B2 - Animal Tissues, Organs And Organ Systems

Question 1

What is the heart?

Answer 1

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

Question 2

What is the function of the right ventricle?

Answer 2

Pumps deoxygenated blood to the lungs where gas exchange takes place

Question 3

What is the function of the left ventricle?

Why does the left ventricle have a thicker muscular wall?

Answer 3

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

Question 4

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

Answer 4

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

Question 5

Describe the double circulatory system

Answer 5

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

Question 6

What are advantages of a double circulatory system?

Answer 6

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

Question 7

Describe the pattern of blood-flow through the heart

Answer 7

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

Question 8

What is natural resting heart rate controlled by?

Answer 8

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

Question 9

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

Answer 9

May use an artificial pacemaker as they correct irregularities

Question 10

What is an artificial pacemaker?

Answer 10

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

Question 11

What is the function of the coronary arteries?

Answer 11

Provide oxygen to the muscle cells of the heart

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

Question 12

What is the function of the heart valves?

Answer 12

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

Question 13

What is the function of the vena cava?

Answer 13

Brings in oxygenated blood from the body

Question 14

Suggest the effects of leaky / faulty valves on an athlete

Answer 14

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

Question 15

The body contains three different types of blood vessel.

What are they?

Answer 15

Arteries

Veins

Capillaries

Question 16

What is the function of the three blood vessels?

Answer 16

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

Question 17

How are arteries adapted to their function?

Answer 17

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

Question 18

How are veins adapted to their function?

Answer 18

Large lumen

Thin muscular wall as it transports low-pressure blood

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

Question 19

How are capillaries adapted to their function?

Answer 19

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

Question 20

Compare the structure of arteries, capillaries and veins

Answer 20

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

Question 21

What is blood?

Answer 21

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

Question 22

What is the function of blood plasma?

Answer 22

A liquid substance that transports dissolved substances around the body

Examples:

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

Question 23

What is the function of platelets?

Answer 23

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

Question 24

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

Answer 24

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

Question 25

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

Answer 25

Transport oxygen around the body to respiring cells

Question 26

What are the different blood components?

Answer 26

Plasma
Platelets
WBCs
RBCs

Question 27

How are red blood cells adapted to their function?

Answer 27

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

Question 28

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

Answer 28

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

Question 29

How are white blood cells adapted to their function?

Answer 29

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

Question 30

Give three uses of donated blood in medicine

Answer 30

• 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

Question 31

What are the risks of using blood products?

Answer 31

• 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)

Question 32

What is coronary heart disease?

What is its long-term effect if not treated?

Answer 32

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

Question 33

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

Answer 33

Statins (Drug)

Stents (Mechanical device)

Artificial hearts (Transplant)

Question 34

What is a statin, stent and artificial heart?

Answer 34

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

Question 35

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

Answer 35

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

Question 36

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

Answer 36

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

Question 37

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

What are the advantages of using stents?

Answer 37

Effective for many years

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

Surgery is quick

Question 38

What are the disadvantages of using stents to treat CHD?

Answer 38

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

Question 39

What is heart failure?

Answer 39

When the heart cannot pump sufficient blood around the body

Question 40

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

Answer 40

Keeps the patient alive whilst waiting for a donated heart transplant

Allows the heart to rest as an aid to recovery

Question 41

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

Answer 41

Risk of blood clotting

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

Surgery can lead to bleeding or infection

Question 42

What are the disadvantages of donated hearts?

Answer 42

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

Question 43

What is health?

Answer 43

Health is the state of physical and mental well-being

Question 44

What factors affect health?

Answer 44

Diet

Stress

Life situations

Diseases - both communicable and non-communicable

Question 45

Describe how different types of diseases may interact

Answer 45

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

Question 46

What is epidemiology?

Answer 46

Studying the patterns of disease to determine risk factors

Question 47

What are risk factors?

Answer 47

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

Question 48

Risk factors can be…

Answer 48

Aspects of a person’s lifestyle (sedentary)

Substances in the person’s body or environment

Question 49

What is a causal mechanism?

Answer 49

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

Question 50

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

What are some of these?

Answer 50

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

Question 51

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

Answer 51

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

Question 52

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

Answer 52

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

Question 53

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

Answer 53

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

Question 54

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

Answer 54

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

Question 55

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

Answer 55

• 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

Question 56

Why do the ventricles contract only after the atria contract?

Answer 56

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

Question 57

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

Answer 57

More oxygen
More glucose
More amino acids

Less carbon dioxide
Less lactic acid

Question 58

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

Question 59

Suggest why men and women commonly have different types of cancers

Question 60

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

Question 61

[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

Answer 61

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

Question 62

Cirrhosis of the liver leads to liver failure

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

Answer 62

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