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Higher Biology Unit 2: Physiology & Health > Cardiovascular disease, obesity and diabetes > Flashcards

Cardiovascular disease, obesity and diabetes Flashcards

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1
Q

give 5 factors that would increase the risk of developing CVD?

A 
lack of physical activity
diet high in saturated fat/ salt
obesity 
smoking 
family history (genetic factors)
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2
Q

What is atherosclerosis?

A

the build up of plaques within the wall of artery, underneath the internal endothelial lining.

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3
Q

What are the plaques known as?

A

atheromas

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4
Q

What does an atheroma begin as?

A

a ‘‘fatty streak’’ that progresses over time. Cholesterol, calcium and fibrous material accumulate around the streak and cause it to grow

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5
Q

What does the growth of the atheroma cause?

A

it to encroach into the lumen of the artery, thereby narrowing it.

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6
Q

What problems are caused by the narrowing of the lumen in the artery?

A

Blood flow becomes occluded (blocked) and the tissues served by this artery begin to receive a limited supply of blood. The blockage also increases arterial blood pressure as the build-up of blood continues

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7
Q

What do the deposits of calcium surrounding the atheroma result in?

A

the hardening of the artery and the loss of elasticity can further increase blood pressure

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8
Q

What does the body’s immune system do to the damaged site of the vessel?

A

different immune cells (monocytes, macrophages and different inflammatory markers) are attracted to the damaged site and a fibrous cap of different cell types forms over the top of the atheroma which stabilizes it.

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9
Q

If an atheroma forms in a coronary artery what does it lead to?

A

an increase in the risk of mycardial infarction or stroke.

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10
Q

What is angina?

A

a condition that occurs in response to atherosclerosis in the coronary vessels where the patient experiences pain when the heart is stressed (during exercise)

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11
Q

What is it known as if atherosclerosis occurs in vessels at the extremities of the body?

A

peripheral vascular disease

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12
Q

What are blood clots designed to do?

A

prevent excessive blood loss

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13
Q

Describe the steps that lead to the formation of a blood clot?

A

Damage to endothelial cells leads to the production of molecules known as clotting factors (e.g. vitamin K)
These promote the conversion of inactive enzyme prothrombin to the active enzyme thrombin.
Thrombin promotes the conversion of soluble plasma protein fibrinogen to insoluble fibrin. Fibrin forms a meshwork which forms a clot, seals the wounds and provides a scaffold for the formation of scar tissue. (it also forms a key part of the cap which develops over the top of the athermona)
The action of these clotting factors attracts platelets which adhere to the structures they create and ultimately form a blood clot

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14
Q

What is name given to the process where a blood clot (thrombus) is formed in a vessel usually resulting from an atheroma bursting through the endothelium?

A

thrombosis

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15
Q

If the thrombus becomes dislodged what is it known as?

A

embolus

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16
Q

What can an embolus?

A

travel in the blood until it blocks a smaller vessel. The narrowing and blocking of these vessels (occlusion) prevents an adequate supply of blood and oxygen getting to the tissues which leads to them becoming damaged or dying.

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17
Q

What does an embolus blocking a coronary atery do?

A

limit blood flow to cardiac muscle and results in mycoardial infarction

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18
Q

What does an embolus lodged in an artery in the brain lead to?

A

stroke

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19
Q

How does an antiplatelet drug work?

A

a form of pharmaceutical medication that interferes with the formation of a blood clot by inhibiting the sticking together of platelets. Therefore, antiplatelet drugs are used to prevent the formation of a thrombus that could coronary thrombosis or a stroke in people who are at high risk of developing the condition e.g. aspirin

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20
Q

How do anticoagulation drugs work?

A

used in the treatment of thrombotic disorders such as deep vein thrombosis and pulmonary embolism. An anticoagulant differs from an antiplatelet drug in that leads to fibrin production e.g. warfarin

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21
Q

What is another anticoagulant?

A

prevents vitamin K from carrying out its function in the pathway. However, excessive depletion of vitamin K leads to increased risk of hardening of arteries e.g. Heparin

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22
Q

In terms of peripheral vascular disease, where does atherosclerosis frequently occur?

A

in the vessels of the leg with sufferers experiencing pain and discomfort, particularly during exercise, due to an inadequate supply of oxygen to respiring tissue. This pain is commonly known in the medical profession as claudication

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23
Q

What does deep vein thrombosis describe?

A

the formation of a thrombus in the peripheral blood vessels, most commonly in the legs. Due to this blockage, blood can accumulate in these veins again resulting in discomfort in the part of the body the thrombus has formed in. More superficial veins (close to the surface) can become swollen and visible as raised under the skin as blood is diverted around the thrombus.

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24
Q

How can the risk of developing DVT increase?

A

during prolonged periods of inactivity. For instance, individuals who are immobile (e.g. bed ridden patients) have a decreased return of blood to their heart (venous return) as they don’t have as many contractions of muscles around the vein. As a result, blood can accumulate and a thrombus can form. This can also be the case to a lesser extent during a long distance flight

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25
Q

What is a pulmonary embolism?

