Topic 1- Notes Flashcards
(85 cards)
1
Q
What is a risk factor?
A
A feature of an individual’s genetic make-up, lifestyle or environment which increases the probability of an unwanted condition.
e.g. age, heredity, physical/ social environment, lifestyle/ behaviour/ choices.
2
Q
What are cardiovascular diseases?
A
Diseases of the heart and circulation.
3
Q
What is the difference between CVD and CHD?
A
CVD includes all diseases of the heart and circulation including CHD, angina, heart attack, stroke, etc.
4
Q
Why do many animals have a heart and circulation?
A
Mass transport to overcome limitations of diffusion in meeting the requirements of organisms?
5
Q
What is open circulatory system?
A
- Where blood circulates in large open spaces.
- Simple heart pumps blood out into cavities surrounding the animal’s organs.
- Substances can diffuse between the blood and cells.
- When the heart muscle relaxes, blood is drawn from the cavity back into the heart through small, valved, openings along its length.
6
Q
What is a closed circulatory system?
A
- Blood enclosed within tubes/ vessels- increases speed and pressure + more efficient.
- Animals with closed circulatory systems are generally larger and more often active then those with open systems.
7
Q
What is a single circulatory system?
A
e. g. fish
- heart pumps de-ox blood to gills.
- blood flows round body then to heart.
- blood flows through heart once per circuit.
8
Q
What is a double circulatory system?
A
- Blood flows through heart twice.
- heart gives blood ‘boost’, speeding up circulation time therefore allows a high metabolic rate- O2 and food substances required for metabolic processes can be delivered faster to cells.
- lung capillaries one side, systemic (body) capillaries the other side.
9
Q
What is water’s dipole nature?
A
Water s a polar molecule. 2 hydrogens are pushed together (V-shape). H end slightly + and O end -, electrons are more concentrated at that end.
+ attract - = hydrogen bonding
solvent properties: any chemicals dissolve in H2O, but not lipids, they are non-polar (hydrophobic).
hydrophilic = polar (water-loving substances)
Water needs a lot of energy to heat up.
10
Q
what is the order of blood vessels?
A
Arteries - small artery - arteriole - capillary - venule - veins
11
Q
The ARteries
A
Walls withstand pressure = thicker than lumen
- smooth endothelium, smooth muscle and elastic fibres and connective tissue (callogen fibres) (outside).
- carry blood away from heart to body/organs
- oxygenated, except plumonary artery
- high pressure therefore thicker walls
- surging pressure (pulse)
- no valves
12
Q
The capillaries
A
- 1 cell thick (endothelium cells)
- carries blood from arteries to veins
- from ox to deoxygenated (opposite in lungs)
- high pressure - tiny vessels but lots of blood - high at arteriole end and down at venule end.
- no valves
13
Q
the veins
A
- walls, thinner than lumen - thicker than capillaries - same as arteries but smaller - less smooth muscle and connective tissue
- carries blood into the heart
- de-ox blood (except in pulmonary vein)
- low pressure - thinner walls
- pressure is constant
- valves prevent backflow
14
Q
the cardiac cycle - 1 heartbeat
1) Cardiac diastole - relax
A
Blood flows into atria, elastic recoil of atrial walls generates low pressure - draw blood in.
Atrioventricular valves are closed.
As ventricles relax, semilunar valves close
Semilunar - ‘dub’ second sound
15
Q
Atrial systole - contract
A
As atria fill with blood, pressure in atria increase, atrioventricular valves pushed open - blood flows into the relaxing ventricles.
The 2 atria contract, forcing remaining blood out.
16
Q
Ventricular systole - contract
A
After a slight delay, the ventricles contract - increase pressure in ventricles so the atrioventricular valves close - ‘lub’ - (first heart sound).
Blood is forced into the aorta and pulmonary artery.
Semilunar valves are open.
Blood flows into relaxing atrium.
17
Q
What is an ECG?
A
- An electrocardiogram
- Checks for problems with electrical activity of your heart
- Results shown as tracings on paper
- Used to investigate the relationship between the heart structure and function
18
Q
Veins and arteries
a) carotid
b) pulmonary
c) hepatic
d) mesentric
e) renal
f) femeral
A
a) head
b) lungs
c) liver
d) intestines (mesentric artery)
e) kidneys
f) legs
19
Q
What is vasoconstriction & vasodilation?
