Topic 1 Flashcards
(114 cards)
1
Q
what is cardiovascular disease?
A
diseases of the heart and circulatory system. main form is coronary heart disease or strokes.
2
Q
what is a closed circulatory system?
A
blood enclosed within vessels.
3
Q
what is an open circulatory system?
A
blood diffuses through body cavities.
4
Q
what is a single circulatory system?
A
blood is pumped straight to where gas exchange takes place and continues to the rest of the body.
5
Q
what is a double circulatory system?
A
blood travels through the heart twice on one complete journey through the body.
6
Q
what three things does a circulatory system need?
A
heart, blood vessels, transport medium.
7
Q
what is the primary purpose of the heart and circulation?
A
to move substances around the body.
8
Q
what is diffusion?
A
the random movement of molecules or ions from a region of their high concentration to a region of their low concentration.
9
Q
what is mass flow?
A
movement down a concentration gradient of a liquid or gas and all the particles it contains due to difference in pressure e.g. blood in the circulatory system.
10
Q
what is a mass transport system?
A
a system that transports a substance in bulk from specialised exchange organs to the body cells and to remove metabolic waste in an organism. large organisms cannot rely on diffusion alone to meet their metabolic requirements as it is too slow so they need a mass transport system to move substances rapidly over long distances e.g. xylem in a flowering plant and the circulatory system in an animal.
11
Q
why is water a polar molecule (also known dipole)?
A
it has an unevenly distributed electrical charge. the two hydrogen atoms are pushed towards each other forming a v-shaped molecule. the hydrogen end of the molecule is slightly positive and the oxygen end is slightly negative because the electrons are more concentrated at that end. this polarity accounts for many of the biologically important properties of water.
12
Q
what type of bonding holds water molecules together?
A
hydrogen bonding as the slightly positively charged end of a water molecule is attracted to the slightly negative ends of surrounding water molecules. this results in water being liquid at room temperature.
13
Q
what is cohesion?
A
the attraction between molecules of the same type e.g. two water molecules.
14
Q
why is water cohesive and how is that useful?
A
water molecules are very cohesive because they are dipolar. this helps water to flow making it great for transporting substances.
15
Q
why is it important that water is a solvent?
A
many chemicals dissolve easily in water due to their dipole nature allowing vital biochemical reactions to occur in the cytoplasm of cells. free to move around in the aqueous environment the chemicals can react, often with water itself being involved in the reaction (hydrolysis and condensation reactions). the dissolved substances can also be transported around organisms in animals via the blood and in plants through the xylem and phloem.
16
Q
what are the properties of polar molecules?
A
can dissolve easily in water. their polar groups become surrounded by water and go into solution. they are said to be hydrophilic.
17
Q
what are the properties of non-polar substances?
A
do not dissolve in water so are said to be hydrophobic e.g. lipids. to enable transport in blood, lipids combine with proteins to form lipoproteins.
18
Q
how is water a good solvent?
A
as water is dipolar, the slightly positive end of a water molecule will be attracted to the negative ion and the slightly negative end of a water molecule will be attracted to the positive ion. the ions will get surrounded by water molecules, they will dissolve.
19
Q
what is specific heat capacity?
A
the amount of energy in joules required to raise the temperature of 1cm3 of a substance by 1 degrees.
20
Q
what are the thermal properties of water?
A
the specific heat capacity of water is very high because a large amount of energy is required to break the hydrogen bonds. a large input of energy causes only a small increase in temperature, so water warms up and cools down slowly.
21
Q
how are the thermal properties of water useful?
A
it helps organisms to avoid rapid changes in their internal body temperature and enables them to maintain a steady temperature even when the temperature in their surroundings varies considerably. this also means that bodies of water in which aquatic animals live do not change temperature rapdily.
22
Q
what are the properties and function of the left ventricle of the heart?
A
thicker as have more muscular walls than the right ventricle because it needs to contract powerfully to pump blood all the way round the body. the right ventricle only needs to pump blood to the lungs which is a short distance.
23
Q
what are the properties and functions of the heart ventricles?
