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Bio AS paper 1 > The heart, circulation and CVD > Flashcards

The heart, circulation and CVD Flashcards

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1
Q

Explain the difference between an open and closed circulatory system

A

Open circulatory system - No blood vessels, no blood but have haemolymph. Works via diffusion

Closed circulatory system - Blood vessels carry blood around the body. This blood has been pumped by the heart.

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2
Q

Why is a circulatory system required?

A

To transport blood around an organism. Diffusion is limited. Circulatory system overcomes this

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3
Q

Features of Arteries

A
  • Carry oxygenated blood away from the heart (except pulmonary artery)
    -Small lumen to maintain high blood pressure
    -Smooth inner endothelial layer (smooth surface means less resistance to blood flow)
    -Thick layer of smooth muscle (contract and relax to contract and dilate blood vessels-controlling their diameter) and elastins (stretch and recoil)
    -lots of collagen fibres for strength and support
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4
Q

What are advantages of having a double circulatory system?

A

Blood comes to heart twice, the seconds time it is pumped it is oxygen rich
This means oxygen rich blood can pumped to organs and muscles.

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5
Q

Explain why large organisms such as giraffes need a mass transport system (4 marks)

A

Giraffes are very large mammals meaning they need a mass transport system to transport blood to muscles and organs. Giraffes have a small SA:Vol ratio meaning they cant rely on diffusion. The giraffe needs blood vessels like arteries to pressurise blood so the blood can travel up the long neck.
The double circulatory system removes carbon dioxide

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6
Q

Features of Capillaries

A

-Very small
-Narrow lumen
-Thin endothelium (one cell thick allows for fast rate of diffusion as distance is short)
-Blood travels slowly so that oxygen can diffuse properly

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7
Q

Features of Veins

A

-Carry deoxygenated blood into the heart (except the pulmonary vein)
-Have valves to prevent backflow of blood due to low pressure
-Large lumento maintain lower pressures
-Thinner layer of muscle and elastic fibres
-Reduced collagen fibres

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8
Q

Explain why muscle in left side of the hart is thicker than muscle in the right side of the heart

A

-Muscle in the left side of the heart pumps blood around body (via aorta). This blood needs to travel far so the muscles in left side of heart contract harder to produce a greater force so blood travels further around the body

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9
Q

Explain atrial systole

A

Atria contract causing atrioventricular valves to open and blood flows into the ventricles

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10
Q

In arteries, why is the endothelium folded?

A

So the arteries can stretch.

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11
Q

During the development of the mammalian heart, there is a hole between the left ventricle and the right ventricle.
This hole usually becomes sealed before the mammal is born. If it is not sealed, the mammal will become easily tired due to a lack of energy.
Explain why a mammal born with a hole between the two ventricles will have these symptoms.

A

Less oxygen for aerobic respiration.

Deoxygenated blood mixes with oxygenated blood

Reduces concentration of oxygen in the blood circulating round the body

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12
Q

Daphnia can be used to investigate the effects of caffeine on heart rate.
Devise a procedure to compare the effects of decaffeinated coffee and regular coffee on the heart rate of Daphnia.
(4)

A

An answer which makes reference to the following:

· Daphnia (immobilised) on (cavity) slide (1)
. acclimatisation time in {control / dopamine /dopamine and caffeine} solution (1)
. use of concentrations from graph (1)
. suitable method for counting and recording heart rate (1)
· use Daphnia of same {species / age / sex / size} (1)
. repeats and calculation of {mean / SD} (1)

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13
Q

Explain how pressure differences in the heart ensure efficient pumping of the blood into the arteries.

A

Pressure increases in the ventricles.
There is a greater pressure in ventricles than there is in the arteries causing the atrioventricular valves to close forcing blood into the arteries

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14
Q

State the type of blood vessel that has no collagen in its wall

A

Capillary

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15
Q

Explain why high blood pressure can increase the risk of developing cardiovascular disease (CVD).

A

High blood pressure causes damage to the endothelium of the arteries.

Plaque develops and narrows the lumen of artery causing blood to travel at a higher pressure

Narrow lumen means less oxygen in the blood can reach cardiac muscle for respiration

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16
Q

Explain how the diet of a person could affect the development of CVD.

A

A higher salt intake increases blood pressure which causes damage to endothelium of the artery.
High intake of cholesterol and saturated fats.

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17
Q

Explain how atherosclerosis can result in damage to the heart (3 marks)

A

Atherosclerosis causes the arteries to become narrower due to build up of an atheroma, this can create a blockage meaning less oxygen in the blood reaches the heart muscle for aerobic respiration.

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18
Q

Describe how very high blood pressure could result in atherosclerosis.