A
Vasoconstriction: reduction in diameter of arterioles resulting in less blood flow to the surface capillaries.
Vasodilation: The opposite of the above.
20
Q
Describe the 2 types of lipoproteins
A
LDLs: Low-density lipoproteins - transport cholesterol ‘bad’. lots = high blood cholesterol levels. May be deposited in artery walls forming atheromas.
HDLs : high-density lipoproteins - transport more protein and less cholesterol than LDLs. Higher density. ‘good’.They decrease blood cholesterol levels and help remove fatty plaques formed in atheromas.
21
Q
What are macrophages and cholesterol?
A
Macrophage: involved in inflammatory response. They’re specialised cells which in gulf and destroy target cells - part of immune system that form if there’s an infection or damaged/dead cells. Formed if there’s a blood clot during atherosclerosis
cholesterol: made in the liver from saturated fats and from our diets. It’s a short lipid molecule needed for good health but too much is bad It can build up in arteries during atheroscelorosis.
22
Q
What is plague and atheromas?
A
Plaque: produced from calcium salts and fibrous tissue building up causing a hard swelling.
Atheroma: build up of fatty deposits, mainly cholesterol.
23
Q
What is referred pain?
A
Where pain is felt somewhere in the body other than the actual source . e.g. heart attack-may feel pain arms
24
Q
What is angina?
A
Means pain
- e.g. chest pain caused by limited blood getting to heart muscle
- usually felt during exercise when the cardiac muscle is working harder
- thought that anaerobic respiration causes chemical changes, which cause this pain
25
Coronary heart disease?
If fatty plaque that's built up in the coronary arteries ruptures showing callogen, a blood clot will form.
This narrow/block the coronary arteries causing the heart to not get enough O2 from the blood and loss of elasticity.
This cause permanent damage and heart attacks.
it's a consequence of atheroscelosis
26
What is atherosclerosis?
Loss of elasticity.
Fatty deposits can either block an artery directly or increase chances of blood clots (thrombosis) - cells can be permanently damaged if clot isn't removed.
If occurring in coronary arteries can cause hear attack (myocaridal infarction)
Definition: It's a progressive disease of arteries resulting in reduced diameter (due to build up of fatty deposits) and loss of elasticity.
27
What are the steps (stages) of atherosclerosis?
1. Artery wall damaged
2. Inflammatory response
3. Large white blood cells enter wall
4. Cholesterol accumulates
5. Atheroma forms
6. Calcium salts and fibrous tissue accumulate
7. Hard plaque forms
8. Wall elasticity reduced
9. Artery narrows
10. Raising blood pressure
11. Atherosclerosis
28
What is :
a) correlation
b) causation
a) When there are 2 variables that show the same changes - it doesn't mean anything
b) when a change in one variable is caused as a result of another variable changing.
29
The consequences of atherosclerosis:
| a) coronary hear disease? (CHD)
- narrowing of coronary arteries - less O2 gets to heart - may result in chest pain called Angina
- Angina usually experienced during exercise - forced to work anaerobically - not enough O2
- If fatty plaque in arteries ruptures - clot forms
- blocks - slows flow to heart. hearts is ischaemic (without blood)
- heart attack /myocardial infarction
CHD can also cause an irregular heart beat (arrhythmia)
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b) Stoke?
If blood to brain is interrupted - artery blocked.
- can be fatal if brain cells are starved of O2 for long
```
Symptoms :
numbness
dizziness
confusion
slurred speech
blurred/lost vision (often in one eye)
NB: (the right side of the brain controls the left side of the body and vice versa)
```
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c) aneurysms?
- if artery narrows/becomes less flexible blood can build up behind it.
- artery bulges as it fills with blood and an aneurysm forms
- aortic aneurysms are likely to rupture when they get about 6-7cm in diameter.
- If it ruptures it can be fatal
32
```
What do:
a) tachycardia and
b) bradycardia
c) ischaemic
mean?