A
the ventricles have thicker muscular walls than the atria as they have to pump blood out of the heart whereas the atria just pump blood a short distance to the ventricles.
24
Q
where are the atrioventricular valves located and what is their function?
A
atrioventricular (AV) valves link the atria to the ventricles and stop backflow into the atria when the ventricles contract. tendons attach the AV valves to the ventricles to prevent them being forced up into the atria when the ventricles contract.
25
where are the semi-lunar valves located and what is their function?
the semi-lunar (SL) valves link the ventricles to the pulmonary artery and the aorta and stop backflow into the heart after the ventricles contract.
26
how do valves prevent backflow?
the valves only open one way which is dependent on relative pressure of the heart chambers. if there is higher pressure behind a valve, it is forced open but if there is higher pressure in front of the valve it is forced shut. this means blood only flows in one direction through the heart.
27
what is the structure of an artery?
tunica intima- endothelial cells
tunica media- smooth muscle
tunica externa- elastin and collagen (connective tissue)
28
how does the structure of an artery relate to it's function?
arteries mass transport blood AWAY from the heart. smooth endothelial cells minimise friction. thick muscular walls contain the high blood pressure. smooth muscle fibers contract rhythmically on the blood, exerting pressure. elastic fibers absorb the high pressure, expand and 'smooth' large pressure changes and ensure a continuous blood pressure. the elastin allow the vessel to stretch as blood surges through preventing damage. the collagen provides structural support and allows a strong and flexible vessel. as pressure falls the artery recoils releasing energy and pushes the blood on it's way.
29
what is vasoconstriction and vasodilation?
hormones and the sympathetic nerves can stimulate arteriole smooth muscle to contract. vasoconstriction and vasodilation control and direct blood flow in the body as required.
vasodilation= arteriole muscle relaxation
vasoconstriction= arteriole muscle constriction
30
what is the structure of a capillary and how does it relate to it's function?
smaller in diameter than the cells they supply allowing close and intimate contact. the endothelium, supported on the basement membrane, is one cell thick allowing easy exchange across the capillary. fenestrations (gaps) between endothelial cells increases the rate of exchange with tissues. very low blood pressure at the capillary produces a low velocity of blood due to friction with the capillary wall preventing damage to the lung. small lumen, just large enough for a red blood cell to squeeze through. no pulse and no valves.
31
what is the structure of a vein?
tunica intima- endothelial cells
tunica media- less smooth muscle
tunica externa- little elastin and collagen
32
how does the structure of a vein relate to it's function?
veins carry blood at low pressure and velocity. venous walls do not require the thickness and strength of arteries to contain high blood pressure. pressure differences within the venous system are low. valves ensure blood flows only towards the heart after leaving the capillaries. muscles pushing on the veins increase localised pressure and push blood producing flow. relatively large lumen. little elastic tissue in the wall due to low pressure with no surges. no pulse.
33
what is the cardiac cycle?
the cardiac cycle is an ongoing sequence of contraction (systole) and relaxation (diastole) of the atria and ventricles that keeps blood continuously circulating round the body. the volume of the atria and ventricles changes as they contract and relax. pressure changes also occur due to the changes in chamber volume (decreasing volume increases pressure).
34
what happens in phase 1 of the cardiac cycle (Atrial systole)?
blood returns to the heart due to the action of skeletal muscles involved in breathing. blood under low pressure flows into the left and right atria from the pulmonary veins and the vena cava. as the atria fill the increasing pressure of blood forces the AV valves open. the ATRIA WALLS CONTRACT forcing blood into the ventricles.
35
what happens in phase 2 of the cardiac cycle (Ventricular systole)?
the VENTRICLES CONTRACT from the base of the heart upwards, increasing pressure in the ventricles. the pressure forces open the SL valves and pushes blood up and out through the pulmonary arteries and aorta. the pressure of blood against the AV valves close them and prevents backflow into atria.
36
what happens in phase 3 of the cardiac cycle (Cardiac diastole)?
the atria and ventricles then relax. elastic recoil of the relaxing heart walls lowers pressure in the atria and ventricles. blood under high pressure in the pulmonary arteries and aorta is drawn back towards the ventricles closing the SL valves and preventing backflow into the ventricles. the coronary arteries fill during diastole. low pressure in the atria helps draw blood into the heart from the veins.
