1 Heart, CVD, Carbs and Lipids Flashcards
explain how dipolar nature of water is essential for living organisms
- water can form H-bonds
- this holds water together as liquid so can MOVE IN MASS FLOW SYSTEMS
- has LARGE SPECIFIC HEAT CAPACITY = lots of energy needed to change temp
- so good as EXTERNAL BUFFER
sucrose
ɑ glucose + fructose
condensation reaction forming glycosidic bonds
lactose
ɑ glucose + galactose
condensation reaction forming glycosidic bonds
maltose
ɑ glucose + ɑ glucose
condensation reaction forming glycosidic bonds
(cellulose)
MORE IN TOPIC 4
- only in plants
- polymer of long chains of β-glucose joined together by 1,4 glycosidic bonds
systole
S uck
C ock
contraction
diastole
relaxation
explain how structure of artery wall is adapted both to withstand and to maintain high b.p
- endothelium is ONE CELL THICK and lines lumen of all blood vessels -> v smooth and reduces FRICTION
- endothelium is HIGHLY FOLDED -> lets it expand under high b.p
- SMOOTH MUSCLE and ELASTIC TISSUE STRENGTHEN arteries so can withstand high b.p
what is cardiac muscle made up of?
cells connected by cytoplasmic bridges
-> enables electrical impulses to pass through tissue
what is the role of valves in the heart?
- prevent back flow of blood
- maintaining correct pressure in chambers
how are left and right side of heart different and why?
LHS is thicker as has to pump blood further and so at HIGHER PRESSURE
RHS is thinner as not at high pressure as might DAMAGE DELICATE LUNG TISSUE
how is cardiac muscle different to skeletal muscle?
MYOGENIC -> originating in muscle tissue
describe two blood vessels that bring blood INTO heart
VENA CAVA -> brings blood from body (deoxygenated)
PULMONARY VEIN -> brooms blood from lungs (oxygenated)
describe two blood vessels that bring blood AWAY FROM heart
PULMONARY ARTERY -> takes blood to lungs (deoxygenated)
AORTA ->takes blood to body (oxygenated)
artery
- narrow lumen -> maintains high b.p
- elastic fibres -> allow stretch and recoil
- thicker muscular wall -> contracts and relaxes to CONSTRICT and DILATE BLOOD VESSELS
- collagen in walls -> provides strength to withstand high b.p
- folded endothelium -> allows EXPANSION -> cope with high b.p
myogenic
ability of muscles to make its own electrical impulses at rest (without CNS)
explain how veins are adapted to their function
- large lumen -> low b.p and minimises resistance
- thin layer of elastic tissue -> maintains b.p
- valves -> prevent back flow
- smooth endothelium -> minimise resistance
capillaries
where metabolic exchange occurs
-> subs exchanged between cells and capillaries
- network of capillaries -> increase s.a for metabolic exchange
- one cell thick walls -> speeds up diffusion of substances (eg. glucose, O₂) in and out of cells
what drugs can be taken to treat CVD?
-
antihypertensives
-> reduces high b.p -
statins
-> reduce cholesterol -
anticoagulants
-> reduce formation of blood clot -
platelet inhibitory drugs
-> reduce formation of blood clot
compare the benefits and risks of STATINS
adv.?
- reduce risk of developing CVD
disadv.? -
- muscle/joint pain
- dig system problems
- increases risk diabetes
- nosebleeds, headaches, nausea
compare the benefits and risks of ANTIHYPERTENSIVES
adv.?
- diff. types of hypertensives work in diff. ways so can be given COMBO.
disadv.?
- palpitations
- abnormal heart rhythms
- fainting
- headaches
- drowsiness
all side effects caused by LOW B.P
compare the benefits and risks of ANTICOAGULANTS
adv.?
- treat ppl who ALREADY have blood clots / CVD
-> prevent clots growing larger and prevents new clots
disadv.?
- can’t get rid of EXISTING clots
- if patient badly injured -> excessive bleeding
= fainting and death
- osteoporosis
- swelling of tissues
- CAN DAMAGE FEOTUS
why are daphnia selected to investigate effect of caffeine on heart rate?
