Topic 1 Part 2 Flashcards
Definition of Risk
Probability of the occurrence of an unwanted event or outcome
How so you express risk numerically?
As a decimal, quoting a time period
When do people overestimate risk?
Involuntary, Unnatural, Unfamiliar, Dreaded, Unfair, Very Small, Sudden Danger (rather than long term risk)
What is a null hypothesis?
Hypothesis that a factor will not have an effect
What is a cohort study?
Group of people studied over time to see who develops a disease
What is a case control study?
Group who do have the disease compared to a group who don’t have the disease
Features of a good study
Clear aim, representative sample, valid and reliable results (large enough sample size), all factors accounted for
Major risk factors of CVD
High Blood Pressure Obesity Blood cholesterol/other dietary factors Smoking Genetic Inheritance
Hypertension - what and why is it s problem?
High blood pressure. Increases likelihood of atherosclerosis occurring. Force of blood against walls of blood vessels.
How do you measure blood pressure?
Sphygmomanometer. Measure pressure for blood to spurt when artery is squeezed.
Healthy blood pressure?
Systolic 100 - 140
Diastolic 60 - 90
How is pressure maintained during diastole?
Elastic recoil of arteries
Causes of high blood pressure
Natural loss of elasticity with age, hormones such as adrenaline, high salt diet.
Signs of high blood pressure
Oedema (swelling of tissue), due to increased pressure forcing more fluid out of capillaries into tissue
Dietary energy provisions
Carbohydrates (16 kJ/g)
Lipids (37)
Proteins (17)
Alcohol (29)
Formula of carbohydrate
Cx(H2O)n
What reaction joins monosaccharides?
Condensation reaction
Importance of Glucose
Main sugar used in respiration. Forms starch and glycogen.
Importance of Galactose
Component of lactose.
Importance of Fructose
Naturally occurs in fruit, honey and some vegetables. Attracts animals so helps with seed dispersal.
Name of bond between two sugars
Glycosidic bond
Why forms sucrose?
A glucose and a fructose
What forms maltose?
Two glucose
What forms lactose?
Galactose and glucose
How do you split a glycosidic bond?
Hydrolysis - add water
Differing effect of mono/polysaccharides?
Mono - absorbed quickly, sharp rise in blood sugar level
Poly- has to be digested, no sharp rise, monosaccharides released slowly
3 main polysaccharides?
Starch and cellulose in plants. Glycogen in animals.
2 features of polysaccharides that differ from mono/disaccharides?
Sparingly soluble and do not taste sweet
Benefit of storage as starch/cellulose?
Compact molecules. Low solubility means don’t upset osmotic balance.
What makes up starch?
Amylose and amylopectin
What is amylose?
Straight chain of 200-5000 glucose molecules with 1,4 glycosidic bonds. Coils into spiral shape.
What is amylopectin?
Polymer of glucose with 1,4 bonds and 1,6 bonds which form side branches.
Which starch component is more common?
70-80% amylopectin, 20-30% amylose
Animal storage molecule?
Glycogen. Numerous side beaches mean rapidly hydrolysed, making access to energy easy.
Function of cellulose in the diet?
Dietary fibre - movement through digestive tract.
Solubility of lipids?
Insoluble in water, soluble in organic solvents eg. Ethanol
Most common lipid?
Triglycerides - three fatty acids and one glycerol
What is a saturated fat?
Lipid with max no. Hydrogen atoms. Common in animal fat and dairy products. Solid at room temp.
Unsaturated fats?
Double carbon bonds. Link in chain. Oils that are liquid at room temp.
What is cholesterol?
Short lipid. Vital component of cell membranes. Produces various hormones. Forms bile salts (lipid digestion). Made from sat fats in liver.
What’s a phospholipid?
Similar to triglycerides but phosphate group replaces one fatty acid.
Importance of fat
High in energy, only source of fat soluble vitamins
Why is obesity bad?
Raise blood pressure and elevate blood lipid levels.
Relationship of sat fat and CVD?
Positive correlation - high %age sat fat = increased incidence of CVD
Function of lipoproteins?
Cholesterol is not soluble in water, so to be transported in the blood stream it is combined with proteins to form soluble lipoproteins.
What are the two major transport lipoproteins?
LDLs and HDLs (Low and High Density Lipoproteins)
What’s and LDL?
Main carrier in blood. Formed from triglycerides in sat fat and proteins. Bind to receptors for uptake into cells. Excess LDLs overload receptors resulting in high blood cholesterol levels. This may be deposited in artery walls forming atheromas.
What are HDLs?
Made when triglycerides from unsat fats combine with protein. Transports cholesterol from body tissues to liver where it is broken down. Lowers blood cholesterol level and helps remove fatty plaques of atherosclerosis.
How do unsaturated fats help cholesterol removal?
Mono- help in removal from blood
Poly- increase activity of LDL receptor sites, actively removing LDLs from the blood.
HDL - good or bad?
Good
LDLs - good or bad?
Bad
Saturated fats - good or bad?
Bad
Unsaturated fats- good or bad?
Good
Effect of smoking?
Carbon monoxide binds to haemoglobin. Nicotine stimulates adrenaline production which causes constriction of arteries and raise blood pressure. Numerous chemicals can trigger atherosclerosis. Reduction in HDL levels
Example CHD genes
Apolopoprotein A, B, E
What is a radical?
Atom with an unpaired electron
Problem with radicals?
Highly reactive and cause damage to many cell components
What protects against free radicals?
Vitamin C, beta-carotene, vitamin E
How do vitamins protect against radicals?
Provide hydrogen atoms that stabilise them.
Problem with high salt diet?
Kidneys retain water, higher fluid levels in the blood result in elevated blood pressure.
How is high blood pressure treated?
ACE inhibitors, calcium channel blockers and diuretics.
What so ACE inhibitors do?
Reduce vasoconstriction, lower blood pressure.
Side effects of ACE inhibitors?
Dry cough, dizziness, arrhythmia, reduction in kidney function.
What do calcium channel blockers do?
Block calcium channels in muscle cells lining arteries. Prevents contraction, lowering blood pressure.
Side effects of calcium channel blockers?
Headaches, dizziness, build up of fluid in legs, arrhythmia, flushed face and constipation.
What do you call blood pressure lowering drugs?
Antihypertensives
What is a triglyceride?
An ester derived from glycerol and three fatty acids
What do diuretics do?
Increase urine production, ridding body of excess fluid and salt. Less volume of plasma, lower blood pressure.
Side effects of diuretics?
Dizziness, nausea, muscle cramps
Cholesterol lowering drugs?
Statins. Inhibit enzyme in production of LDL cholesterol
Blood clot prevention?
Platelet inhibitory - reduced stickiness
Anticoagulant - affects synthesis of clotting factors
Problem with clot preventing drugs?
Both are liable to cause internal bleeding in the gastrointestinal tract.
