B2- Keeping Healthy

Question 1

How does infectious microorganisms damage cells?

Answer 1

Microorganisms produce poisons (toxins) that damage cells:

• some bacteria produce proteins that damage the material holding cells together. This helps bacteria invade the body more deeply.
• other microorganisms produce toxins that poison cells causing fever or inflammation.

Question 2

How do bacteria reproduce?

Answer 2

Bacteria reproduce by making copies of themselves. To do this they need a source of nutrients for energy.

Question 3

What conditions do bacteria reproduce in?

Answer 3

Bacteria need warm,moist conditions so the chemical reactions inside them can take place.

There are lots of places inside the human body where you can find these conditions - so bacteria become a large colony inside the body.

Question 4

How do viruses reproduce?

Answer 4

Viruses need other cells to reproduce- they use parts of other cells to make copies of themselves.

They can reproduce in the human body as there are lots of cells they could use.

Question 5

What is the immune system?

Answer 5

It is the human body’s natural defence system against any infectious microorganisms.

Question 6

What do white blood cells do?

Answer 6

• They detect anything “ foreign” to the body. (e.g. microorganisms)
• they then engulf and digest the microbes.
• These white blood cells are non specific and will attack anything that’s not meant to be there.

Question 7

What do specific white blood cells do?

Answer 7

• they have receptors that recognise particular antigens. They then make specific antibodies for those antigens.
• when the white blood cell recognises the antigens on the microorganism- it divides to make more identical- which make more antibodies to fight the infection.

Question 8

What are antigens?

Answer 8

Antigens are substances that trigger immune responses - they are protein molecules on the surface of a microorganism cell.

Question 9

What are antibodies?

Answer 9

Antibodies are proteins that are specific to a particular antigen.

Question 10

What do antibodies do?

Answer 10

• they mark microorganism so other white blood cells can engulf and digest it.
• they bind to and neutralise viruses or toxins.
• they attach to bacteria and kill them directly.

Question 11

What are memory cells?

Answer 11

Some white blood cells stay around in the blood after the original infection has been fought off - these are called memory cells.

They can reproduce quickly if the same antigen enters a second time.

The memory cells then produce loads of antibodies to kill the microorganism before the symptoms appear. This is called immunity.

Question 12

What is immunisation?

Answer 12

• It involves injecting inactive microorganism which have the same antigens which means the body will produce antibodies to attack them.
• the body also produces memory cells that recognise the antigens of the microorganism and stay in the blood.
• if the live microorganism of the same type appear after that, the memory cells can rapidly mass produce antibodies and kill them off.
• this means you do not feel any symptoms and are immune.

Question 13

What are epidemics?

Answer 13

Epidemics is big outbreaks of disease. To prevent this a large percentage of the population need to be vaccinated.

If a significant number are not vaccinated disease can spread quickly. However, if most people are vaccinated there are fewer people to pass on disease.

Question 14

Why can’t drugs/vaccines never be completely safe?

Answer 14

People experience side effects when using them. Genetic differences means people react differently to drugs and vaccines.

Question 15

What are antimicrobials?

Answer 15

They are chemicals that inhibit the growth of microorganisms or kill them, without damaging our body cells. They help clear up infections.

They kill bacteria but DONT KILL VIRUSES.

Antibiotics are a type of antimicrobials.

Question 16

What happens when a microorganism becomes resistant?

Answer 16

Microorganisms develop mutations to their DNA. This changes their characteristics. This means they get less affected by a particular antimicrobial.

For the microorganism, this is a HUGE advantage as they can survive better, longer and can reproduce.

This leads the gene for resistance to be passed on to the offspring- a part of natural selection.

Question 17

What are “superbugs”?

Answer 17

“Superbugs” are resistant to most known antimicrobials. They are becoming more common and are hard to get rid of.

Question 18

Why is it important to finish your antibiotics?

Answer 18

People stop taking their antibiotics as soon as they start to feel better. This increases the chance of antibiotic resistant bacteria emerging.

Question 19

Why are drugs tested in a lab first?

Answer 19

The drugs are developed using human cells that are grown in the lab. This means that you can measure the effect the drug has on real human cells.

However, it doesn’t recreate the conditions of a whole system or organism. So you can’t be sure whether it is safe or actually works.

Question 20

Who are drugs tested on first?

Answer 20

All drugs are tested on at least two different species of live mammal (e.g. Rats and monkeys) before given to humans.

This is to discard any harmful substances before humans get tested. Also, mammals have similar systems to humans so it gives early indications of what the drug might do to humans.

Question 21

Who gets tested first at the clinical trials?

Answer 21

The drug is tested on healthy human volunteers. This is to check for any harmful side effects on a healthy body.

Sick people are more vulnerable so they aren’t tested first.

Question 22

After healthy volunteers,who’s tested next?

Answer 22

If the results from the healthy volunteers are good. People suffering from the illness are tested. This is to check safety and effectiveness.

Question 23

What are placebos?

Answer 23

They are “fake” treatments which involve not giving the drug to the patient.

This is so you can compare the people who were given the drug and people who were given the placebo.

Question 24

What are blind trails?

Answer 24

The patient doesn’t know if they were given the drug or the placebo. This is because if the patient knows they are being treated they feel better for psychological reasons- even if they didn’t really improve. Blind trails eliminate these effects.