```
a) high resting heart rate
b) slow resting heart rate
c) without blood
33
What are the cardio-vascular disease (VD) risk factors?
Genetics - men have higher blood pressure
Diet - fatty/cholesterol high food is bad
Age - increases as get older
High blood pressure - increase risk
Smoking - tar build up
Inactivity - increases blood pressure when you do exercise
34
What are cohort studies?
| i) for CVD?
- follow large group. People - see who develops disease and who doesn't
- study is prospective - none have condition at the start
- compare results look at correlation in risk factors - very expensive and take a long time.
i) 1948 - 5209 men and women 30-62 recruited
1971, 5124 children (now adults in 1971) joined
3rd generation recruited in 2002
Every 2 yrs participants provide detailed medical history and undergo physical exams and questionnaires.
Results - high blood pressure, high blood cholesterol, smoking, obesity, diabetes, physical inactivity were all identified as risk factors
35
What are case-control studies?
| i) for CVD?
- group of people with disease (cases) compared with control group, info collected on history& risk factors.- retrospective study.
- control group should be representative of case group.
- Important not to match any variables which cd potentially turn out to be risk factors.
i) The INTERHEART study screened patients with 1st heart attack admitted to 262 hospitals in 52 countries.
- controls were matched by age and gender. concluded that different gender, geographic regions or racial/ethnic groups didn't make much difference
36
What are some features of a good study?
1) a clear aim
2) representative sample
3) valid and reliable results
4) sample size
5) controlling variables
37
What does:
i) valid
ii) reliable
iii) accurate and
iv) precise mean?
Valid: if it measures what it's supposed to
Reliable: if it produces measurements that are repeatable and reproducible
Accurate: refers to closeness of measured value to standard or known value
Precise: refers to closeness of 2 + measurements to each other.
38
Oedema?
What is it?
Tissue fluid?
High blood pressure?
Oedema: fluid building up in tissues and causing swelling.
Oedema is a sign of high blood pressure. Going to capillary blood is under pressure forcing fluid and small molecules out into the intracellular space, forming tissue fluid (interstitial fluid).
Tissue fluid drains into a network of lymph capillaries which return fluid to blood via a lymph vessel which empties into vena cava. If blood pressure rises above normal, more fluid may be forced out of capillaries. Fluid accumulates within tissues causing oedema.
39
Relative energy content of carbohydrates, lipids, proteins and alcohol?
Nutrient Energy available per g/KJ
carbohydrates 16
lipids 37
proteins 17
alcohol 29
40
What are carbohydrates?
```
hydrated carbon
e.g. starch and sugar
Cx (H2)On
monosaccharides, disaccharides, polysaccarides
_______________________________________
sugars are all one off these
joined by codensation reaction
split by hydrolysis reaction
```
41
Why do poly/disaccharides not cause as high increase in blood sugar levels as fast as monosaccharides?
monnosaccharides absorbed rapidly therefore cause increase sharply in blood sugar level
poly - + disaccharides have to be digested into monosaccharides first therefore monosacchardies released more slowly
42
What are polysaccharides and examples?
Polymers made up of more than 2 glycosidic bondss.
3 main typpes:
1) starch
2) cellulose and
3) glycogen
all of these are polymers of glucose molecules.
They are not sweet and aren't easily soluble.
1 and 3 act as energy stores within cells. They're compact - not easily dissolvable in water therefore don't affect cone of water in cytoplasm.
43
Cellulose?
Known as dietary fibre. Non starch polysaccharide. Up to 10,000 glucose molecules joined to form a straight chain with no branches (the glucose molecules have a slightly different structure to those found in starch)
It's indigestible in the human gut. Cellulose has an important function in the movement through the digestive tract.
44
Glycogen?
Used by bacteria, fungi and animals as an energy store - composed of glucose molecules. Numerous side branches - it can be rapidly hydrolysed - easy access to stored energy.
In humans glycogen is stored in the liver and muscles.
45
What are lipids?
Fats and oils - lipids enhance flavour - smoother/creamier. Supply over twice the energy - carbohydrates.
Organic molecule found in every type of cell. Insoluble in water - soluble in organic solvents e.g. ethanol.