37
what causes the sounds we recognise as a heartbeat?
the AV and SL valves closing. the first sound 'lub' is caused by the closing of the AV valves and the second 'dub' by the closing of the SL valves.
38
how does the blood move at each stage of the cycle?
from high pressure to low pressure.
39
what is atherosclerosis?
the disease process that leads to coronary heart disease and strokes. in atherosclerosis fatty deposits can either block an artery directly or increase its chance of being blocked by a blood clot (thrombosis).
40
what course of events happen in atherosclerosis? (1)
endothelial dysfunction: the endothelium becomes damaged as a result of high blood pressure (puts extra strain on the layer of cells) or toxins from cigarette smoke in the bloodstream.
41
what course of events happen in atherosclerosis? (2)
inflammatory response: the inner lining of the artery is breached so white blood cells leave the blood vessel and move into the artery wall. these cells accumulate chemicals from the blood, particularly cholesterol. a fatty deposit builds up called an atheroma.
42
what course of events happen in atherosclerosis? (3)
plaque formation: calcium salts and fibrous tissue build up at the site resulting in a hard swelling called a plaque on the inner wall of the artery. the build-up of fibrous tissue means that the artery wall loses some of its elasticity.
43
what course of events happen in atherosclerosis? (4)
raised blood pressure: plaques caused the lumen to become narrower leading to a rise in blood pressure. this causes a positive feedback cycle- plaques lead to raised blood pressure but raised blood pressure increases the chance that further plaques will form as endothelial damage in other areas becomes more likely.
44
why does blood clotting occur inside arteries?
usually blood does not clot inside blood vessels due to the smooth endothelium lining that also has a substance on its surface that repels the platelets. if there is atherosclerosis however and the endothelium is damaged, due to rupture of an atheroma, platelets come into contact with the damaged surface and exposed collagen and the clotting cascade is triggered.
45
what are the stages in the clotting cascade? (1)
platelets stick to the damaged artery wall and to each other, forming a platelet plug. platelets and the damaged tissue release a protein called thromboplastin. thromboplastin release triggers the clotting cascade.
46
what are the stages in the clotting cascade? (2)
thromboplastin activates an enzyme that catalyses the conversion of the protein prothrombin into an enzyme called thrombin. vitamin k and calcium ions need to be present in the blood plasma for this conversion to happen.
47
what are the stages in the clotting cascade? (3)
thrombin then catalyses the conversion of the soluble plasma protein, fibrinogen, into the insoluble protein fibrin.
48
what are the stages in the clotting cascade? (4)
a mesh of fibrin forms that traps more platelets and red blood cells to form a clot.
49
what is a stroke?
a rapid loss of brain function due to a disruption in the blood supply to the brain. this can be caused by a blood clot in the artery leading to the brain which reduces the amount of blood and therefore oxygen that can reach the brain resulting in cell death as respiration cannot be carried out.
50
what is a deep vein thrombosis?
the formation of a blood clot in a vein- usually happens in leg veins. it can be caused by prolonged inactivity e.g. during long haul flights and the risk increases with age
51
what does ischaemic mean?
inadequate flow of blood to part of the body as a result of an artery becoming blocked.
52
how is risk defined?
the probability of occurrence of some unwanted event or outcome usually in the context of anything that could potentially do harm.
53
what is correlation?
how two variables move in relation to each other/ follow the same pattern.
54
what is causation?
one variable directly impacts the other.
55
why would risk be underestimated?
```
the risk is undertaken voluntarily.
the risk is natural .
the risk is familiar.
the risk is not feared.
the risk is fair.
the risk is common.
the consequences are in the future.
```
56
why would risk be overestimated?
```
undertaken involuntarily.
the risk is unnatural.
the risk is unfamiliar.
the risk is feared.
the risk is unfair.
the risk is rare.
the consequences are immediate.
```
57
what lifestyle factors increase the risk of CVD and why? (1)
a diet high in saturated fats- increases blood cholesterol level which increases atheroma formation. atheromas can lead to blood clot formation which can cause a heart attack, stroke or DVT.
a diet high in salt- increases the risk of high blood pressure.