A

when an embolus becomes lodged in a branch of the pulmonary artery. The lack of blood reaching the lungs can cause chest pains and potentially loss of consciousness or even sudden death

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26
Q

What is cholesterol?

A

an essential substance synthesised in liver cells which is a key component in cell membranes as well as being the basis of steroid hormones. It is also a component of saturated fat consumed in the diet.

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27
Q

How is cholesterol transported?

A

by compounds called lipoproteins (HDL and LDL)

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28
Q

Where does low density lipoproteins transport cholesterol?

A

from the liver to body cells where they attach to receptors on the cell’s surface to allow the lipid to enter and be used as a substrate.

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29
Q

What happens when body cells become full of cholesterol?

A

the process of negative feedback inhibits the production of these receptors. This leads to decreased sensitivity to LDL-cholesterol and ultimately it accumulates in the blood

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30
Q

What does excess LD-cholesterol place individual at a higher risk of developing?

A

atherosclerosis

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31
Q

What does high density lipoprotein act as?

A

a ‘‘scavenger’’ circulating the body picking up excess LDL-cholesterol and carrying it to the liver. This safety mechanism should prevent the accumulation of LDL-cholesterol if both are in appropriate balance

32
Q

What is measuring the total blood cholesterol of an individual not indicative of?

A

their health or risk of heart disease.

33
Q

What is a healthy ‘‘lipid profile’’ ?

A

high levels of HDL-cholesterol and low levels of LDL (high HDL:LDL ratio)

34
Q

How could you achieve high levels of HDL-cholesterol and low levels of LDL (highe HDL:LDL ratio)?

A

an active lifestyle with an appropriate diet

35
Q

Describe 2 factors which lead to an accumulation of LDL in the blood?

A

eating a diet rich in saturated fat throughout life

suffers an inherited condition called familial hypercholesteroaemia

36
Q

What are statins ?

A

a group of medication designed to lower the levels of LDL cholesterol circulating in the blood.

37
Q

How statins work?(2)

A

They inhibit an enzyme essential for the synthesis of cholesterol by liver cells. (HMG-CoA reductase promotes the first step in a long chain of biochemical reactions that lead to the production of cholesterol.) The statins act as competitive inhibitors.

Also act by increasing the number of LDL receptors made by liver cells . These receptors bring about a reduction in the level of ‘bad cholesterol’ by removing some molecules of LDL-cholesterol from the bloodstream

38
Q

What is familial hypercholesteroaemia?

A

an inherited condition which results in high levels of circulating LDL-cholesterol. This is an autosomal dominant condition where the mutated gene causes a decrease in LDL-receptor density and impaired function in the receptors that are present.

39
Q

What can familial hypercholesteroaemia lead to?

A

strong patterns of heart disease and other associated metabolic disorders running through families

40
Q

What can identification of the mutated gene for familial hypercholesteroaemia allow?

A

preventative treatment and lifestyle modification rather than treatment of the condition itself

41
Q

Describe 4 features that are typical of an autosomal dominant disorder?

A

the trait appears in every generation
each sufferer has an affected parent
males and females are affected approximately equally
when a branch of the family doesnt express the trait, the trait fails to reappear in future generations of that branch

42
Q

What do sufferers of diabetes who have elevated blood glucose levels at higher risk of having?

A

cardiovascular disease and strokes

43
Q

Why are diabetics at higher risk of having cardiovascular disease and strokes?

A

the accumulation of excess glucose in the endothelial cells lining the inner surface of blood cells causes them to swell and possibly burst. The walls of these small vessels become less responsive to changes in blood flow and may fail to dilate properly, leading to an increase in blood pressure. The impaired endothelial function means that tissues can become damages as they do not receive an adequate oxygen supply

44
Q

What is glucose required for ?

A

the regeneration of ATP by respiration

45
Q

How is glucose consumed?

A

in the diet

46
Q

What does the need for energy mean?

A

that glucose must always be available to meet the requirements of respiring cells

47
Q

The requirements (glucose) change depending on the demands placed on the body. As a result what does the body use?

A

a negative feedback mechanism to ensure an appropriate concentration of glucose in the blood is maintained

48
Q

What happens when glucose is not required?

A

it is stored in the liver or muscle in the form of the complex carbohydrate glycogen. This acts as a ‘‘pool’’ of glucose which can add glucose to of take glucose from the blood whenever it is required.

49
Q

When would there be a rise in blood glucose level?

A

after a meal

50
Q

What detects the rise in blood glucose and what does this cause?

A

detected by receptor cells in the pancreas, stimulating the release of the hormone insulin from beta cells in the pancreas. Insulin travels in the blood to the liver and allows an enzyme in the liver to convert the excess glucose to glycogen thereby reducing blood glucose levels to ‘‘normal’’

51
Q

What detects a drop in blood glucose concentration and what does this cause?

