B2 - Animal Tissues, Organs And Organ Systems Flashcards

1
Q

What is the heart?

A

The heart is an organ that pumps blood around the body in a double circulatory system

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2
Q

What is the function of the right ventricle?

A

Pumps deoxygenated blood to the lungs where gas exchange takes place

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3
Q

What is the function of the left ventricle?

Why does the left ventricle have a thicker muscular wall?

A

Pumps blood around the rest of the body

LV has a thicker muscular wall because it pumps blood around the body so requires a greater force

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4
Q

What are the disadvantages of a single circulatory system, for example in fish?

A

Blood looses a lot of pressure as it passes through the gills before reaching the organs

Results in the circulation of blood to the organs being slow so the oxygen supply is delayed and not sufficient

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5
Q

Describe the double circulatory system

A

Deoxygenated blood is pumped from the heart to the lungs, where it collects oxygen

This oxygenated blood returns to the heart

The heart now pumps the oxygenated blood to the organs, where the blood transfers its oxygen to the body cells

The blood then returns back to the heart

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6
Q

What are advantages of a double circulatory system?

A

The blood passes through the heart twice, so it can travel rapidly to the body cells

This results in fast delivery of sufficient oxygen to the cells that require it for respiration

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7
Q

Describe the pattern of blood-flow through the heart

A

Blood flows into the left atrium through the pulmonary vein and the right atrium through the vena cava

The atria contract, forcing blood into the ventricles

The ventricles contract, forcing blood In the right ventricle into the pulmonary vein to be taken to the lungs, and blood in the left ventricle to the aorta to be taken around the body

As this happens, valves close to prevent the back flow of blood

The atria fill again and the cycle repeats

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8
Q

What is natural resting heart rate controlled by?

A

A group of cells located in the RIGHT ATRIUM that act as a pacemaker

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9
Q

Suggest what a doctor should do if the natural resting heart rate of a human becomes irregular

A

May use an artificial pacemaker as they correct irregularities

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10
Q

What is an artificial pacemaker?

A

Artificial pacemakers are electrical devices used to correct irregularities in the heart rate

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11
Q

What is the function of the coronary arteries?

A

Provide oxygen to the muscle cells of the heart

This oxygen is used in cellular respiration to release energy for CONTRACTION

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12
Q

What is the function of the heart valves?

A

Stop the back flow of blood into the atria when the ventricles contract

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13
Q

What is the function of the vena cava?

A

Brings in oxygenated blood from the body

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14
Q

Suggest the effects of leaky / faulty valves on an athlete

A

Leaky valves result in the back flow of blood into the atria

This results in less oxygenated blood leaving the heart

Therefore, less oxygen is supplied to body cells and working tissues

This means that less cellular respiration takes place and so less energy is released

This effects the athlete as it results in tiredness, fatigue and poor athletic ability

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15
Q

The body contains three different types of blood vessel.

What are they?

A

Arteries

Veins

Capillaries

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16
Q

What is the function of the three blood vessels?

A

Arteries transport high pressure blood away from the heart to the organs

Veins transport low-pressure blood back to the heart

Capillaries surround tissues for the exchange of substances through diffusion or active transport

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17
Q

How are arteries adapted to their function?

A

Thick muscular wall to withstand high pressure

Elastic fibres that stretch when the surge of blood passes through and recoil in between surges to keep blood moving

Small lumen

Smooth muscle

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18
Q

How are veins adapted to their function?

A

Large lumen

Thin muscular wall as it transports low-pressure blood

Contain valves to stop the back flow of blood into the atria

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19
Q

How are capillaries adapted to their function?

A

Very small lumen

One cell thick for a short diffusion distance of substances between the blood and body cells

Permeable wall, so substances can easily diffuse in and out

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20
Q

Compare the structure of arteries, capillaries and veins

A

Size of lumen: Arteries have a small lumen, whereas veins have a large lumen. Capillaries have the smallest lumen

Thickness of wall: Artery is thickest, whereas veins are thinner. Capillaries are the thinnest; one cell thick

Valves present: Veins contain valves to prevent the back flow of blood, whereas capillaries do not have valves. Arteries typically lack valves

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21
Q

What is blood?

A

Blood is a tissue consisting of plasma, in which the red blood cells, white blood cells and platelets are suspended.

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22
Q

What is the function of blood plasma?

A

A liquid substance that transports dissolved substances around the body

Examples:

  • Glucose
  • Carbon dioxide
  • Amino acids and hormones
  • Urea to the kidneys
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23
Q

What is the function of platelets?

