Topic 1 Flashcards
Def Causal relationship
a change in one variable brings about a change in another but a strong correlation between 2 variables doesn’t prove a causal link between them.
Characteristics of a Cohort study:
Large groups followed over time to see who develops disease
Prospective; at start nobody has disease
Exposure to suspected risk factors recoreded
Expensive
Time consuming
Characteristics case control studies
group with disease compared to control group of individuals who do not have disease
retrospecitve
Features of a well designed study
- Clear: aim hypothesis or question
- Representative participants to sample of population results applied
- No bias
- Sufficient numbers of people
- Clearly defined symptoms
- Measurements truly reflect what they were trying to measure
- Reliable method
- Other variables associated with disease taken into account
- Timescale suitable to exposure and disease development
- Data provides info on what study set out to measure
CVD risk factors (6)
high BP obesity smoking inactivity genetic inheritance dietary- blood cholesterol
Def blood pressure
measure of hydrostatic force of blood on blood vessel walls.
Highest- arteries
Measured in kilopascal (but in medical practice millimetres of mercury, mmHg).
Factors determining BP (3)
- Contact between blood and walls of blood vessels (peripheral resistance)
- Contraction of smooth muscle = lumen narrower= inc. resistance and inc. bp
- arterioles/ arteries constrict due to: loss of elasticity (age), release of hormones (adrenaline), high salt diet.
Odema def
Building up of fluid in tissues, causing swelling
Causes odema
- Arterial end of capillary: blood under pressure, so fluid and small molecules forced through tiny gaps between the cells of the capillary wall, into the inter cellular space. Forms tissue fluid.
- Cells absorb nutrients and O2 from fluids, and give out waste
- Tissue fluid moves back into capillaries by osmosis.
When BP raised, more fluid forced out into capillaries, which accumulates causing odema
What is 1 calorie
quantity of heat required to raise the temp of 1cm3 of water by 1 degree C
General formula: Carbohydrate
Cx (H2O)n
Monosaccharide def
Single sugar unit- monomer
Dissaccharide def
2 single sugar units combined in condensation reaction
3 Monosaccharides
Glucose
Galactose
Fructose
When is Maltose produced
when amylase breaks down starch (germinating seeds)
3 Dissacharides
Maltose
Sucrose
Lactose
3 Polysaccharides
Starch
Cellulose
Glycogen
Characteristics Polysaccharides
Compact molecules
Low solubility in water
Means they do not diffuse across cell membranes and do not affect concentration of water in the cytoplasm, so do not affect movement of water into or out of cell by osmosis
what are Lipids
fats and oils
organic molecules found in every type of cell
Insoluble in water
soluble in organic solvents e.g. ethanol
Saturated, LDL fats def
contains max number of hydrogen atoms
Long and straight hydrocarbon chain, with no C=C. This means can pack together closely with strong intermolecular bonds between triglycerides.
Solid at room temp
Unsaturated, HDL fat def
Monounsaturated. One C=C in each fatty acid chain.
Polyunsaturated: 2 or more C=C.
Double bonds cause a kink in hydrocarbon chain, which prevent them packing closely together. Inc distance between molecules, weakening intermolecular forces.
Liquid at room temp.
How to make unsaturated fats solid at room temp (saturated)
add hydrogen to double bonds.
“hydorgenated” or “trans-fats”
Processed foods
Is cholesterol a lipid
yes
Cholesterol def
short lipid molecules essential for good health
Vital component of cell membranes with roles in:
cell organisation and functioning
where is cholesterol made and form what
liver
saturated fats eg. eggs, meat, dairy
fat provides us with… (3)
energy
essential fatty acids the body cannot synthesise
fat soluble vitamins: A, D, E, K
BMI calculation:
Body Mass/kg DIVIDED BY (height)2/m2
Waist to hip ratio def
continuous, positive correlation, risk of heart attack
Men not over: 0.85
Women 0.90
Waist to hip ratio calculation
Waist circumference DIVIDED BY hip circumference
Consequences of obesity
increased risk
CHD
High BP
high lipid levels
Type 2 diabetes
what is insulin
hormone related to blood glucose levels produced by pancreas.
Type 2 diabetes due to:
continuous high Blood glucose levels due to frequent consumption of sugar rich foods can reduce sensitivity of cells to insulin
How is cholesterol (insoluble) transported in bloodstream
combines with proteins to form lipoproteins
2 types of lipoproteins
- Low density lipoproteins (LDL)
2. high density lipoproteins (HDL)
Characteristics LDLs
1) . Triglycerides from fats combine with cholesterol + protein to form LDLs
2) . Transport cholesterol to body cells
3) . Circulate in blood stream and bind to receptor sites on cell membranes before being taken up by the cells, where cholesterol is involved in synthesis and maintenance of cell membranes.
4). Excess LDLs overload membrane receptors = high blood cholesterol levels. LDL deposited in artery walls = atheroma
Characteristics: High density Lipoproteins (HDLs)
- Higher percentage of protein, less cholesterol
- Made when triglycerides from fats combine with cholesterol and protein
- Transport cholesterol from body tissues to liver - where its broken down. This lowers blood cholesterol levels and helps remove fatty plaques of atherosclerosis
Effect of Saturated and unsaturated fats on LDL and HDL cholesterol
Unsaturated: Decreases LDL and HDL
Saturated: increases LDL and HDL
Reduces activity of LDL receptors so LDLs not removed from blood
Smoking increases:
Risk of CVD
Affects of smoking on circulatory system: (4)
- reduced O2 supply to cells: carbon monoxide binds to haemoglobin, reducing O2 supply to cells
- Increased BP
Nicotine stimulates production of hormone adrenaline- which increases HR (inc BP) and constricts arteries + arterioles - Atherosclerosis triggered - chemicals cause damage to artery linings
- Linked to reduction in HDL cholesterol levels
Effects of moderate exercise:
Prevent high BP
Raises HDL cholesterol levels (decreased risk type 2 diabetes)
Risk of Heart Attack/ CHD
inactivity high BP high blood cholesterol smoking hereditary obesity
What are aplioproteins?