58
what lifestyle factors increase the risk of CVD and why?(2)
high blood pressure- increases endothelial dysfunction which increases the risk of atheroma formation. excessive alcohol consumption, stress and diet can increase blood pressure.
59
what lifestyle factors increase the risk of CVD and why? (3)
smoking- carbon monoxide in cigarette smoke combines with haemoglobin and reduces the amount of oxygen transported in the blood therefore reduces the amount of oxygen available to tissues leading to a heart attack or stroke.
nicotine makes platelets sticky increasing the chance of blood clots forming. smoking also decreases the amount of antioxidants in the blood increasing the risk of cell damage to the artery walls and can lead to atheroma formation.
60
what factors beyond human control increase the risk of CVD and why?
genetics- some people inherit alleles that make them more likely to have high blood pressure or high blood cholesterol.
gender- men are three times more likely to suffer from CVD than pre-menopausal women due to the higher levels of oestrogen in women increases the HDL levels in the blood.
age- risk increases with age partly due to plaque build up overtime.
61
what makes a good study?
sample size- the greater the number of participants the more reliable the results (the sample also needs to be representative).
variables- the more variables that have been controlled the more reliable and valid the results are.
data collection- the less bias involved the more reliable the results.
controls- the presence of controls increases the validity of the results.
repetition- if other scientists produce the same results than the results are more reliable.
62
what is a cohort study?
it follows a large group of participants over time to see who develops the disease and who does not. either a population is followed and then are split into a group who develop the condition and a group who do not or two populations are followed, one exposed to the risk factor and one that is not.
63
what is a case-control study?
a group of people with a disease (case) are compared with a control group of individuals who do not have the disease. information is collected about the risk factors that the participants have been exposed to in the past. these studies are retrospective.
64
what is oedema?
a symptom of high blood pressure where fluid enters the tissues causing swelling.
65
what is tissue fluid?
bathes every cell in the body supplying them with glucose, amino acids, fatty acids, salts and oxygen. is very similar to plasma but does not have large plasma protein molecules.
66
how is tissue fluid formed?
blood under high pressure forces fluid and small molecules from blood plasma out of the capillary walls into intercellular spaces.
67
what are the three types of carbohydrate?
monosaccharides
disaccharides
polysaccharides
68
why are carbohydrates important?
cells use carbohydrates as a source of energy and a way of storing energy. plants store sugar in the form of starch. animals form sugar as glycogen.
69
what three molecules are carbohydrates made of ?
carbon, hydrogen and oxygen.
70
what are isomers?
have the same formula but a slightly different structure.
71
what are monosaccharides?
| Give three examples.
single sugars that provide a rapid source of energy and have the same number of carbon and oxygen atoms.
e. g. glucose: used in all cells for respiration, is made during photosynthesis, has two structural isomers (alpha and beta). main energy source in animals and plants and is soluble so is easily transported. contains 6 carbon atoms.
e. g. galactose (part of lactose): found as part of a lactose sugar in our diet, both OH groups on C1 and C4 above.
e. g. fructose: found in honey, fruit and veg, very sweet.
72
what is the difference structurally between alpha and beta glucose?
in alpha glucose, the hydroxyl group is attached facing down and away from the main structure, while in the beta glucose, the hydroxyl group is attached above the ring and on the first carbon.
73
what are disaccharides?
| Give three examples.
made of two monosaccharides joined together by a condensation reaction which removes water and forms a glycosidic bond.
e. g. maltose: made of alpha glucose+ alpha glucose, found in germinating seed, 1-4 glycosidic bond.
e. g. sucrose: made of alpha glucose + fructose, stored in plants such as sugar cane, 1-2 glycosidic bond.
e. g. lactose: made of galactose + beta glucose, found in milk, 1-4 glycosidic bond.
74
what is the opposite of a condensation reaction?
hydrolysis reaction. water is put back in breaking the glycosidic bonds in the case of disaccharides and polysaccharides.
