Atherosclerosis and Arterial Disease Flashcards
What are the two divisions of the ANS
Sympathetic and Parasympathetic
Which nerve is responsible for decreasing heart rate
Vagus nerve
Which nerves are responsible for increasing heart rate
sympathetic cardiac nerves
Where is the cardio-respiratory control centre located (brain)
medulla oblongata
Where do the sympathetic nerve fibres originate
originate in the reticular formation of the brain stem and innervate the SA & AV nodes and myocardium.
Where does the vagus nerve originate from?
vagal nucleus of the medulla
Define tonic activity (of sympathetic nerve fibres)
tonic contraction in this case is a constant level of activation from both branches of the ANS
What does blood vessel tone dictate
the ability to vasoconstrict and vasodilate blood vessels
What neurotransmitters are present in sympathetic neurons
Norepinephrine- epinephrine and dopamine aka noradrenaline and adrenaline
Which cells help control blood flow to all vessels via the release of vasodilators (e.g., nitric oxide) and constricting factors.
endothelial cells
How can haemodynamic/ANS function be assessed?
An orthostatic challenge wherein the assessment of central and peripheral blood pressures can provide a valid and reliable clinical indication of cardiovascular health
True or false: Heart disease is currently the leading cause of death in developed countries.
True
What (simply) is heart disease caused by?
impaired coronary blood flow i.e. caused by things such as atherosclerosis
why is a measurement of our blood pressure important?
gives a valid and reliable clinical indication of cardiovascular health can predict future cardiovascular disease
Why is earlier detection of non-communicable disease good
-prevent the illness -can continue to work etc -improves financial economy -improves mental health
define atheroscelrosis
Chronic inflammatory condition affecting large- and medium sized vessels (e.g., aorta, coronary arteries, and large vessels supplying the brain) Characterised by ‘hardening’ of the arteries due to the formation of fibrofatty legions in the intimal lining.
State 3 risk factors for atherosclerosis
ØAge (Men: ≥45 y; Women: ≥55 y or premature menopause without oestrogen replacement therapy)
ØFamily history of premature CHD (MI or sudden death before 55 y in male first-degree relative, or before 65 y in female first-degree relative)
ØCurrent cigarette smoking
ØHypertension (≥140/90 mmHg [confirmed on several occasions] or on antihypertensive medication)
ØLow HDL cholesterol (<40mg/dL)
ØDiabetes Mellitus
ØHigh HDL cholesterol (≥ 60mg/dL)
State the basic pathophysiology process of atherosclerosis
- Endothelial Dysfunction (Injury) à Increased permeability & leucocyte adhesion, with monocyte emigration and platelet adhesion.
- Smooth muscle cell migration from media to intima
- Lipid accumulation in intima, and macrophage engulfment of lipids à Foam Cells
- Smooth muscle proliferation, and deposition of collagen & other extracellular matrix
- Development of fibrous plaque with lipid core
State 4 causes of Endothelial dysfunction?
ØNormal microvascular wear and tear
ØFibrinogen
ØFree radicals
ØTurbulent flow
ØViral attack
ØCarbon monoxide
ØSmoking
ØHyperlipidaemia
ØHypertension
ØInsulin Resistance
ØDiabetes Mellitus
ØAgeing
suggest 3 likely causes of atherosclerosis
- obesity
- poor diet
- smoking
- excess alchohol
- genetic predisposition
- reduced physical activity
- pollutants (i.e. air)
Examples of diseases related to disease of the coronary arteries
- Angina,
- myocardial infarction (MI),
- dysrhythmias,
- conduction defects,
- heart failure
- sudden death.
What are the two types of atherosclerotic lesions:
–Stable Plaque
Obstructs blood flow; associated with chronic ischaemic heart disease (e.g., stable angina)
–Unstable Plaque
Can rupture causing platelet adhesion and thrombus formation; associated with unstable angina and MI.
