AS Biology Chapter 1.4 The risks of developing CVDs

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Chapter 1.4 ­ The risk of developing cardiovascular disease
Risk describes the probability that a particular event will happen.
The bigger the sample, the more significant the results are.
Longitudinal studies follow the same group of individuals over many years, so there results are more
meaningful.
When looking at a study, you need to see if it is valid (is it properly designed to answer the questions
being asked). Also to see if the measurements have been carried out with precision. Also consider
whether it is reliable (have other scientists repeated it and gotten similar results). Also check to see
whether it is biased or not.
Factors of CVDs which cannot be altered:-
Genes ­ Genetics can cause arteries to be more damaged, higher tendency to develop
hypertension or the cholesterol problem may be faulty.
Age ­ As you get older, your blood vessels lose their elasticity and begin to narrow.
Gender ­ Men are more likely to suffer from CVDs because women produce oestrogen
which reduces the build-up of plaque.
Smokers are more likely to develop CVDs.
If you are overweight you have a higher risk of developing CVDs. You are more likely to suffer from
high blood pressure, which also increases the risk of CVDs.
Regular exercise slows the heart rate, lowers blood pressure, lowers blood cholesterol levels and
balances the lipoproteins in your blood. All these lower your risk of CVDs.
High levels of stress increase the risk of CVDs, by causing prolonged high blood pressure and a faster
heart rate.
High levels of saturated fats in the diet many be a risk factor, as it shows a correlation. Unsaturated
fats are linked to high blood cholesterol levels. Cholesterol is involved in plaque formation.
Low-density Lipoproteins (LDLs) ­ Formed from saturated fats, cholesterol and protein. If
level of LDLs is high, your cell membranes become saturated and so more LDL cholesterol is
left in your blood.
High-density Lipoproteins (HDLs) ­ Formed from unsaturated fats, cholesterol and protein.
It carries cholesterol to the liver to be broken down.
Elliot and McLachlan developed a theory that proteins in milk cause problems in the heart. There are
two forms, A1 and A2. A2 causes no problems but A1 might be a factor linked to CVDs.
McCully noticed that young children who had atherosclerosis, was linked to problems in
metabolising the amino acid homocysteine, so he came up with a new hypothesis that a problem in
homocysteine metabolism could be part of the cause of CVDs, so increasing vitamin B and folic acid
in the acid allows homocysteine to be metabolised instead of building up in the blood.

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Diuretics ­ Increases volume Beta blockers ­ Blocks the response
of urine produced, getting rid of the heart to hormones such as
of excess fluids and salts. This adrenaline which speed up the heart
reduces the blood volume so rate and blood pressure, so the heart
the blood pressure falls. rate is lower.
Drugs that reduce blood
pressure are
Sympathetic nerve inhibitors ­ antihypertensive.…read more

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