A

High blood pressure damages endothelium layer causing an inflammatory response. Build up of white blood cells/cholesterol leads to formation of an atheroma. Atheroma forms a plaque as calcium builds up. This hardens the atheroma and narrows the lumen

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19
Q

Compare and contrast the heart and circulatory system of a snake with that of a human (4 marks).

A

Similarities:
-Both have a double circulatory system
-Both have 2 atria, veins, arteries and capillaries
Differences:
-Snake heart doesn’t have a septum whereas human heart does.
-In snakes, oxygenated and deoxygenated blood mix

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20
Q

What are the factors affecting the incidence of coronary heart disease?

A

Increasing age (Arteries become less elastic with age)
Genetics (genetically predisposed to high blood pressure)
Diet (Diet can increase cholesterol)
Gender (oestrogen makes arteries more elastic)
High blood pressure (Damages endothelium)
Obesity (Increases blood pressure)
Physical activity (Increases obesity risk)
Smoking (nicotine narrows arteries)

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21
Q

Provide some treatments of CVD

A

-Anticoagulants reduce the risk of clot formation.

-Statins, which reduce blood cholesterol levels by blocking the enzyme which produces cholesterol in the liver.

-Antihypertensives, which reduce blood pressure.

-Beta blockers, which reduce the frequency of heart contractions and make them less powerful by blocking response of heart to hormones. However, taking beta blockers might increase risk of diabetes .

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22
Q

Which drug reduces blood pressure?

A

Anti hypertensives

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23
Q

Explain how atherosclerosis can result in damage to heart muscle.

A

Narrows the lumen of coronary arteries
This reduces blood flow of oxygen to cardiac muscle which reduces respiration

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24
Q

Why does blood need to clot?

A

Prevent blood loss
Prevent entry of harmful bacteria
Provides a framework for repair

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25
Q

Explain the process of blood clotting

A

Platelets release thromboplastin in response to damage
Causes prothrombin to change to its original form, thrombin
Turns soluble fibrinogen into fibrin, forming a mesh that traps blood cells

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26
Q

How can blood clots be detrimental to health?

A

Restricts blood flow meaning tissues dont get the oxygen supply needed

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27
Q

Explain ventricular systole.

A

contraction of the ventricles causes atrioventricular valves to close and semi lunar valves to open, allowing blood from left ventricle to leave via aorta and blood from right ventricle to leave via pulmonary artery

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28
Q

Explain cardiac diastole

A

Atria and ventricles relax and pressure inside the heart chambers decreases causing semi lunar valves in aorta and pulmonary artery to close, preventing backflow of blood.

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29
Q

3 treatments of CVD

A

Antihypertensives
Statins
Platelet inhibitors

30
Q

Benefit and risk of using antihypertensives as medication

A

+ Reduces risk of kidney failure and lowers blood pressure
- Can cause dizziness and nausea

31
Q

Benefits and risks of using statins as medication

A

+ Lowers cholesterol
- Nausea, inflammation and constipation

32
Q

Benefits and risks of anticoagulants

A

+ Prevents blood from clotting
- Taking too much can lead to uncontrolled bleeding

33
Q

Benefits and risks of using beta blockers as medication

A

+ Reduces frequency of heart contractions
- Increased risk of diabetes

34
Q

Discuss the benefits and risks of using antihypertensives, statins and anticoagulants to treat cardiovascular disease. (6 marks)

A

Antihypertensives lower blood pressure. This leads to lower stroke chances as lower blood pressure reduces damage of blood vessel to the brain. However, they have risks such as low blood pressure and fainting.

Statins decrease the incidence of strokes. Statins lower cholesterol in the blood by blocking an enzyme which produces cholesterol in the liver. More blood can be pumped around the body due to less blockages in the arteries. However, statins can cause inflammation, nausea.

Anticoagulants prevent blood from clotting however they can lead to uncontrolled bleeding if they are not taken in the correct dosages. Reducing the number of blood clots reduces the number of strokes as blood can travel better through blood vessels to the brain

35
Q

Relate the structure of the hearts chambers to their functions

A

Atria- Thin walled and elastic so they can stretch when filled with blood

Ventricles- Thick muscular walls pump blood at high pressure. The left ventricle is thicker than the right ventricle because it pumps blood to the whole body

36
Q

What are the 2 types of cholesterol

A

LDL- low density lipoprotein, Accumulates in blood and doesn’t get taken into cells, stays in blood and accumulates

HDL - High density lipoprotein, Goes back to liver to be broken down

37
Q

Explain how the structure of a vein relates to its function (4 marks)

A

Veins have valves to prevent the backflow of blood because blood travels at low pressures.

Veins have thinner muscle wall as blood doesn’t travel at high pressures.

Veins have a smooth endothelium meaning blood can travel with less friction.