75
what are polysaccharides?
formed when two or more monosaccharides join together through multiple condensation reactions. perfect for storing sugar in a cell as insoluble so don't affect water potential and are compact therefore take up little space.
76
what is the structure of starch (a polysaccharide)?
made up of two polysaccharide compounds: AMYLOSE (200 to 5000 alpha glucose molecules all joined by C1,C4 glycosidic bonds) and forms a coil.
AMYLOPECTINE (branched polymer of alpha glucose molecules made up from a combination of C1,C4 and C1,C6 glycosidic bonds which forms branches which are easily broken of to give a quick release of energy).
77
what is the structure of glycogen (a polysaccharide)?
made up of many alpha glucose molecules and a combination of C1,C4 and C1,C6 glycosidic bonds forming branches which break of easily to release energy. has more branching than amylopectin.
78
what is the structure of cellulose (a polysaccharide)?
made of beta glucose molecules joined by C1,C4 glycosidic bonds. every other molecule is inverted to allow the bond to be regular resulting in a straight molecule. strands of straight molecules can be joined using HYDROGEN BONDS between them and that will form FIBRILS which can be bonded together to make FIBRES, strong material.
79
what are the functions of polysaccharides?
- starch in plants allow a mixture of quick and slow release energy due to the mixture of amylose and amylopectin.
- amylopectin in plants and glycogen in animals is a source of fast release energy due to the side chains of glucose are easily broken down so glucose is released quickly.
- cellulose is very hard to digest as we don't have the enzymes required to break down the glycosidic bonds between the beta glucose molecules.
- starch is the main energy storage material material in plants and glycogen is the main energy storage material in animals.
80
what is a lipid and what are the two main types?
an organic molecule composed of carbon, hydrogen and oxygen with two main types: triglycerides and phospholipids. lipids are large molecules (macromolecules) but are not polymers as each of the units are not monomers. are non-polar molecules ( do not dissolve in water) due to the fatty acid hydrocarbon tail which is hydrophobic.
triglycerides are a good source of energy (oil and butter) and phospholipids have a structural role in cell membranes.
81
what is the structure of triglycerides?
made up of one molecule of glycerol and three fatty acids.
GLYCEROL is an organic alcohol (a carbon chain with (-OH) groups attached) which contains three hydroxyl (-OH) groups.
FATTY ACIDS are organic acids (can lower the pH of things) that have a carboxyl (-COOH) group joined to a hydrocarbon tail, are a type of carboxylic acid.
82
how are triglycerides formed?
formed by condensation reactions and broken up by hydrolysis reactions.
three fatty acids and a single glycerol molecule are joined together by ESTER BONDS.
a hydrogen atom on one glycerol molecule bonds to a hydroxyl (OH) group on the fatty acid, releasing a molecule of water.
each of the fatty acids in the triglyceride is attached to the glycerol molecule by an ester bond.
83
what is the structure of saturated lipids?
- contains the maximum number of hydrogen atoms.
- the hydrocarbon chain is long and straight.
- no carbon double bonds.
- solid at room temperature (due to strong intermolecular bonds between triglycerides).
84
what is the structure of unsaturated lipids?
- have carbon double bonds causing the unsaturated hydrocarbon chain to kink.
- one carbon double bond (monounsaturated)
- multiple carbon double bonds (polyunsaturated)
- oils at room temperature (distance between molecules due to the kink weakens intermolecular forces)
85
where are saturated lipids found?
animal fats from meat and dairy products.
86
what are good sources of unsaturated fats?
vegetable oils, nuts, fish
87
what are trans fats?
unsaturated fats can be made more solid at room temperature by adding hydrogen to the double bonds making them saturated.
these trans fats are produced by the food industry and used in processed foods.
trans fats do occur naturally at very low levels in meat and diary products.
88
how does a diet high in saturated fat increase the risk of developing CVD?
by increasing blood cholesterol (high LDL level)
89
what are lipoproteins?
cholesterol is a type of lipid which needs to be attached to protein to be transported- so the body forms lipoproteins.
90
what are HDLs?
| high density lipoproteins
- mainly protein.
- transport cholesterol from body tissues to the liver where it is recycled or excreted.