A

Platelets are small fragments of cells that begin the process of blood clotting to stop bleeding following vessel damage

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24
Q

What is the function of white blood cells (WBCs)?

A

White blood cells form part of the immune system. Protect against infection by destroying microorganisms

Methods of defence:

  • Phagocytosis (engulfing pathogens)
  • Producing antibodies and antitoxins
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25
Q

What is the function of red blood cells? (RBCs)

A

Transport oxygen around the body to respiring cells

26
Q

What are the different blood components?

A

Plasma
Platelets
WBCs
RBCs

27
Q

How are red blood cells adapted to their function?

A

Biconcave shape. This provides a large surface area to increase rate of diffusion of oxygen molecules

No nucleus, allowing more space for the oxygen-carrying molecule haemoglobin

Contain haemoglobin. Forms oxyhemoglobin in the lungs and haemoglobin and oxygen in the organs

Thin for a short diffusion pathway

Flexible so are able to go through capillaries

28
Q

Under a microscope, how are the different blood components observed?

A
  1. Set up a light microscope (exam may use electron microscope) and a sample of blood on a slide the same way outlined in the first required practical
  2. RBCs are biconcave and red, plasma is the liquid between the components, platelets are tiny fragments (typically dots) and white blood cells are usually larger and distinct with internal structures
29
Q

How are white blood cells adapted to their function?

A

Contain a nucleus. This has DNA which encodes the instructions that the WBC has to do as part of its function

30
Q

Give three uses of donated blood in medicine

A
  • Can replace blood lost during injury
  • People are given platelets extracted from blood to help in the process of clotting
  • Proteins extracted from blood can be useful in the production of antibodies
31
Q

What are the risks of using blood products?

A
  • Many diseases can be transmitted via blood
  • In a blood transfusion, if the donated blood does not have the same blood type as the patient’s, their body’s immune system will reject it and they may die
  • However, in the UK, blood is screened for infections so the risk is extremely low (useful evaluation point)
32
Q

What is coronary heart disease?

What is its long-term effect if not treated?

A

Layers of fatty material build up inside the coronary arteries, narrowing them

This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle. As a result, there is less respiration as glucose and other substances are not transported. This causes fatigue and less energy to be released, eventually resulting in stopping heart contraction and death

33
Q

What are three methods of treating coronary heart disease: a non-communicable disease?

A

Statins (Drug)

Stents (Mechanical device)

Artificial hearts (Transplant)

34
Q

What is a statin, stent and artificial heart?

A

Statins are drugs that reduce LDL cholesterol levels, slowing down the rate of fatty material deposit

Stents are mesh tubes used to keep the coronary arteries open

Artificial hearts are mechanical devices that pump blood

35
Q

What are the advantages of using statins to treat coronary heart disease?

A

No surgery required

Easy to take

Reduces LDL cholesterol levels so directly lessens the effects of the disease

Reduce the chances of stroke

Increases the amount of HDL cholesterol

36
Q

What are the disadvantages of using statins to treat coronary heart disease?

A

Have to take the drug for life. Someone could forget to take them

Effect of statins is not instant

Negative side effects such as liver problems

37
Q

Stents are used more wisely when CHD causes a total blockage of a coronary artery.

What are the advantages of using stents?

A

Effective for many years

Blood can flow through the artery normally, so essential substances can be transported by blood plasma

Surgery is quick

38
Q

What are the disadvantages of using stents to treat CHD?

A

Intensive surgery compared to statins that are oral drugs

Does not prevent other regions of the coronary arteries from narrowing (Good evaluation point)

Risk of infection and blood clotting

39
Q

What is heart failure?

A

When the heart cannot pump sufficient blood around the body

40
Q

What are the advantages of using artificial hearts to treat CHD?

A

Keeps the patient alive whilst waiting for a donated heart transplant

Allows the heart to rest as an aid to recovery

41
Q

What are the disadvantages of using artificial hearts to treat CHD?

A

Risk of blood clotting

Parts of the heart could wear out, or the electrical motor could fall

Surgery can lead to bleeding or infection

42
Q

What are the disadvantages of donated hearts?

A

Not enough to treat every patient with cardiovascular disease

May have to take drugs to stop the donated heart from being rejected by the immune system

43
Q

What is health?

A

Health is the state of physical and mental well-being

44
Q

What factors affect health?

A

Diet

Stress

Life situations

Diseases - both communicable and non-communicable

45
Q

Describe how different types of diseases may interact

A

Defects in the immune system mean that an individual is more likely to suffer from infectious diseases

Viruses in cells can be the trigger for cancers

Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma

Severe physical ill health can lead to depression and mental illness

46
Q

What is epidemiology?