Veins have a large lumen meaning blood travels with less friction

38
Q

Explain the function of the elastic fibres in the aorta (2 marks)

A

Allows stretch and recoil in order to maintain blood pressure

39
Q

Explain the function of the semilunar valve in the aorta (2 marks)

A

Opens as blood pumped into aorta (1)
Valve closes {during diastole / start of diastole} (1)
Prevents backflow of blood (from aorta back) into the left ventricle (1)

40
Q

Which of the following is another risk factor for CVD? (1)

A) High blood pressure
B) Low blood cholesterol
C) Low salt intake
D) Using statins

A

A - high blood pressure

41
Q

It is possible to reduce the risk of CVD by taking medication or changing diet.

Explain the role of antihypertensive drugs in reducing the risk of atherosclerosis (4 marks)

A

-Antihypertensive drugs lower blood pressure (1)
-Lower blood pressure reduces risk of damage to endothelium of the artery (1)
-Reduced risk of inflammatory response (1)
-Rreduced risk of { atheroma / plaque } formation (1)

42
Q

Explain how the structure of an artery wall is adapted both to withstand and to maintain high blood pressure (3)

A

-(more) collagen provides strength (to withstand pressure) (1)
-(contraction of) muscle allows constriction (of lumen / artery) (1)
-Elastic fibres allow (stretch and) {recoil / lumen to return to original size} (1)

43
Q

Explain how atherosclerosis in one part of an artery could increase the likelihood of it developing in another part of the same artery (2)

A

-{plaques / atherosclerosis} narrow the lumen (1)
-Increasing blood pressure (further) (1)

44
Q

Describe how nucleotides join together to form DNA (2)

A

-Condensation reaction (1)
-Phosphodiester bonds (1)
-DNA polymerase (1)

45
Q

Explain the effect that a diet high in salt could have on a person’s risk of developing cardiovascular disease (5)

A

-Diet high in salt increases risk of CVD (1)
-(high salt intake causes) higher blood pressure (1)
-(which increases risk of) { damage to endothelium of artery / atherosclerosis } (1)
-(therefore increases risk of) inflammatory response (1)
-(leading to increased risk of) { atheroma / plaque formation } (1)
-Narrowing of arteries { increases risk of blood clots / increases blood pressure / reduces blood flow to cardiac muscle } (1)

46
Q

A variety of drugs can be used to reduce blood pressure. These drugs may cause side effects in some people.

State two possible side effects of taking drugs to reduce blood pressure (2)

A

-Nausea (1)
-Muscle cramps (1)
-Dizziness / fainting / hypotension (1)
-Kidney failure (1)

47
Q

High levels of sugars, such as fructose, in processed food could be contributing to this increase.

Explain why high levels of sugars in a person’s diet could lead to obesity (3)

A

-Energy intake higher than energy output (1)
-(excess) {energy / sugars} can be {stored as / converted to} fat (1)
-Leading to weight gain (greater than overweight) (1)
-Obesity as indicated by a {BMI above 30 / waist-hip ratio greater than 0.85 in women or 1.0 for men} (1)

48
Q

Explain how a blood clot could form in a blood vessel (4)

A

-Collagen is exposed when wall of blood vessel is damaged (1)

-Leading to release of thromboplastin (1)

-(thromboplastin catalyses) conversion of prothrombin to thrombin (1)

-(thrombin catalyses) conversion of fibrinogen to fibrin (1)

-Fibrin forms a mesh of fibres and traps (red) blood cells (to form a clot) (1)

49
Q

Diet is one factor that affects the development of CVD.
Explain how the diet of a person could affect the development of CVD (4)

A
  • High(er) salt intake (1)
  • This increases blood pressure (1)
  • High blood pressure causes damage to endothelium (of artery) (1)
  • High intake of {cholesterol / saturated fat} (1)
  • High {LDL’s / saturated fat} linked to {atheroma / plaque formation} (1)
50
Q

Explain how blood tests and obesity indicators can be used to collect data to predict the risk of developing CVD (4)

A
  • Blood test to measure {HDL and LDL / cholesterol} levels
  • Higher HDL:LDL decreases risk / high cholesterol increases risk
  • Measurement of {height and mass / waist and hip size} / calculation of {BMI / waist: hip}
  • {BMI above 30 / waist: hip above 1} increases risk
51
Q

Variables relating to the caffeine solution and the ghost shrimps should be controlled.
State and justify two variables that should have been controlled in this investigation.
(4)

A

Variable relating to the caffeine solution
- {temperature / aeration} of solution / acclimatisation
time (1)
-If there isn’t enough acclimatisation time this can lead to there being no affect of caffeine on shrimp, giving inaccurate results

Variable relating to the ghost shrimps
* Same {sex / size / age} of ghost shrimp (1)
* So caffeine would affect the ghost shrimp equally / to produce more valid results

52
Q

Explain how blood tests and obesity indicators can be used to collect data to predict the risk of developing CVD (4)