- transluscent bodies so heart rate is more easily observed
- less developed CNS to humans so reduced awareness of pain
- very common so no threat to extinction or dependent species (via food chain)
how does caffeine work in humans?
stimulant that increases heart rate by increasing release of excitatory neurotransmitters
(for daphnia practical)
how is control set up?
replace caffeine sol with distilled water to measure daphnia heart rate without effect of caffeine
what steps should students take to ensure daphnia are ethically treated?
- return to natural habitat after use
- minimise amount of time exposed to stressful conditions
why should cover slip not be used when observing organism?
(daphnia practical)
to allow O₂ to reach organism
-> preventing conditions from becoming ANOXIC
what is the purpose of placing cotton wool on the slide?
(daphnia practical)
to restrict movement of organism so easier to count heart rate
outline procedure for investigating the effect of caffeine on heart rate in daphnia
- dilute caffeine sol to 5 diff conc
- place cotton wool on cavity slide and add 1 daphnia -> use filter paper to absorb excess water
- use dropping pipette to add few drops DISTILLED WATER to slide
- use stopwatch to time a min and record no. of heartbeats (bpm)
- repeat experiment -> replacing distilled water with diff caffeine sol
- repeats then carried out with 2 OTHER DAPHNIA
what reagent is used to test for vitamin C and what is observed?
DCPIP
colour change from
blue -> colourless
outline procedure to use DCPIP to find vitamin C content of diff samples
- pipette 1cm³ 1% blue DCPIP sol into conical flask
- fill burette with 1% vitamin C sol and note start value
- using burette, slowly add vitamin C to DCPIP DROPWISE -> swirl flask
- close tap as soon as DCPIP decolourises and note end value
- record vol of vitamin C required to change colour of DCPIP
- repeat experiment and replace vitamin C sol with fruit juices
state a hazard and safety precaution for vitamin C practical
DCPIP -> irritant
-> wear goggles and avoid skin contact
compare the benefits and risks of PLATELET INHIBITORS
adv.?
- used to treat ppl who ALREADY have blood clots
disadv.?
- rashes
- diarrhoea
- nausea
- liver function problems
- excessive bleeding -> especially after serious injury
discuss the potential ethical issues of using invertebrates in scientific research
AGAINST
- can’t give consent
-
unethical to cause distress / suffering to ANY organism
-> eg. subjecting them to extreme temp / depriving them of food
FOR
- invertebrates have less developed CNS -> feel less/no pain
- more distantly related to humans that other
vertebrates - daphnia are v common -> no chance of extinction
glycogen
main energy storage in animals -> animals store excess glucose as glycogen
- 1,4 and 1,6 glycosidic bonds with LOADS of branches …
- so stored glucose can be released quickly (important for energy release in animals)
- also v compact -> so good for storage
- insol in H₂O so doesn’t cause cells to swell via osmosis
- large -> so can store LOTS of energy
starch
main energy store in plants -> plants store excess glucose as starch
(when it needs more energy = breaks down starch to release glucose)
- insol in H₂O -> doesn’t cause cells to swell via osmosis so good for storage
- made of 2 polysaccharides of ɑ-glucose…
-> amylose and amylopectin
AMYLOSE
- long unbranched chain of ɑ-glucose joined by 1,4 glycosidic bonds
- coiled = compact -> so good for storage and can fit more into small space
AMYLOPECTIN
- long branched chain of ɑ-glucose joined by 1,4 and 1,6 glycosidic bonds
- side branches allow enzymes that break down molecule to get at glycosidic bonds easily
-> so glucose can be released quickly
how do monosaccharides’ and disaccharides’ structure relate to their roles in storing energy?
structure makes them sol so can be easily transported and chemical bonds contain lots of energy
- disaccharide not as sol as mono.
- disaccharide chemical bonds store more energy
how is triglyceride synthesised?