A

Studying the patterns of disease to determine risk factors

47
Q

What are risk factors?

A

Factors that are linked to an increased chance of developing a particular disease

48
Q

Risk factors can be…

A

Aspects of a person’s lifestyle (sedentary)

Substances in the person’s body or environment

49
Q

What is a causal mechanism?

A

The processes or pathways through which an outcome is brought into being

50
Q

A causal mechanism has been proven for some risk factors, but not in others.

What are some of these?

A

Poor diet, smoking and lack of exercise -> risk factors for cardiovascular disease

Obesity -> risk factor for Type 2 diabetes

Alcohol -> risk factor for poor liver and brain function

Smoking -> risk factor for lung disease and cancer

Carcinogens, including ionising radiation -> risk factor for cancers

51
Q

What are the human and financial costs of non-communicable diseases to an individual, a local community, a nation or globally?

A

Cost to health care services such as the NHS for researching and treating

Families may have to move or adapt their home to help a family member

Families’ income may be reduced if the provider has a non-communicable disease. This will impact the entire household and the economy

52
Q

Explain the effect of lifestyle factors including diet on the incidence of non-communicable diseases at local, national and global levels

A

A diet high in fat and low in vegetables increases LDL cholesterol. This in turn increases fatty deposits in the arteries and risks for CHD

A diet high in salt can increase blood pressure, increasing risk for cardiovascular diseases

53
Q

Explain the effect of lifestyle factors including smoking on the incidence of non-communicable diseases at local, national and global levels

A

Cigarettes contain carcinogens that can result in cancer. Smoking also increases the risk of other lung diseases such as EMPHYSEMA

Smoking while pregnant can harm an unborn baby. This increases the risk of miscarriage and premature birth. Can also increase the risk of a baby having low body mass

54
Q

Explain the effect of lifestyle factors including alcohol on the incidence of non-communicable diseases at local, national and global levels.

A

Drinking alcohol or smoking while pregnant increases the risk of foetal alcohol syndrome as smoke contains carbon monoxide so blood carries less oxygen to foetus. Results in these children having learning difficulties and mental/physical issues

Also increases risk of liver cirrhosis and cancer. Also increases the risk of poor cognition, including memory loss and addiction

55
Q

Explain how the human circulatory system is adapted to supply oxygen to the tissues and remove waste products from tissues

A
  • Double circulatory system which means it has higher blood pressure and a greater flow of blood to the tissues
  • Oxygen is carried by RBCs, which contain haemoglobin to bind oxygen
  • Arteries carry oxygenated blood to tissues where capillaries deliver oxygen to cells for respiration and energy release
  • Capillaries have a large surface area to maximise gas exchange
  • Waste products removed such as CO2 which diffuse from cells into the blood plasma
  • Blood goes back to the heart in veins which have valves to prevent back flow
56
Q

Why do the ventricles contract only after the atria contract?

A

Needs to be time for the ventricle to fill with blood
Otherwise the ventricles will contract while empty

57
Q

Give two differences in the composition of the blood between blood taken from an artery in the leg and blood taken from a vein in the leg

A

More oxygen
More glucose
More amino acids

Less carbon dioxide
Less lactic acid

58
Q

Suggest when artificial hearts are most likely to be used instead of a natural heart donor

A
59
Q

Suggest why men and women commonly have different types of cancers

A
60
Q

Explain how changes to an obese person’s lifestyle can help them lose weight

A
61
Q

[Graph of a possible risk factor with the number of people diagnosed with a disease shown to be a positive correlation]

Evaluate whether the data shows that the factor is a risk factor for the disease

A

Appears to be a link, but correlation does not indicate causation

More evidence is needed

Could be other factors interacting linked to the disease

Always look at: source of data, period of time, if correlation is constant and the size of the population. Provide a judgement with evaluation questions

62
Q

Cirrhosis of the liver leads to liver failure

Describe the effects of liver failure on the human body (4)

A

No bile made in the liver —> Fats not emulsified, so surface area of lipids not increased. pH of small intestine will not be alkaline so enzymes will not work effectively to digest food. As a result, the person may lose weight

Lactic acid not broken down/oxidised —> accumulation of lactic acid in the blood which is toxic. Oxygen debt is prolonged so there will be muscle pain and fatigue

Proteins/amino Acids will not be broken down in the liver. Amino acids not deaminated. Amino acids not made into urea so are accumulated in the blood

Liver will not remove other toxins such as alcohol —> toxins accumulate in the blood so the person may suffer from pain and portal hypertension may occur

Glycogen stores will not be formed —> cannot control blood glucose, so hyperglycaemia may occur