Topic 1: Lifestyle, Health and Risk part 1 Flashcards
open circulatory system
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
closed circulatory system
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
single circulatory system (fish)
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
double circulatory systems
Has two different circuits of blood
systemic circuit: lungs -> heart -> body
pulmonary circuit: body -> heart -> lungs
what is mass flow
the bulk movement of substances due to pressure differences, occurs over large distances in organisms
it allows faster movement than diffusion
characteristics of arteries
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
characteristics of veins
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
capillary characteristics
endothelium - one cell THICK to speed up diffusion
capillaries form a capillary bed that surrounds the target location
name the three phases of mass transport (in order)
Atrial systole
ventricular systole
cardiac diastole
atrial systole
ventricular systole
what do systole and diastole mean
systole - contract
diastole - relax
describe cardiac diastole
- 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
describe atrial systole
- 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)
describe ventricular systole
- 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
what is happening at point A
• 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
what is happening at point B
• 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
what is happening at point D
• the atrioventricular valve opens so the blood can flow, aorta –> ventricle
why does the atrium always have a lower pressure
the muscle layer is thinner than around the ventricle
why do the aorta and ventricles have very similar pressures in the middle
because they are very close to each other
why is there a high proportion of elastic fibres in arteries near the heart
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
what type of molecule is water
a polar molecule - it is partially negative on one side and partially positive on the other
properties of water due to its type of molecule
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
define atherosclerosis
the hardening of an artery caused by an atheroma, a type of atherosclerosis
what is an atheroma
a build of fatty tissue, particularly LDL cholesterol
why do only arteries get atherosclerosis
arteries have fast-flowing blood under high pressure, so there’s a significant chance of damage to walls
describe the process of atherosclerosis
- endothelial dysfunction (damage to the artery lining)
- inflammatory response, causes white blood cells to move to the wall of the artery
- atheroma (initially soft) forms due to the fatty deposit, primarily cholesterol
- (hard) plaque builds up due to calcium salts and fibrous tissue
- artery lumen narrows leading to an increase in blood pressure
- this leads to a positive feedback loop which can become very dangerous with regards to blood pressure (keeps narrowing, pressure keeps increasing)
describe thrombosis (blood clotting)
- platelets stick to the damaged wall (collagen) of the blood vessel
- this releases the thromboplastin enzyme from platelets and damaged tissue leading to the cascade of reactions
- thromboplastin catalyses the conversion of the soluble plasma protein prothrombin into the enzyme thrombin
- thrombin catalyses the conversion of another soluble plasma protein, fibrinogen into fibrin
- fibrin is a long, insoluble protein strand; these strands form a tangled mesh and trap blood to form a clot
when might someone overestimate risk
if the risk is:
not under their control, involuntary
not natural
sudden consequence
constant media exposure
personal surroundings
very small
when might someone underestimate risk
if they don’t have the full information/unaware of the dangers
personal surroundings
the consequences are long term
why are ciliated columnar epithelia known as pseudostratified
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
what are glycoproteins
proteins with carbohydrates bound to them (integral and peripheral proteins)
fully label a heart
why is thrombosis important
it prevents blood loss
prevents entry of disease causing micro-organisms
it provides a framework for repair
how does smoking increase CVD risk
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
how does hypertension increase CVD risk
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)
how does age increase CVD risk
plaque built up over time
how does a high PAL decrease CVD risk
activity can raise HDL levels without affecting LDL levels, lack of activity increases bp
how does gender affect CVD risk
men are more likely to get CVD bc oestrogen in women increases HDL, which can decrease overall cholesterol
devise an experiment to look at the effect of caffeine on heart rate
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
compare the aorta and pulmonary artery
aorta has more collagen+elastictissue+muscular tissue
collagen - withstands hbp
elastic and muscular tissue - maintains hbp
side effects of drugs
nausea
fainting
what treatment options are there for CVD
- antihypertensives
- statins
- anticoagulants
- platelet inhibitory drugs
outline and evaluate antihypertensives as a CVD treatment
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
outline and evaluate statins as a CVD treatment
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
outline and evaluate anticoagulants as a CVD treatment
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
outline and evaluate platelet inhibitory drugs as a CVD treatment
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
what is a mass transport system
The bulk movement of gases or liquids in one direction, usually via a system of vessels and tubes
compare an artery with a vein
add pic
how do you use a light microscope
- clip the slide with the specimen onto the stage
- select the lowest-powered objective lens
- bring the stage up, to just below the objective lens using the coarse adjustment knob
- look down the eyepiece and use the coarse adjustment knob to move the stage down until the image is roughly in focus
- use the fine adjustment knob to adjust the focus, until the slide image is clear
- for greater magnification, switch to a higher powered objective lens and refocus
how is an eyepiece graticule used
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
why do diuretics work
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
how do red blood cells carry oxygen
their biconcave disc shape increases the SA:V and allows oxygen to easily diffuse into the cells
6 mark q
repeats so that you can find the mean and use the student’s t-test
what does it mean if two things have more similarities
that they have more recently evolved from a common ancestor
why is it good to use just one test subject
higher levels of control which increases validity
why would you use a control group
to see the effect that the independent variable has on
how do artery walls differ from veins
more elastic tissue for recoil
more collagen to withstand pressure
more muscle tissue to maintain pressure
why can things like aging/smoking/radiation cause cancer
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