- their function is to REDUCE TOTAL BLOOD CHOLESTEROL when the level is too high.
91
what are LDLs?
| low density lipoproteins
- mainly lipid.
- transport cholesterol from the liver to the blood, where it circulates until needed by cells.
- their function is to INCREASE BLOOD CHOLESTEROL when the level is too low.
92
what is meant by total blood cholesterol?
the level of HDL, LDL and other cholesterol.
93
give two examples of obesity indicators and how are they useful.
waist to hip ratio
BMI (body mass index)
-can be used to monitor the effects any changes in lifestyle have on the person's weight.
94
how has scientific research reduced people's risk of coronary heart disease?
```
scientific studies have been carried out to identify risk factors and these results are published in scientific journals.
government organisations (e.g NHS) and the media report the findings to the general public.
people can use this information to make choices about their lifestyle, so they can reduce their chance of developing CVD.
```
95
what is energy balance?
a term used to describe the amount of energy taken in by an organism (in food) and the amount of energy used up by an organism (e.g by moving).
if there is an imbalance in energy budget, it will affect a persons weight.
96
how is weight gained?
if energy intake is higher than energy output, the excess energy will be turned into fat reserves by the body.
97
how is weight lost?
if energy intake is lower than energy output, the body will have to get more energy from somewhere, it will turn some of its fat reserves into energy so the person will lose weight.
98
how does obesity develop?
if the energy difference is a lot and is sustained over a long period of time, the person could become obese.
99
what are the ethical issues regarding the use of invertebrates in research?
- cannot give consent and they may be subjected to painful procedures.
- more acceptable to perform experiments on invertebrates than on vertebrates as they have a less sophisticated nervous system.
- unethical to cause distress or suffering to any living organism.
100
what are antihypertensives?
drugs that reduce blood pressure so there is less chance of damage occurring to the walls of the arteries. this reduces the risk of atheromas forming and blood clots developing.
101
what are examples of antihypertensives?
beta blockers (reduce the strength of the heartbeat).
vasodilators (which widen the blood vessels).
diuretics (reducing the amount of sodium that is reabsorbed by the blood in the kidneys, resulting in less water being reabsorbed due to osmosis, which reduces blood volume).
102
what are the benefits of antihypertensives?
different hypertensives work differently so they can be given in combination to reduce blood pressure.
blood pressure can be measured at home so the patient can see if the drugs are working.
103
what are the risks of antihypertensives?
palpitations, abnormal heart rhythms, fainting, headaches, drowsiness, allergic reactions and depression.
104
what are statins?
drugs that reduce blood cholesterol by reducing the amount of LDLs produced inside the liver.
a lower blood cholesterol level reduces atheroma formation which reduces the risk of CVD.
105
what are the benefits of statins?
reduce the risk of developing CVD
106
what are the risks of statins?
muscle and joint pain, digestive system problems, increased risk of diabetes, nosebleeds, headaches and nausea.
107
what are anticoagulants?
drugs that reduce blood clotting.
blood clots are less likely to form at sites of damage in artery walls so there is less chance of a blood vessel becoming blocked by a blood clot, reducing the risk of CVD.
108
what are examples of anticoagulants?
warfarin
| heparin
109
what are the benefits of anticoagulants?
can be used to treat people who already have blood clots or CVD, they prevent any existing blood clots from growing any larger and prevent any new blood clots from forming.
however, anticoagulants can't get rid of existing blood clots.
110
what are the risks of anticoagulants?
if a person taking these drugs is injured, the reduction in blood clotting can cause excessive bleeding which can lead to fainting and death.
other side effects include allergic reactions, osteoporosis and swelling of the tissues.
can damage the fetus if taken during pregnancy.
111
what are platelet inhibitory drugs?
a type of anticoagulant which work by preventing platelets clumping together to form a blood clot so they reduce the formation of blood clots.
112
what is an example of platelet inhibitory drugs?
asprin
113
what are the benefits of platelet inhibitory drugs?
can be used to treat people who already have blood clots or CVD
114
what are the risks of platelet inhibitory drugs?
rashes, diarrhoea, nausea, liver function problems and excessive bleeding (especially after serious injury)
