liver causing tenderness to in palpitation.
133
What is cyanosis?
Blueness of the skin due to lack of oxygen blood reaching the peripheral tissues.
134
What causes elevated jugular venous pressure in heart failure?
Less oxygen is passing pack via the heart.
135
What is Dyspnoea?
Blood congestion in the lungs.
136
What is systolic dysfunction and what normally causes this?
The heart does not contract normally. Coronary artery disease normally causes this and can impair large areas of the heart muscle by reducing blood flow to areas of heart muscle.
137
What is diastolic dysfunction and what most commonly causes this?
Inadequately treated high blood pressure is the most common cause. High blood pressure stresses the heart because the heart must pump blood more forcefully than normally to force blood into the arteries.
138
How can a failure of the left side of the heart affect blood distribution? What are the further consequences of this?
Blood will back up in the lungs. This causes pulmonary oedema. Right ventricle may enlarge due to extra work of pumping blood to lungs. This then causes failure of the right side of the heart.
139
How can a failure of the right side of the heart affect blood distribution? What are the further consequences of this?
Blood will back up in the systemic circulation and fluid will also accumulate in the peritoneal cavity.
140
What are the symptoms of left side heart failure?
Congestion of the lungs, shortness of breath on exertion, easy fatiguability.
141
What are the symptoms of right side heart failure?
Congestion of peripheral tissues, peripheral oedema, nocturne, ascites and hepatomegaly.
142
What is nocturia?
Frequent nighttime urination when fluid from legs returned to blood stream.
143
What is ascites?
Fluid accumulation in abdominal cavity.
144
What is hepatomegaly?
Enlargement of liver - painful
145
What can worsen heart failure?
Illness, myocardial infarction, anaemia, hyperthyroidism etc.
146
How does heart failure relate to mitral stenosis?
Heart failure can be a cause or consequence of mitral stenosis.
147
What is medical shock?
Serious, often life-threatening condition where insufficient blood flow reaches the tissues leading to hypoxia.
Inadequate supply of nutrients/ removal of metabolites - hypofusional state. This leads to hypoxia, ischaemia and cardiac arrest.
148
What is a hypofusional state and what can this lead to?
Inadequate supply of nutrients/ removal of metabolites causes a hypofusional state which can lead to hypoxia, ischaemia and cardiac arrest.
149
What are the different causes of medical shock?
- Hypovolaemic shock
- Distributive shock
- Cardiogenic shock
- Obstructive shock
150
What is hypovolaemic shock? And what is it caused by?
Low circulating volume caused by loss of fluid from the circulation. This is caused by burns, dehydration and internal/external bleeding.
151
What is distributive shock and what is this caused by?
Low circulating blood volume - blood vessels dilate, lowering blood pressure, loss of control of blood vessel diameters.
This is caused by reaction to infection (sepsis), allergic (anaphylactic shock) or damage to the spinal cord (neurogenic).
152
What is cariogenic shock and what is this caused by?
Failure of the heart to pump effectively. Blood fails to be moved sufficiently leading to inadequate tissue perfusion.
This is caused by myocardial infarction, arrhythmias, cardiomyopathy and valve problems.
153
What is obstructive shock and what is this caused by?
Block of blood flow causes circulatory arrest. This is caused by thrombosis, embolisms, tension pneumothorax.
154
What are the phases of medical shock?
1. Initial
2. Compensatory
3. Progressive
4. Refractory
155
Describe the initial phase of medical shock.
- Hypofusional state
| Lack of oxygen, failure to make ATP, anaerobic respiration, build-up of lactic and pyruvic acid, metabolic acidosis.
156
Describe the compensatory phase of medical shock.
Negative feedback mechanisms attempt to reverse the condition:
- Hyperventilation occurs to try to clear acidosis, baroreceptors detect hypotension, adrenaline and noradrenaline released, vasoconstriction occurs, positive chronotropic effects increases blood pressure, blood pressure further increases by activation of renin angiotensin system, this leads to kidney water conservation, blood diverted to essential organs.
157
Describe the progressive phase of medical shock.
Compensatory mechanisms start to fail;
- Build-up of sodium and leakage of potassium, acidic causes constriction of arteriolar and precapillary sphincters, blood in capillaries, leakage of blood, increased viscosity, further reduction in perfusions, further damage to organs.
158
Describe the refractory phase of medical shock.
Irreversible condition ; brain damage, cell death, potential fatality
159
What stains are used to examine artery structure in a vessel cross section?
H&E staining
160
List what steps need to be carried out to prepare tissues for staining.