- via condensation reaction (releases H₂O) …
- between glycerol and 3 fatty acids
- joined by ester bonds
explain why lipids are insol in H₂O
triglyceride (kind of lipid) made of glycerol and 3 fatty acid tails
- fatty acid molecules have long tails of hydrocarbons
- tails are hydrophobic …
- so insol in H₂O
what is the difference between sat. and unsat. lipids?
- sat. lipids don’t have double C bonds (C=C) in hydrocarbon tails -> each C attached to at least 2 H
- unsat. lipids have double C=C bonds in hydrocarbon tails
-> causes kink in tail
- if lipids has 2+ double C bonds -> called polyunsat.
body mass index (BMI)
body mass (kg)
÷
height ² (m²)
units should be kg m⁻²
waist-to-hip ratio
waist (cm)
÷
hip (cm)
suggest how obesity indicators are used to assess if ppl are obese / overweight and how this relates to CVD
- obesity indicators (waist-to-hip ratio, BMI) used to assess obesity
- results of these compared to ‘normal’ values in published data table
- obese ppl more likely to develop CVD
- these obesity indicators can be used to monitor effects any changes in lifestyle have on person’s weight
suggest why people’s perceptions of risks are often diff from actual risks of eg. CVD
under/overestimating risks
overestimating risk because …
- constant media exposure of articles to do with risk makes ppl constantly worry they’ll get eg. CVD
- personal experience -> eg. known someone who smoked and died of CVD so think if you smoke you must get CVD
underestimating risk because …
- lack of info making them unaware of factors that contribute to diseases like CVD
describe the blood clotting process
(3 marks)
- thromboplastin (protein) released from damaged blood vessel
- thromboplastin + Ca²⁺ (from plasma) trigger conversion of …
prothrombin (sol protein)->thrombin (enzyme) - thrombin catalyses conversion of …
fibrinogen (sol protein)->fibrin (solid insol fibres) - fibrin fibres tangle together to form mesh where platelets and RBCs get trapped -> forms blood clot!
CVD can result from blood clots!!!!!!
describe the course of events that lead to atherosclerosis
- damage to endothelium in artery (by eg. high b.p) -> causes inflammatory response -> WBCs move into area
- WBCs and lipids from blood clump together under endothelium to form fatty streaks
- over time, more WBCs, lipids and connective tissue build up -> form fibrous plaque = atheroma
- plaque partially blocks lumen of artery and restricts blood flow -> causes b.p to increase
- hardening of arteries caused by atheromas = atherosclerosis
explain how the relationship between heart structure and function can be investigated practically
(5 marks)
heart dissection
external examination:
- see 4 main vessels attached to heart
- feel of vessels used to identify each one -> arteries are thick and rubbery, veins are thinner
- see RA, LA, RV, LV and coronary arteries
internal examination:
- LV wall is thicker than RV wall
-> thicker (more muscular) as needs to contract powerfully to pump blood all round body, whereas RV only takes blood to lungs (nearby)
- atria walls are thinner than ventricle walls
-> ventricles have to push blood out of heart whereas atria just push blood short distance into ventricles - AV valves link atria to ventricles -> stop backflow of blood when ventricles contract
-> cords attach AV to ventricles to stop them being forced into atria when ventricles contract - SL valves link ventricles to pulmonary artery and aorta -> stop backflow blood into heart after ventricles contract
outline the cardiac cycle
atria systole, ventricular diastole
- atria contract, ↓ vol chambers and ↑ Pa in chambers
- pushes blood into ventricles (slight ↑ in ventricular Pa as receives blood)
ventricular systole, atria diastole
- ventricles contract, ↓ vol chambers and increasing Pa
- Pa ventricles > Pa atria so AV valves shut to prevent back flow
- Pa ventricles > Pa aorta / pulmonary artery so SL valves open and blood forced into arteries
cardiac diastole
- ventricles and atria relax
- Pa pulmonary artery / aorta > Pa heart so SL valves close to prevent back flow
- blood returns to heart and atria fill again as Pa pulmonary vein / vena cava > Pa atria
- this ↑ Pa in atria
- as ventricles relax … their Pa < Pa atria so AV valves open -> blood passively flows (not pushed by atrial contraction) into ventricles
- atria contract and repeat
