Topic 1: Lifestyle, Health and Risk part 1

Question 1

open circulatory system

Answer 1

found in insects
blood circulates in large open spaces
low rate of diffusion, only works with a low SA/ ratio
a simple heart pumps blood into the cavities surrounding the animals organs
substances diffuse between the blood and cells
blood is drawn back when the heart muscle relaxes

Question 2

closed circulatory system

Answer 2

found in all vertebrates and larger animals
the blood is enclosed in tubes, generating a higher bp as the blood is forced along fairly narrow channels
blood travels faster so this system is quite efficient at delivering substances

Question 3

single circulatory system (fish)

Answer 3

blood only flows around once
eg, a fish
heart pumps deoxygenated blood to gills where CO2 goes from blood to water surrounding the gills and O2 goes from that water to the blood
the blood then circulates the body before returning to the heart

Question 4

double circulatory systems

Answer 4

Has two different circuits of blood
systemic circuit: lungs -> heart -> body
pulmonary circuit: body -> heart -> lungs

Question 5

what is mass flow

Answer 5

the bulk movement of substances due to pressure differences, occurs over large distances in organisms

it allows faster movement than diffusion

Question 6

characteristics of arteries

Answer 6

large lumen, but smaller than a vein - accommodates large volumes of blood

thicker walls - withstands the high pressure blood

folded endothelium - increases friction which slows the blood (that’s okay bc it’s already high speed+pressure)

folded so it can expand with vasodilation, but it’s smooth

thick muscle handles the high blood pressure

middle layer - arteries near to the heart have more elastic fibres and those further have more muscle tissue

no valves

outer coat - collagen fibres and connective tissue for strength and support

Question 7

characteristics of veins

Answer 7

outer coat - collagen fibres with connective tissue
wide lumen - keeps a low pressure but a higher volume
thinner walls - only low pressure, doesn’t need to be as strong
endothelium - smooth, prevents friction which would slow it down
valves - prevent back flow of blood
less collagen because of lower pressure

Question 8

capillary characteristics

Answer 8

endothelium - one cell THICK to speed up diffusion
capillaries form a capillary bed that surrounds the target location

Question 9

name the three phases of mass transport (in order)

Answer 9

Atrial systole
ventricular systole
cardiac diastole
atrial systole
ventricular systole

Question 10

what do systole and diastole mean

Answer 10

systole - contract
diastole - relax

Question 11

describe cardiac diastole

Answer 11

• the atria and ventricles relax
• ventricle pressure drops below that of the arteries, forcing SL valves to close
• atria continue filling with blood
• atrial pressure increases above ventricular pressure, forcing open AV valves
• blood passively flows into ventricles

Question 12

describe atrial systole

Answer 12

• atrial walls contract, decreasing volume and increasing pressure
• atrial pressure > ventricular pressure, forcing AV valves open
• blood forced into ventricles, slightly increasing their pressure
  (ventricular diastole is occurring simultaneously)

Question 13

describe ventricular systole

Answer 13

• ventricle walls contract, decreasing volume and increasing pressure
• ventricle pressure>atrial pressure forces AV valves closed
• ventricle pressure>artery pressure, forcing SL valves open and forcing blood out of the heart
  (atrial diastole is occurring simultaneously) so atria begin filling with blood

Question 14

what is happening at point A

Answer 14

• from the beginning to point A, atrial systole is occurring
• at A the AV valves close (blood is in the ventricles already), so atrium pressure dips slightly

Question 15

what is happening at point B

Answer 15

• between points A and D is ventricular systole
• at B the semilunar valve opens, so aortic pressure increases because the blood can go in
• the pressure in the ventricle rises due to contractions
• pressure continues to increase in both the ventricle and aorta as the blood goes to the aorta from the ventricle

Question 16

what is happening at point D

Answer 16

• the atrioventricular valve opens so the blood can flow, aorta –> ventricle

Question 17

why does the atrium always have a lower pressure

Answer 17

the muscle layer is thinner than around the ventricle

Question 18

why do the aorta and ventricles have very similar pressures in the middle

Answer 18

because they are very close to each other

Question 19

why is there a high proportion of elastic fibres in arteries near the heart

Answer 19

they have to be able to withstand the pressure of the sprouts of blood and stretch to accommodate the increased volume
it also helps them to even out the blood pumped to give a continuous flow

