AQA biology 5.3 heart disease

Charlotte Hewson
Mind Map by Charlotte Hewson, updated more than 1 year ago
Charlotte Hewson
Created by Charlotte Hewson almost 5 years ago


AS - Level AS Biology (unit 1 - 05. the heart and heart disease) Mind Map on AQA biology 5.3 heart disease, created by Charlotte Hewson on 03/13/2015.

Resource summary

AQA biology 5.3 heart disease
1 Atheroma
1.1 start as fatty streaks of white blood cells that take up LDL's
1.1.1 LDL = low-density lipoproteins
1.1.2 grows and forms and atheromatous plaque made up of cholesterol, fibres and dead muscle cells bulges into lumen of artery this narrows the artery this reduces the blood flow this increases risk of aneurysm and thrombosis
2 thrombosis
2.1 when an atheroma breaks through the lining of a blood vessel.
2.1.1 this rough surface interrupts smooth blood flow this leads to formation of a thrombus (blood clot) this thrombus may block blood vessels this reduces/prevents blood flow to tissues beyond tissue deprived of blood often dies this is due to lack of oxygen and glucose and other nutrients. sometimes, they are carried by the blood and become lodged in another artery
3 aneurysm
3.1 form because atheromas weaken artery walls.
3.1.1 weakened points swell to for a balloon-like structure these are filled with blood this is the aneurysm they frequently burst this causes a haemorrhage this causes a loss of blood to the region of body served my that artery a brain aneurysm is known as a cerebrovascular accident (CVA) better known as a stroke
4 myocardial infarction
4.1 commonly known as a heart attack
4.1.1 reduced supply of oxygen to the heart muscle result of blockage in coronary arteries blockage close to junction of aorta and coronary artery will stop the heart because blood supply will be completely cut off blockage further down coronary artery, symptoms are milder because a smaller area of the muscle will suffer oxygen deprivation
5 risk factors
5.1 smoking
5.1.1 carbon monoxide combines easily to haemoglobin forms carboxyhaemoglobin reduces oxygen-carrying capacity of haemoglobin to supply sufficient oxygen to tissues, the heart has to work harder this leads to raised blood pressure this increases risk of CHD and strokes. can also cause insufficient supply of oxygen to heart during exercise this leads to chest pain and in severe cases, a myocardial infarction chest pain is know as angina
5.1.2 nicotine stimulates production of adrenaline this increases heart rate and raises blood pressure this increases risk of CHD makes red blood cells 'sticky' makes them coagulate higher risk of thrombosis, hence strokes or myocardial infarction
5.2 high blood pressure
5.2.1 can be due to genes
5.2.2 there are lifestyle factors prolonged stress certain diets lack of exercise
5.2.3 high pressure in arteries makes them more likely to develop an aneurysm and burst
5.2.4 to resist higher pressure, artery walls thicken and harden, restricting blood flow
5.3 blood cholesteral
5.3.1 high-density lipoproteins remove cholesteral and transport it to liver for excretion help protect arteries from heart disease
5.3.2 low-density lipoproteins transport cholesterol from liver to tissue this infiltrates and builds up in artery walls this leads to the development of atheromas
5.4 Diet
5.4.1 high levels of salt raises blood pressure
5.4.2 high levels of saturated fat increase LDL's this increases blood cholesterol concentration
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