Topic 1: 1.2 Flashcards
Cardiovascular disease
Atheroma formation
The wall of an artery is made up of several layers -> the endothelium is usually smooth and unbroken
1. If he endothelium becomes damaged (endothelial dysfunction) collagen is exposed and and inflammatory response is triggered where white blood cells are attracted to the damaged site
2. White blood cells and lipids collect under endothelium lining
3. Over time, WBCs, lipids and connective tissues build up and harden forming a fibrous plaque/atheroma
4. The atheroma partially blocks the lumen of the artery and restricts blood flow increasing blood pressure
5. The hardening of the arteries caused by atheroma is called atherosclerosis
Cardiovascular disease
Thrombosis: what it is and its consequences
Formation of a blood clot at site of rupture -> triggered by an atheroma rupturing the endothelial wall
Consequences:
- blockage of that artery
- blockage of an artery elsewhere in the body -> this can cause a stroke, heart attack and deep vein thrombosis
- blood flow is restricted to tissues -> less oxygen and glucose reaches tissues so less aerobic respiration
Cardiovascular disease
Blood clot formation
Thrombosis is a preventative mechanism by the body to prevent blood loss when a blood vessel is damaged and a series of reactions take place to form the blood clot (thrombus)
1. A protein called thromboplastin is released from the damaged blood vessel
2. Thromboplastin combines with calcium ions found in the plasma and they trigger the conversion of prothrombin (soluble protein) into thrombin (enzyme)
3. Thrombin catalyses the conversion of fibrinogen (soluble protein) into fibrin (insoluble fibre)
4. Fibrin forms a mesh to trap platelets and red blood cells forming the blood clot
Myocardial infection
Coronary arteries supply the heart muscle with blood that contains oxygen and glucose needed by the heart to carry out aerobic respiration
1. If a coronary artery becomes completely blocked by a blood clot, an area of the heart muscle will be completely cut off from its blood supply so it wont receive any oxygen
2. No oxygen means that cells in the heart muscle can’t carry any aerobic respiration
-> this causes myocardial infection (heart attack) and eventually the death of cells
3. This can lead to death of heart muscle and if a large area of the heart is affected the complete heart failure can occur (often fatal)
Cardiovascular disease risk factors: diets
. Diet high in salt: increases blood pressure -> damages endothelium lining
. Diet high in saturated fats: increases blood cholesterol levels -> increase atheroma formation as it build up forming a plaque and sticks to exposed collagen when endothelium is damaged
Cardiovascular disease risk factors: inactivity
. Heart has to work harder to pump blood around the body to deliver enough oxygen and glucose for aerobic respiration
. Increases blood pressure
Cardiovascular disease risk factors: high blood pressure
Increases risk of damage to endothelium lining -> increases risk of atheroma formation which can lead to CVD
Cardiovascular disease risk factors: smoking
. Carbon monoxide -> haemaglobin combines with carbon dioxide instead of oxygen so less oxygen is carried by the blood
. Nicotine -> makes platelets more sticky increasing the chance of blood clots forming
. Reduces antioxidants in the blood -> these protects cells from damage so less of them means damage to the endothelium is more likely to
Cardiovascular disease inherited risk factors: genetics
People can inherit certain alleles that make them more likely to high blood pressure or high blood cholesterol
Cardiovascular disease inherited risk factors: age
Plaques form over a long period of time which occurs with age
Cardiovascular disease inherited risk factors: gender
Men are 3 times more likely to suffer from CVD than premenstrual women
-> this is because oestrogen increases `good´cholesterol in blood making atheroma less likely to form
Interpreting data on risk factors: analysing data on illness or mortality
Correlation: there’s a link between that factor and that disease
Causation: having that factor will cause the disease
Analysing data:
- describe the data
- draw conclusions
- check if any conclusions are valid (reliability of data)
- comment on conflicting evidence -> evidence that lead to a different conclusion than other studies
Interpreting data on risk factors: evaluating the design of studies -> variables
. Sample size: the larger the number of participants the more reliable the results -> makes results representative
Interpreting data on risk factors: evaluating the design of studies -> variables
The more variables controlled the more reliable the results
Interpreting data on risk factors: evaluating the design of studies -> data collection
The less bias the more reliable the results
Interpreting data on risk factors: evaluating the design of studies -> controls
Presence of controls increase validity of results
Interpreting data on risk factors: evaluating the design of studies -> repetition by other scientists
If other scientists produce the same results then the results are more reliable
Treatment of CVD: antihypertensives -> benefits
. Different types of antihypertensives work in different ways so they can be given in combination to reduce blood pressure
. Blood pressure can be monitored at home so the patient can see the efectivity of the drugs
Treatment of CVD: antihypertensives -> risks
. Side effects of low blood pressure include: palpitations, abnormal heart rhythms, fainting, headaches and drowsiness
. Other side effects include allergic reactions and depression
Treatment of CVD: statins -> benefits
. Reduce the risk of developing CVD as they reduce the amount of `bad´cholesterol produced in the liver
Treatment of CVD: statins -> risks
Side effects include muscle and joint pain, digestive system problems, increased risk of diabetes, nosebleeds, headaches and nausea
Treatment of CVD: anticoagulants -> benefits
. Can be used to treat people who already have blood clots or CVD
. Prevent any existing blood clots from growing larger
. Prevent blood clots from forming
Treatment of CVD: anticoagulants -> risks
. For injured people it can cause excessive bleeding which can leas to fainting or even death
. Other side effects include allergic reactions, osteoporosis and swelling of tissues
. For pregnant women it can cause damage to the fetus
Treatment of CVD: platelet inhibitory drugs -> benefits
Can be used to treat people who already have blood clots for CVD
Treatment of CVD: platelet inhibitory drugs -> risks
Side effects include rashes, diarrhoea, nausea, liver dysfunction and excessive bleeding