Protein component of lipoproteins
formed in liver and intestines
Role in stabilising lipoprotein structure and recognising receptors involved in lipoprotein uptake on the plasma membrane of most cells.
Role Aplioprotein A
major protein in HDL
Removal of cholesterol to the liver for excretion
Mutations associated with low HDL levels and reduced removal of cholesterol from blood increases CHD risk
Role Aplioprotein B (APOB)
Main protein: LDL
Molecule transfers cholesterol from blood into cells
Mutations: higher LDL levels, inc CHD
Aplioprotein E
Component HDL and very low density lipoproteins (VLDLS)
Removal of excess cholesterol from blood to the liver
3 common alleles: produces 3 forms of protein: E2, E3, E4.
APOE4 slows removal from blood, increased risk of CHD
What does multifactorial mean
Disease is not caused by one factor alone
How do unstable radicals result
when an atom has unpaired electrons
What are radicals
highly reactive. can damage cell components including enzymes and genetic material- associated with some types of caner, heart disease and premature ageing
What can protect against radical damage
vitamins C, E and beta- carotene. They provide hydrogen atoms which stabilise the radical by pairing with its unpaired electron
What do antioxidants do
stop platelets sticking together
what does a diet high in salt do
kidneys retain water. Higher fluid levels in blood= elevated BP and inc CVD risk
what does stress do
release adrenaline; arterioles and arteries constrict, inc BP
overeating
higher alcohol consumption
what does heavy alcohol consumption do
increased:
BP
Obesity
Irregular HR
Direct tissue damage to liver, brain, heart
functions of the liver (2)
- process fats, proteins, carbs
2. detoxification
what does damage to the liver impair? (2)
Ability to remove from blood:
glucose
lipids
what is moderate drinking associated with
higher HDL levels
6 ways to reduce CVD
stop smoking maintain low LDL cholesterol regular PA moderate/no alcohol maintain resting BP below 140/85 Maintain normal BMI and waist to hip ratio
3 drugs for high BP
ACE inhibitors
Calcium channel blockers
Diurectics
what are ACE inhibitors
antihyperintensive drugs which reduce synthesis of hormone which causes vasoconstriction of blood vessels (angiotensin II).
when is BP medecine required
systolic equal or over 160
diastolic 100
Side effects ACE inhibitors (4)
dry cough
dizziness
abnormal heart rhythm
reduction in kidney function (failure if already have disease)
What are Calcium Channel blockers
antihyperintensive drugs that block the calcium channels in muscle cells which prevents muscle contraction, meaning blood vessels do not contract, lowering BP
Side effects: Calcium channel blockers (6)
headaches dizziness swollen ankles due to build up of fluid in legs abnormal heart rhythm flushing red in face constipation
What do diuretics do
increase volume of urine produced by kidneys, thus ridding body of excess fluids and salt. This decreases blood plasma volume and cardiac output, lowering BP
Diuretics side effects (3)
Dizziness
Nausea
Muscle cramps
Reducing blood cholesterol: (1)
Low fat diet
What is a cholesterol lowering drug
Statins
what do statins do
inhibit an enzyme involved in production of LDL cholesterol by the liver, decreasing risk of: heart attack and stroke
Side effects of Statins (7)
tired disturbed sleep feeling sick vomiting diarrhoea headache muscle weakness
(cancer)
How can diet be altered to reduce CVD (6)
energy balanced reduce saturated fat Reduced cholesterol reduce salt more polyunsaturated fats
more non starch polysaccharides: pectins.
“soluble fibre” lowers cholesterol: fruit, veg, pulses, grain (oats). These are partially digested- leaving a gel which traps cholesterol and prevents its absorption.
why are oily fish good
contain omega 3 fatty acids which are polyunsaturated and essential for cell functioning, linked to reduction in joint inflammation and heart disease.
Why are fruit and veg good
Often non starch polysaccharides
antioxidants
plant sterols reduce LDL cholesterol, which competes with cholesterol absorption in intestine.
What does aspirin reduce (2) and what is it
platelet stickiness
Likelihood of clot formation
platelet inhibitory drug
What is warfin and what does it do
anticoagulant drug
interferes with vitamin K production, thus affecting synthesis of clotting factors
HOWEVER risk of bleeding can be worse than asprin
risks of asprin
bleeding in gastrointestinal tract
what is mass flow
liquid transported in one direction due to difference in pressure
Is the hydrogen end of the dipole water positive or negative
positive
what types of properties does water have
solvent and thermal
what are the solvent properties of water
dipole : chemicals dissolve easily
ionic substances dissolve easily in water (become hydrated) and surrounded by H20 molecules.
Polar molecules dissolves easily in water if hydrophilic (water loving)
Hydrophobic not soluble in water, eg. lipids
How are dissolved substances transported in circulatory system
blood
lymph systems
Plants:
xylem
phloem
Thermal properties of water
high specific heat capacity so large amount of energy to break H bonds
Organisms avoid rapid changes in internal temp