What are the three acute coronary syndromes
(1) Unstable Angina,
(2) Non-ST segment elevation MI
(3) ST segment elevation MI
describe briefly unstable angina:
–Characterised by symptoms (usually prolonged: >20 minutes) at rest
–No serum markers for myocardial damage
describe briefly non-ST segment elevation MI:
–Characterised by symptoms (usually prolonged: >20 minutes) at rest
–Serum markers for myocardial damage present – indicating severe ischaemia and damage to the myocardial tissues
Describe briefly ST segment elevation MI:
–Acute MI (heart attack) characterised by ischaemic death of myocardial tissue.
–Serum markers detectable
–Area of infarct = vessel affected:
- •30-40 % Right Coronary Artery
- •40-50 % Left Anterior Descending Artery
- •15-20 % Left Circumflex Artery
–Sudden death from Acute MI à death occurs within 1h symptom onset
–Usually attributed to fatal dysrhythmias (ventricular fibrillation)
–Early hospitalisation greatly improves chances of survival
Define chronic ischaemic heart disease
Inability of the coronary arteries to supply blood to meet the metabolic demands of the heart.
What are the three classifications of chronic ischaemic heart disease
–Chronic Stable Angina is associated with a fixed atherosclerotic obstruction and pain that is precipitated by increased work demands on the heart but which is relieved by rest.
–Variant Angina results from spasms of the coronary arteries or other dysfunctions.
–Silent Myocardial Ischaemia occurs without symptoms.
What does the following definition refer to?
‘Involves vessels occlusions or rupture leading to focal or localised brain damage, or global hypoxia-ischaemia that causes widespread brain injury’
Cerebrovascular Disease
the carotid artery supplies which arteries of the brain initially
anterior and middle cerebral arteries
where is the most common site for a thrombosis in the brain
the middle cerebral artery
what are the three types of stroke
- thrombotic
- embolic
- haemorrhagic
describe a thrombotic stroke
blood clot (thrombus) blocks an artery in the area of the brain where it is formed
describe an embolic stroke
a plaque/clot breaks off and blocks an artery elsewhere in the brain to where it formed
describe a haemorrhagic stroke
aneurysm due to increase BP in the meniges or cerebrum of the brain
outline some common symptoms of a stroke
- weakness/paralysis
- decreased sensation
- aphasia
- dysphasia
- dysphagia
- Sight problems
define the ischaemic core
an area of severe ischemia (blood flow below 10% to 25%), the loss of oxygen and glucose results in rapid depletion of energy stores.
define an ischaemic penumbra
he area surrounding an ischemic event such as thrombotic or embolic stroke. Immediately following the event, blood flow and therefore oxygen transport is reduced locally, leading to hypoxia of the cells nearby
Define TIA
transient ischaemic attack
is an ischaemic brain attack with focal cerebral or retinal symptoms that last <24 h, usually <1 h
True or False:
Approximately 40% of all strokes are heralded by a TIA
False
15% of strokes are
Meta-analyses have demonstrated the short-term risk of stroke after TIA to be between 3-10% at 2 days, and 9-17% at 90 days
Outline peripheral arterial disease
PAD refers to an obstruction of the large arteries that supply the body’s periphery
Causes acute or chronic ischaemia
What are 2 risk factors for PAD
ØAge (men aged 60+ y)
ØSmoking
ØDiabetes Mellitus
3 symptoms of PAD
- Pain and cramping with walking (particularly calf pain)
- Tingling / aching / numbness in legs or feet
- Atrophic changes (thinning skin & subcutaneous fat)
- Cool foot
- Popliteal pulse weak or absent
- Blanched limb colour when leg elevated à gravitational effects on perfusion pressure
- Ischaemic pain at rest
- Ulceration
- Gangrene development
What are the three factors you can medically measure to detect atherosclerosis (and how)
- endothelial dysfunction (flow mediated dilation- ultrasound)
- vascular stiffness (pulse wave velocity analysis)
- vessel morphology (CT/MRI)
How can exercise help to reduce the liklihood of stroke/atherosclerosis
- reduces BP,
- improve blood lipid profile (increases HDL cholesterol)
- improves aerobic fitness, both in the acute and long-term
- improves coronary artery endothelial function
- reduces risk of other diseases i.e. T2 diabetes
- Improves BMI/weight