Most lipids eaten are triglycerides - used as energy stores in plants and animals.
Forms as an ESTER bond - 3 ester bonds in a triglyceride.
46
What are some types of lipids?
saturated and unsaturated fats.
Cholesterol - short lipid - essential for good health - vital for cell membranes with roles in their organisation functioning.
Steroid sex hormones (progesteron/testosterone/etc) + some growth hormones from cholesterol.
Bile salts, involved in lipid digestion and assimulation are also formed from cholesterol.
Cholesterol made in liver from saturated fats and from our diet.
Phospholipids are similar to triglycerides but one of the fatty acids is replaced by negatively charged phosphate group.
47
How can fats be good for us?
Supply energy.
Source of essential fatty acids that the body need but can't synthesise.
Balance diet.
Fat-soluble vitamins (A,D,E and K) can only be absorbed if our diet includes food containing fat.
e.g. deficiency in linoleic acid (an essential fatty acid) can result in scaly skin , hair loss and slow wound healing.
48
Risk factors for CVDs:
| hypertension: high blood pressure
Source: gender/age/fitness/diet, etc
Critical value: 150//90 mmHg
Biology: Blood press. determined by rate/V at which blood's pumped around body - High blood press means artery wall damage more likely.
Effect: one of most common factors in developing CVD. High blood pressure increases risk of atheroscelorosis
49
Cholesterol
Source: high-fat - lots of LDLs
Critical value: mmolL total serum.cholesterol/7mM serum cholesterol
Biology: LDLs - triglycerides - combine with cholesterol and protein and transport it to body cells. Circulate in blood stream and bind to receptor sites on cell membranes before being taken up by cells where cholesterol's involved in synthesis and maintenance of all membranes. Too many LDLs overload membrane receptors and result in high blood cholesterol levels.
Effect: High blood cholesterol levels - LDLs deposited in artery walls - increase risk of atheromas and increase risk CHD
50
Saturated fats
Source: animal fats from meat and dairy products
Critical value: 1g = 37kJ then 81g = too much!
Biology: increase blood cholesterol level
Effect: increase risk atheromas forming and CVD
51
High BMI/obesity
Source: lack exercise/bad diet (high in saturated fats and sugar)
Critical value: 30
Biology: waist to hip ratio better measure of obesity than BMI. More fat you carry especially around you waist = greater risk of heart failure. Obesity can raise your blood pressure and blood lipid levels which increase risk of CVDs.
Effects: increease risk of CDs
52
Smoking
Source: cigarettes
Biology: CO binds to haemoglobin reducing risk of O2 to cells - increase heart rte.
Nicotine stimulates adrenaline production - arteries constrict - raises blood pressure.
Chemicals damage artery walls causing atherosclerosis.
Effect: increase risk CVD, atheroscelosis, early death, coughs and difficulty breathing.
53
High salt intake
Source: salt and processed food with added salt eg crisps
Critical value: +6g. A little is good. Too much is bad.
Biology: high amount. salt causes kidneys to retain water and higher fluid levels in the blood result in elevated blood press.
Effects: higher blood press. caused by excess fluid due to salt result in higher risks of CVD
54
what happens when salt is ingested?
Salt ingested (processed foods) - water potential of plasma decreases - osmosis increases - blood volume increases - systemic blood pressure increases - CVD risk increases
55
Alcohol
Source: Fermented fruit/grains with yeast/bacteria
Critical value: 2--3 units women/day, 3-4 men
Biology: Small amounts thought to protect against CVD slightly. 20% alcohol drank absorbed in stomach, the rest through intestine wall. One main function of liver is detoxification including removal and destruction of alcohol. Liver cell damage can decrease ability of liver to remove glucose and lipids from blood. Liver converts alcohol to ethanol, 3 carbon carbohydrate.
Effect: Most ethanol produced used in respiration some can end up as V.LD is which increase risk of plaquedeposition. Excess alcohol can lead to tissue damage e.g. to liver, brain and heart. Raises blood pres, contributes to obesity and irregular heartbeat.
56
Inactivity/lack aerobic exercise
Source: moderate and vigorous exercise is good
Critical value: less then 21/2 hrs/week. Bit everyday.