Question 20

what type of molecule is water

Answer 20

a polar molecule - it is partially negative on one side and partially positive on the other

Question 21

properties of water due to its type of molecule

Answer 21

cohesive and adhesive properties - it’s dipolar nature allows the formation of hydrogen bonds between hydrogen and oxygen
cohesion is between water molecules
adhesion is between water and other molecules
- makes it ideal for substance transportation

good solvent - it is a dipolar substance, so ionic compounds (electrolytes) can dissolve in it - dissolved substances can be transported over large distances

high specific heat capacity - remains liquid over a wide temp range; high SCH also allows water to maintain a fairly constant temp which is ideal for mammals and marine animals

Question 22

define atherosclerosis

Answer 22

the hardening of an artery caused by an atheroma, a type of atherosclerosis

Question 23

what is an atheroma

Answer 23

a build of fatty tissue, particularly LDL cholesterol

Question 24

why do only arteries get atherosclerosis

Answer 24

arteries have fast-flowing blood under high pressure, so there’s a significant chance of damage to walls

Question 25

describe the process of atherosclerosis

Answer 25

1. endothelial dysfunction (damage to the artery lining) 2. inflammatory response, causes white blood cells to move to the wall of the artery 3. atheroma (initially soft) forms due to the fatty deposit, primarily cholesterol 4. (hard) plaque builds up due to calcium salts and fibrous tissue 5. artery lumen narrows leading to an increase in blood pressure 6. this leads to a positive feedback loop which can become very dangerous with regards to blood pressure (keeps narrowing, pressure keeps increasing)

Question 26

describe thrombosis (blood clotting)

Answer 26

1. platelets stick to the damaged wall (collagen) of the blood vessel 2. this releases the thromboplastin enzyme from platelets and damaged tissue leading to the cascade of reactions 3. thromboplastin catalyses the conversion of the soluble plasma protein prothrombin into the enzyme thrombin 4. thrombin catalyses the conversion of another soluble plasma protein, fibrinogen into fibrin 5. fibrin is a long, insoluble protein strand; these strands form a tangled mesh and trap blood to form a clot

Question 27

when might someone overestimate risk

Answer 27

if the risk is: not under their control, involuntary not natural sudden consequence constant media exposure personal surroundings very small

Question 28

when might someone underestimate risk

Answer 28

if they don't have the full information/unaware of the dangers personal surroundings the consequences are long term

Question 29

why are ciliated columnar epithelia known as pseudostratified

Answer 29

ciliated columnar epithelia appear stratified (made of layers) - but each cell is in contact with the basement membrane they appear that way as some cells have their nucleus in the centre vs the bottom of the cell the epithelium is therefore know as pseudostratified

Question 30

what are glycoproteins

Answer 30

proteins with carbohydrates bound to them (integral and peripheral proteins)

Question 31

fully label a heart

Answer 31

Question 32

why is thrombosis important

Answer 32

it prevents blood loss prevents entry of disease causing micro-organisms it provides a framework for repair

Question 33

how does smoking increase CVD risk

Answer 33

haemoglobin in blood cells will carry CO from the smoke instead of O, this causes increased bp bc the body still has to provide enough oxygen the chemicals can cause endothelial dysfunction tar can reduce lung SA, reducing gaseous exchange efficiency

Question 34

how does hypertension increase CVD risk

Answer 34

it increases the amount of wear and tear in your arteries as they have to work harder increases the likelihood of endothelial dysfunction (positive feedback loop)

Question 35

how does age increase CVD risk

Answer 35

plaque built up over time

Question 36

how does a high PAL decrease CVD risk

Answer 36

activity can raise HDL levels without affecting LDL levels, lack of activity increases bp

Question 37

how does gender affect CVD risk

Answer 37

men are more likely to get CVD bc oestrogen in women increases HDL, which can decrease overall cholesterol

Question 38

devise an experiment to look at the effect of caffeine on heart rate

Answer 38

get enough daphnia that you have 30 to work with - similar ages 1. make up caffeine solutions - 0% (control), 20%, 40%, 60%, 80% and 100% 2. transfer one daphnia onto the dimple in a cavity slide 3. place 3 drops of caffeine solution onto the daphnia 4. wait 5 minutes for the caffeine to be absorbed 5. place the light on the light microscope stage and adjust the focus to see the daphnia's beating heart, Sts the backside of the gut 6. count the number of heartbeats in 20 seconds using a clicker and timing with a stopwatch. multiple by 3 to get heart rate in bpm 7. repeat 3 times for each setting and calculate means 8. do a statistical test to see if results are statistically significant