A

-Blood tests to measure cholesterol levels
-Higher HDL:LDL decreases risk/ high cholesterol increases risk
-Measurement of height and mass/ waist and hip size/ calculation of BMI
- BMI above 30 increases risk

53
Q

Explain why platelet inhibitors would reduce the risk of a heart attack (2)

A
  • Platelet inhibitors reduce the risk of blood clots forming
  • Therefore less likely that blood flow to heart arteries will be blocked
54
Q

Explain the effect that a diet high in salt could have on a person’s risk of developing CVD (5)

A

-Diet high in salt increases risk of CVD
-High salt intake causes higher blood pressure
-This increases risk of damage to endothelium of artery/atherosclerosis
-Therefore increases risk of inflammatory response
-Increased risk of atheroma/plaque formation
-Narrowing of arteries increases risk of blood clots/increases blood pressure/reduces blood flow to cardiac muscle

55
Q

State two possible side effects of taking drugs to reduce blood pressure (2)

A

Nausea
muscle cramps
dizziness/fainting
kidney failure

56
Q

Describe the role of LDLs in the development of atherosclerosis (3)

A
  • LDL carry cholesterol in the blood
  • Cholesterol is deposited to form atheroma
  • In the endothelium of the artery
57
Q

Explain how atherosclerosis can lead to damage to heart muscle (3)

A

-Narrowing of lumen of coronary arteries
-Which reduces blood flow to the cardiac muscle
-Which reduces aerobic respiration

58
Q

Explain how atherosclerosis in one part of an artery could increase the likelihood of it developing in another part of the same artery

A
  • Atherosclerosis narrow the lumen
  • increasing blood pressure further
59
Q

Explain the role of antihypertensive drugs in reducing the risk of atherosclerosis

A

-Antihypertensive drugs lower blood pressure
-Lower blood pressure reduces risk of damage to endothelium of the artery
-Reduced risk of inflammatory response
- Reduced risk of atheroma formation

60
Q

Explain the effect that large quantities of LDL would have in blood cholesterol levels (3)

A
  • Increased blood cholesterol
  • Because the triglyceride is saturated
  • LDLs transport cholesterol
61
Q

Explain how a blood clot could form in a blood vessel (4)

A
  • Collagen is exposed when wall of blood vessel is damaged
  • Leading to release of thromboplastin
  • Thromboplastin catalyses conversion of prothrombin to thrombin
  • Thrombin catalyses conversion of fibrinogen to fibrin
  • Fibrin forms a mesh of fibres and traps red blood cells to forma clot
62
Q

Describe the role of thrombin in blood clotting (3)

A
  • Thrombin is an enzyme
  • Which catalyses conversion of fibrinogen to fibrin
  • A mesh of fibrin traps red blood cells to form a clot
63
Q

Explain why blood clot formation in capillaries could cause tissues to die (2)

A

-Lumen of capillaries is blocked
- Preventing oxygen supply to tissues or cells

64
Q

A pathogenic strain of E.coli produces a toxin that reduces blood platelet concentration

Explain how an E.coli infection increases the time taken for blood clot to form (3)

A
  • Less thromboplastin released from fewer platelets
  • So less prothrombin converted to thrombin
  • Meaning less fibrinogen converted to fibrin
  • Fewer platelets to be trapped in the fibrin mesh
65
Q

Explain the function of the semilunar valve in the aorta (2)

A
  • Semi-lunar opens as blood is pumped into aorta
  • Valve closes during diastole to prevent back flow of blood into the left ventricle
66
Q

Explain the function of elastic fibres in the aorta (2)

A
  • Allows stretch and recoil of aorta
  • In order to maintain blood pressure
67
Q

Explain how the structure of a vein relates to its function (4)

A
  • Large lumen to reduce resistance to blood flow back to the heart
  • Valves prevent back flow of blood
  • Thin layer of muscular tissue/elastic fibres in the wall to maintain blood pressure
  • Smooth endothelium to reduce resistance to blood flow
68
Q

Explain how the structure of an artery wall is adapted both to withstand and to maintain high blood pressure (3)

A
  • Collagen provides strength to withstand pressure
  • Contraction of muscle allows constriction of lumen
  • Elastic fibres allow stretch and recoil of lumen to return to original size
69
Q

Explain why there is a difference in the thickness of the walls of the aorta and the vena cava (3)

A
  • The aorta contains more muscle tissue in order to maintain pressure
  • It also contains more collagen so it can withstand high pressure
  • As well as more elastic tissue so that it can recoil.
70
Q

Explain why the location of a blood clot would affect the oxygen-saturation of blood leaving the left lung (3)

A

-If blood clot is at the bronchi, it will result in the largest reduction in blood-oxygen concentration
-As it would result in reduced blood flow into the lung
-Which would result in reduced gas exchange
-Fewer red blood cells can be oxygenated

Bio AS paper 1 (4 decks)

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