Biology: Moderate exercise can reduce high blood press. Exercise also helps maintain healthy weight and seems to raise HDL levels. Inactivity increases risk of getting diabetes.
Effects: less likely to survive heart attack. Diabetes
57
Stress
Source: work deadlines, fear, exams ...
Biology: adrenaline released causing arteries to constrict which raises blood press
Effect: CVDs overeating, poor diet and higher alcohol consumption
58
Free radicals
Source: Unstable radicals form when an atom has an unpaired electron
Biology: highly reactive and can damage many cell components including enzymes and genetic material. vit C, beta-carotene and Vit E can help prevent against free radicals. They provide H atoms that pair up with the radical's unpaired electron, stabilising it.
Effect: Cellular damage can develop cancer, heart disease and premature aging
59
Diabetes (type 2)
Source: high blood glucose levels due o sugar rich diet
biology Insulin help regulate blood glucose levels. the insulin causes cells to absorb glucose so the blood glucose levels return to normal.
Effect: The body not producing enough insulin/the body cells not responding to it well.
60
Fixed Risk Factors:
a) AGe
b) GEnder
c) Family History
a) 60+ Plague can build up over time.
b) male hormone levels e.g. oestrogen increase HDL levels. Testosterone can increase heart rate. Men 3x more likely to get CVD than younger women.
c) genetic predisposition. e.g. Apolipoprotein gene cluster associated with CHD and alzheimers. Inherited.
61
Reducing the risks of CVD:
| How can lifestyle changes help?
Stopping smoking
Exercise
Decrease alcohol
Reduce stress
Reduce cholesterol and saturated fat intake and cholesterol and salt (processed foods) intake
decrease fibre (helps peristalsis), antioxidants, unsaturated fats (veg, oil fish) sterols and stanols.
62
What are plant sterols and stanols and what do they do?
they're natural e.g. veg oil, nuts, seeds
they're similar cholesterols but minimally absorbed
Plant sterols: reduce absorption of cholesterol and increase uptake of LDLs by the liver
63
Drugs: treatment CVD:
| i) statins
Lower cholesterol level in blood by blocking the enzyme that makes LDL cholesterol.
Side effect is muscle aches
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ii) anticoagulants
| iii) platelet inhibitory drugs
```
ii) e.g. wafarin
prevents clotting
side effect = bleeding
iii) e.g. aspirin and clopidogrel
makes platelets less sticky
Side effects = aspirin can irritate the stomach lining
```
65
```
iv) Diuretics
Antipertensive drugs
v) ACE Inhibitors
vi) Beta blockers
vii) calcium channel blockers
```
iv) increase V of urine. lowers blood V and press.
side effect = dizziness
v) blocks production of angiotension II which normally causes vasoconstriction and increases in blood press.
SE = cough/sore throats
vi) block response of heart to hormones and makes contractions less frequent an powerful. SE = diabetes
vii) blocks Ca2 channels in smooth muscle cells in artery lining therefore reduce vasoconstriction.Latter is essential hypertension (could be caused by: electrical impulses in motor neurones supply vascular smooth muscle)
66
Surgery and Gene therapy
Coronary angioplasty: Balloon opens up any constrictions
Coronary artery bypass: Blood vessel from leg replaces blocked artery
Gene therapy: Gene protein enhancing blood vessel growth - blood pressure decreases.
67
Describe waters dipole nature and other features:
Water is a polar molecule. 2 hydrogens are pushed together (v-shape). H end is slightly positive and O end slightly negative because electrons are more concentrated at that end.
+ & - attract = hydrogen bonding
Solvent properties= many chemicals dissolve in H2O, but not lipids, they are non-polar (hydrophobic).
Water needs a lot of energy to heat up.
68
Describe some features of the arteries:
Walls are thicker than the lumen to withstand pressure.
Walls consist of smooth endothelium, then smooth muscle and elastic fibres and then connective tissue (collagen fibres).
They are oxygenated apart from the pulmonary artery.
They have a surging pressure (pulse)
The elastic tissue can stretch to accommodate blood and recoil behind blood to push it to forward.