Fixing
Dehydrating
Embedding
Then cut into thin sections sections of only a few cells thick.
161
List conditions that are more likely to occur over time if the predisposing factors of cardiovascular disease are not dealt with.
6) Formation of a mature plaque which usually occurs in the later stages of atherosclerosis, where the damage becomes irreversible. The atherosclerosis aneurysm is also likely to cause aneurysms due to weakened vessels and potential full blocking of the artery which can cause severe symptoms in varying parts of the body such as stroke or ischaemia. It also makes the patient more likely to suffer from angina and potentially MI if the oxygen supply to the heart is impaired.
162
Describe the histopathological changes that would be observable in the atherosclerotic arteries.
Narrowing of vessel lumens due plaque formation, thick fibrous cap, fatty deposits, fatty streaks.
163
Explain why a deep vein thrombosis is likely to result in a pulmonary embolus, rather than, for example, an ischaemic stroke.
3) A deep vein thrombosis is most likely to result in a pulmonary embolus as this would travel through the systemic circulation and into the right side of the heart via the vena cava, travel through the heart and become trapped in small vasculature in the lungs. In order to cause an ischaemic stroke, the clot would have to pass through the pulmonary circulation and block blood flow to the brain.
164
What symptoms would you expect in an individual suffering from a pulmonary embolus?
Shortness of breath, chest pain, feelings of anxiety, dizziness and irregular heartbeat.
165
How could atherosclerosis participate in the production of a thromboembolism? What treatment options could be employed to treat the atherosclerosis?
6) The atheroma’s can rupture and cause a build-up of constituents and the formation of a blood clot as a result of damage to the vessel walls. This can then be dislodged and travel to other parts of the body through the circulation, especially due to hypertension as this can trigger movement of thromboembolisms.
To treat the atherosclerosis, angioplasty or stenting could be used. Angioplasty is the insertion of a small balloon into the affected blood vessel to inflate it and squeeze out the plaque to re-open the lumen. Stenting holds open the blood vessels using mesh. ACE inhibitors, beta blockers, statins.
166
Explain the pathophysiological process by which a patient with heart failure may be caused to have swollen ankles.
i. Peripheral oedema - If you have failure of the right side of the heart, the CO of the heart will be reduced and so the ability to pump blood back to the heart effectively will reduce. The blood backed up in the legs and systemic circulation will cause oedema.
167
Explain the pathophysiological process by which a patient with heart failure may be caused to have abdominal pain.
If you have failure of the right side of the heart, the CO of the heart will be reduced and so the ability to pump blood back to the heart effectively will reduce. The blood backed up in the abdominal cavity and may cause pain.
168
Explain the pathophysiological process by which a patient with heart failure may be caused to have distended jugular veins.
Elevated jugular pressure because less oxygen is passing back via the heart.
169
Describe what is meant by a mitral stenosis. Explain its effect upon cardiac output.
3) Mitral stenosis is when the mitral valve opening is narrows and blood flow from the left atrium to the left ventricle during diastole is reduced. This causes blood to back-up in the lungs leading to pulmonary hypertension. This may also cause pulmonary oedema. The right ventricle may enlarge due to extra work pumping blood to the lungs. This then causes the right side of the heart to fail. If the right side of the heart fails, blood will back up in the systemic circulation and possibly in the peritoneal cavity. Cardiac output is reduced because less blood can be moved into the ventricle and therefore less can be pumped out of the heart.
170
Describe how valve disorders other than mitral stenosis may affect cardiovascular output.
Other heart valve defects include mitral regurgitation where rather than blocking blood flow, the valve becomes leaky. This means that when the left ventricle contracts during systole, some blood flows back into the left atrium. This reduces cardiac output.
- Aortic stenosis
All valve disorders reduce cardiac output.
171
Explain the mechanisms by which support stockings reduce the symptoms of heart failure ?
The support stockings prevent further swelling by pushing blood back into her circulatory system to keep the cardiac output consistent.
172
Explain how problems associated with the left side of the heart may go on to cause problem in the right heart.
If the left side of the heart was to fail this can go on to cause failing of the right side of the heart. Mitral stenosis stops blood flow into the left ventricle causing back up of blood and pulmonary hypertension within the pulmonary vasculature. This causes the right side of the heart to be put under increased pressure and likely causing it to fail.
173
Define preload
How much blood is coming back into the heart during diastole.
174
Define contractility
A measure of the strength of the muscular contraction of the heart
175
Define afterload
Resistance to the pumping of blood into the major arteries.