A

receptors in the pancreas detect this change and release another hormone, glucagon. This has the opposite effect of insulin and causes the breakdown of glycogen to glucose to be released into the bloodstream to again return it to ‘‘normal’’ levels.

52
Q

What do insulin and glucagon work together antagonistically to do?

A

maintain the homeostasis of blood glucose

53
Q

What can certain circumstances e.g. during exercise or an emergency require?

A

the rapid release of glucose to be available for ATP production.

54
Q

How would the body achieve a rapid release of glucose to be available for ATP production?

A

through the release of the hormone adrenaline from the adrenal glands which over rides normal homeostatic control and promotes the rapid breakdown of glycogen to glucose by stimulating glucagon secretion and inhibiting insulin secretion. After this period has passed, levels of adrenaline are reduced and normal control of glucose can continue

55
Q

What is diabetes?

A

the condition caused by an inability to maintain a normal blood glucose concentration

56
Q

At rest, what should blood glucose be maintain at ?

A

5 mmol/l

57
Q

In individuals with uncontrolled diabetes, what can their blood glucose level rise to?

A

anywhere between 10 and 40 mmol/l

58
Q

What are the 2 types of diabetes?

A

type 1

type 2

59
Q

Describe type 1 diabetes?

A

sufferers will usually be diagnosed when they are still an infant.
It is a result of the inability of the pancreas to produce sufficient volumes of insulin to correct any increase in blood glucose.

60
Q

What treatment is given to sufferers of type 1 diabetes?

A

insulin injections prior to meals (work immediately) to maintain homeostasis and should follow relatively strict dietary guidelines. This treatment works as body cells and liver cells are still sensitive to the action of insulin and respond accordingly to its presence

61
Q

What is the cause of type 1 diabetes?

A

it varies and may never be known by a patient although there is frequently likely to be a strong genetic component

62
Q

Describe type 2 diabetes?

A

traditionally known as ‘‘adult-onset diabetes’’ due to its prevalence in an older population. Although this remains broadly true, there has been a significant rise in its incidence in a younger population.
Insulin is still produced.
However, the cells of the body and liver are not sensitive to it (due to decrease in insulin receptors) and are resistant to its effects, leaving blood glucose levels elevated

63
Q

What is the cause of type 2 diabetes?

A

obesity, inactivity and poor lifestyle choices

64
Q

What treatment is recommended to sufferers of type 2 diabetes?

A

alteration of lifestyle and weight loss although failure to correct over a long period of time may result in a progression to a condition more similar to type 1 diabetes.

65
Q

What effect does the high concentration of glucose in the blood have on the kidneys?

A

they are unable to reabsorb all of it to from the filtrate. This results in the presence of glucose in the urine which can be detected from a basic urine sample and use of a glucose indicator

66
Q

What test can be carried out to assess the ability of a body to manage blood glucose levels?

A

glucose tolerance test

67
Q

Describe how you would carry out a glucose tolerance test?

A

a patient fasts for around 8-10 hours and their resting blood glucose concentration is taken before they consume a glucose drink with a known glucose concentration. Their blood glucose is then monitored at intervals over 2.5 hours and their results recorded
to show how the body managed the glucose ingested.

68
Q

In a glucose tolerance curve what will the medical professional analyse?

A

the resting blood glucose after fasting
how long blood glucose continued to rise for after ingestion
how long it takes for it to fall and whether it reaches resting levels within the 2.5 hours

69
Q

What is obesity characterised by?

A

the presence of excess body fat in relation to the proportion of lean body mass

70
Q

What is a common measure of obesity?

A

body mass index

71
Q

How do you calculate BMI?

A

body mass (kg)/height’2 (m)

72
Q

What is the BMI of an obsese individual?

A

> 30

73
Q

Explain the accuracy of BMI as a measurement of obesity?

A

limited by the fact it doesnt take into account whether an individual has a high mass due to a high lean muscle of mass or due to a high percentage of body fat. Despite this, it remains a good measure for the majority of the population

74
Q

Give some causes of obesity?

A

diet high in saturated fat, refined carbohydrate and sugar

lack of physical activity

75
Q

How can the percentage of the body which composed of fat can be calculated?

A

skin fold thickness
densitometry
bioelectrical impedance analysis

76
Q

Give examples of lifestyle factors which can contribute to an obese individual reducing their risk to conditions such as cardiovascular disease and type 2 diabetes?

A

An appropriate diet which limits consumption of saturated fat, ‘‘artificial’’ foods and highly refined carbohydrates and sugars which are too readily absorbed by the digestive system with minimal effort and little energy expended
An increase in physical activity which expends a significant proportion of the energy consumed. Current guidelines suggests this should be a MINIMUM of 30 minutes of moderate exercise >3 days per week. This will maintain energy balance and give a number of health benefits. Exercise has been found to reduce the incidence and symptoms of type 2 diabetes even without weight loss

Higher Biology Unit 2: Physiology & Health (7 decks)

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