69
Describe the capillaries:
One cell thick
From Oxford to de-ox, and the opposite in the lungs
Pressure high at arteriolar end but lower at venule end
No valves
Roughly 10um wide inc. lumen
70
Describe the veins:
Walls thinner than lumen, less smooth muscle and connective tissue than arteries.
Pressure is constant, and has valves to prevent back flow.
71
How is blood prevented from flowing backwards in the veins?
Valves
Skeletal muscles contract
Back flow of blood prevented by closing valves as they fill with blood.
Blood pushed forward by muscle towards heart through open valves.
72
How are blood clots formed?
1. Platelets in contact with damaged artery wall
2. Platelets become sticky (when they come into contact with vessel walls they change from flattened discs to spheres with long thin projections- they stick to the exposed collagen forming temporary platelet plugs).
3. Cascade of chemical changes ( protein thromboplastin released from platelets and damaged tissues)
4. Protein thromboplastin catalysts the conversion from protein prothrombin to the enzyme thrombin, which in turn catalyses the conversion of soluble plasma protein fibrinogen into insoluble protein fibrin.
5. Tangled mesh of fibrin, traps blood cells, forming blood clot.
73
Describe the electrical stages of the cardiac cycle:
1. Electrical impulses from the sinoatrial node (SAN) spread across the atria wall, causing contraction.
2. Impulses pass down to the ventricles via the (AVN) atrioventricular node.
3. Impulses pass down the purine fibres (in between the two ventricles) to the heart apex.
4. The impulses spread up through the ventricle walls causing contraction from the bottom upwards. Blood is squeezed into the arteries.
74
Describe monosaccharides:
(CH2O)n- n is no. of C in molecule.
Single sugar unit. Provide rapid source of energy. Require little or no change before use in respiration. Readily absorbed. Side chains position determines properties and type of sugar molecule.
E.g. Types of heroes sugar molecules.
Alpha glucose (main sugar used by cells in respiration)
Galactose (found mainly in disaccharide lactose, found in milk)
Fructose (sugar which occurs in fruit, honey and some vegetables)
75
When does hydrolysis take place?
Splitting 2 sugar units.
| When carbohydrates are digested into the gut and when carbohydrate stores are broken down to release sugars.
76
Sucrose
Disaccharide formed from glucose and fructose.
| Usual form in which sugar is transported around plants.
77
Maltose
Disaccharide made up of Glucose and Glucose.
Produced when amylase breaks down starch. Found in germinating seeds e.g. Barley as they break down their starch stores to use for food.
78
Lactose
Disaccharide formed from glucose and galactose.
Sugar found in milk.
Lactose intolerance, produce digestive problems. One solution: hydrolyse lactose in milk using enzyme lactase.
79
Sources of starch
Storage compound found in plants, occurs in veg, fruit and cereals. Major source of energy.
80
Features and sources of saturated fats:
Fatty acid chains containing max no. H atoms.
Sources: animal fats from meats and dairy products.
Pack closely together. Solid at room temp- strong intermolecular bonds between triglycerides.
81
Features and sources of unsaturated fats:
Double bonds cause kinks in the hydrocarbon chain- preventing close packing, weakening intermolecular forces- liquids at room temp.
Polyunsaturated fats: veg oil, nuts, fish
Monounsaturated fats: olive oil
'Good' fat
Made solid at room temp by adding H making its saturated. These are hydrogenated or trans fats used in processed food. Trans fats occur in low levels in meat and dairy products.
82
How does the use of the Hardy-Weinberg equation allow scientists to determine whether evolution has occurred?
- Identify changes in the allele frequency over time.
| - If allele frequency stays the same, no evolution/if allele frequency changes, evolution.
83
What is genetic diversity?
The number of alleles in a species.
84
Describe the process by which the scientific community critically evaluates new theories:
-peer review
-checking of evidence to ensure its validity.
communicating theory to scientific community.
85
How does molecular phylogeny help determine similarities and differences between the 3 domains?
- Sequence of bases in (DNA/RNA).
- Sequence of amino acids in (proteins/enzymes).
- Structure od Cell membrane/Cell wall).
- Size of ribosomes.
