Basis of the heart disease

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Atheroma

1. Fatty deposit within wall of artery

2. Begins as fatty streaks = accumulations of WBC taken up LDLs

3. Streaks enlarge to form atheromatous plaque (cholesterol/fibres/dead muscle cells)

4. Buldge into lumen of artery - narrow the lumen so blood flow reduced

5. Increase risk of two dangerous conditions:

- thrombosis

- aneurysm 

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Thrombosis

1. Atheroma breaks through endothelium of blood vessle, forms rough surface interupting blood flow

2. Result in clot/thrombus

3. Thrombus blocks blood vessel, blood prevented from tissues beyond

4. Tissue deprived die as lack of oxygen, glucose and other nutrients

5. Thrombus carried from place of origin and blocks another artery

6. Thrombus in coronary artery

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Aneurysm

1. Atheromas forming thrombus weaken artery walls

2. Weak points swell to form aneurysm (blood-filled, balloon-like)

3. Frequently burst, haemorrhage

4. Therefore loss of blood to region of body served by artery

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Myocardial Infarction

1. Heart Attack

2. Reduced supply of oxygen to muscle

3. Blockage in coronary arteries

4. If close to junction of coronary arteries and aorta, heart stop beating as blood supply cut

5. Heart muscle has lack of oxygen

6. Dies

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Risk Factors of CHD

1. Smoking

- Carbon Monoxide:

combines with haemoglobin in RBC to from carboxharmoglobin. Reducing oxygen-carring capacity of blood. To supply enough oxygen, heart works harder. leads to angina.

- Nicotine:

Stimulates production of adrenaline, increasing heart rate and raises BP. Makes platelets more 'sticky' leading to higher risk of thrombosis, hence myocardial infarction

2. High Blood Pressure

- higher pressure in arteries, heart work harder to pump blood into them

- more likely to develop aneurysm and burst

- to resist, wall thicken and harden, restricting flow of blood

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Risk Factors of CHD

3. Blood Cholesterol - types:

- HIGH DENSITY LIPOPROTEINS (HDLs)

remove cholesterol from tissues and transport it to liver for excretion. Help protect arteries.

- LOW DENSITY LIPOPROTEINS (LDLs)

transport cholesterol from liver to tissues, including artery walls, infiltrate leading to development of atheroma and heart disease

4. Diet

- High levels of salt - raise BP

- High levels of saturated fat - increase LDLs and blood cholesterol concentration

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