Question 39

compare the aorta and pulmonary artery

Answer 39

aorta has more collagen+elastictissue+muscular tissue collagen - withstands hbp elastic and muscular tissue - maintains hbp

Question 40

side effects of drugs

Answer 40

nausea fainting

Question 41

what treatment options are there for CVD

Answer 41

1. antihypertensives 2. statins 3. anticoagulants 4. platelet inhibitory drugs

Question 42

outline and evaluate antihypertensives as a CVD treatment

Answer 42

beta blockers - reduce strength of heart beat vasodilators - widen blood vessels diuretics - reduce blood volume by reducing sodium reabsorbed by blood in kidneys and so less water reabsorption + diff. antihypertensive types work differently, so can be combined to reduce bp + bp can be monitored at home so pt can se if drugs are working -- side effects: palpitations, abnormal heart rhythms, fainting, headaches, depression, allergic

Question 43

outline and evaluate statins as a CVD treatment

Answer 43

they reduce LDL cholesterol produced in liver, reducing blood cholesterol. this reduces atheroma formation and so CVD risk + reduced CVD development risk -- increased diabetes risk, nosebleeds, muscle and joint pain, nausea and digestive system issues

Question 44

outline and evaluate anticoagulants as a CVD treatment

Answer 44

eg. warfarin and heparin reduce blood clotting so blood clots are less likely to form if artery walls are damaged so less chance of blood vessel blockage by one + can treat ppl with existing clots/CVD to prevent existing ones form growing and new from developing -- if badly injured, bleeding can be excessive --> fainting or even death -- can't get rid of exiting blood clots

Question 45

outline and evaluate platelet inhibitory drugs as a CVD treatment

Answer 45

eg. aspirin a type of anticoagulant that prevents platelets clumping to form a blood clot, this reduced blood clot formation and the chance of them causing a blood vessel blockage + can treat ppl with existing clots/CVD to prevent existing ones form growing and new from developing -- side effects; rashes, diarrhoea, excessive bleeding, liver function issues

Question 46

what is a mass transport system

Answer 46

The bulk movement of gases or liquids in one direction, usually via a system of vessels and tubes

Question 47

compare an artery with a vein

Answer 47

add pic

Question 48

how do you use a light microscope

Answer 48

1. clip the slide with the specimen onto the stage 2. select the lowest-powered objective lens 3. bring the stage up, to just below the objective lens using the coarse adjustment knob 4. look down the eyepiece and use the coarse adjustment knob to move the stage down until the image is roughly in focus 5. use the fine adjustment knob to adjust the focus, until the slide image is clear 6. for greater magnification, switch to a higher powered objective lens and refocus

Question 49

how is an eyepiece graticule used

Answer 49

the graticule is added on to the eyepiece lens and has no set measurements, varying with magnification a stage micrometer (microscope slide ruler) is used to calibrate the graticule

Question 50

why do diuretics work

Answer 50

they remove more water and salt less water lowers blood volume and so pressure less salt lowers uptake of water into blood via osmosis from tissue fluid and so, blood pressure

Question 51

how do red blood cells carry oxygen

Answer 51

their biconcave disc shape increases the SA:V and allows oxygen to easily diffuse into the cells

Question 52

6 mark q

Answer 52

repeats so that you can find the mean and use the student’s t-test

Question 53

what does it mean if two things have more similarities

Answer 53

that they have more recently evolved from a common ancestor

Question 54

why is it good to use just one test subject

Answer 54

higher levels of control which increases validity

Question 55

why would you use a control group

Answer 55

to see the effect that the independent variable has on

Question 56

how do artery walls differ from veins

Answer 56

more elastic tissue for recoil more collagen to withstand pressure more muscle tissue to maintain pressure

Question 57

why can things like aging/smoking/radiation cause cancer

Answer 57

the chemicals can damage DNA by changing the base sequence and with age there is more cell division, so a greater change of an error in the base sequence during replication