Question 25

What are double blind trails?

Answer 25

This is when even the scientists carrying out the research don’t know until the end which patients were given the drug and which were given the placebo.

This is so the scientist monitoring patients and analysing data aren’t subconsciously influenced by their knowledge.

Question 26

What are open label trails?

Answer 26

This is when the patient and the scientists are aware of the treatments that have been used.

Open label trails are used when you can’t mask the treatments being used.

Question 27

Why do human trails take a long time?

Answer 27

Because the drug may have a side effect which takes affect after a long period of time.

Question 28

How is blood circulated around the body?

Answer 28

Blood is circulated around the body through blood vessels.

Question 29

What does blood carry?

Answer 29

Oxygen and nutrients are carried in the blood to the body cells. Waste and carbon dioxide are carried away from cells.

Question 30

Describe the heart?

Answer 30

The heart is a double pumping organ that keeps blood flowing through the vessels.

The right side pumps deoxygenated blood to the lungs to collect oxygen and remove CO2.

The left side pumps the oxygenated blood around the body.

Question 31

Why does the heart need its own blood supply?

Answer 31

The heart is made up of muscle cells that keep the heart beating continuously.

These cells need their own supply of blood to deliver nutrients and oxygen to keep the heart beating.

Question 32

What are arteries?

Answer 32

• They carry blood away from the heart to the body cells ( including heart muscle)
• Blood comes out of the heart at high pressure so the artery walls are strong and elastic.

Question 33

What are veins?

Answer 33

• They carry blood back to the heart.
• The blood is at a lower pressure- so the walls don’t need to be thick.
• They have a big lumen than arteries to help blood flow easily.
• They have valves to help blood flow in the right direction.

Question 34

What are capillaries?

Answer 34

• They are branches of tiny arteries.
• They carry the blood really close to every cell in the body to exchange substances with them.
• They have permeable walls so substances can diffuse in and out.
• They supply nutrients and oxygen and take way waste like CO2.
• Their walls are one cell thick. This increases the rate of diffusion by decreasing the distance over which it happens.

Question 35

What is heart rate?

Answer 35

The number of times your heart beats in one minute.

It’s measured in BPM (beats per minute)

Question 36

What is pulse rate?

Answer 36

The number of times an artery pulsates in one minute.

The pulsation of an artery is caused by blood being pumped through it by a heart beat.

Question 37

What is high and low blood pressure?

Answer 37

When your heart muscle contracts blood is forced out of the heart. This increases the blood pressure.

When the heart muscle relaxes the heart fills with blood and your blood pressure decreases.

Question 38

How do you measure blood pressure?

Answer 38

By taking a reading of the pressure of the blood against the walls of an artery.

Blood pressure measurements have two values. The higher value is the pressure of blood when the heart contracts.

The lower value is the pressure of blood when the heart relaxes.

Question 39

How does high blood pressure increase the risk of heart disease?

Answer 39

• The inner lining of an artery is usually smooth and unbroken. HBP damages this.
• Fatty deposits build up in damaged arteries - this restricts blood flow and cause HBP.
• If the fatty deposits breaks through the lining of an artery a blood clot forms.
• The blood clot blocks the artery. Or it could break it and block a different artery.
• If a coronary artery is blocked the heart muscle will be cut off from its blood supply - receiving no oxygen. This is a heart attack.
• A heart attack can cause serious damage and causes death of the heart muscle.

Question 40

How do lifestyle factors increase the risk of heart disease?

Answer 40

• Poor diet- cholesterol makes arty deposits- saturated fats in food- High salt diet- HBP.
• Smoking- nicotine increases heart rate- carbon monoxide reduces oxygen in the blood-increased risk of heart disease.
• Drugs- ecstasy- increase in heart rate- HBP.
• Alcohol- HBP (high blood pressure)
• Stress- increase HBP- increased risk.

Question 41

How to prevent heart disease?

Answer 41

• regular moderate exercise- burns fat- strengthens heart.

* heart disease common in industrialised countries (UK, USA) because people can afford high fat foods.

Question 42

What are epidemiological studies?

Answer 42

The study of patterns of disease and the factors that affect them.

The study helps identify the lifestyle risk factors. You look for similarities in the people who died from the same illness. (Poor diet, smoking etc.)

They have genetic studies to identify genetic risk factors. You look for genetic similarities between people.

Question 43

What are the effects of an infection called?

Answer 43

The effects that an infection has on the body ( e.g. Fever, rash) are called the symptoms.

The damage is done to the body’s cells.

Question 44

What is homeostasis?

Answer 44

• It is balancing the inputs with outputs to maintain a constant internal environment.
• The conditions in your body need to be steady even when the external environment changes. This is so cells have the right conditions to function.
• We have automatic control systems in our body that regulate our internal environment- these include both nervous and hormonal communication systems.

Question 45

What is negative feedback?

Answer 45

When something is too high or too low your body uses negative feedback to bring it all back to normal.

• Receptor detect a change in the environment (e.g. Level is too high)
• The processing centre receives the information and coordinates a response.
• Effectors produce a response which counteracts the change. (level decreases)

Question 46

What if the effectors make too much change?

Answer 46

The effectors will continue producing a response as long as it’s simulated by the processing centre.

If the level changes too much the receptors detect it and negative feedback starts again.

Question 47

Why is balancing water content important?

Answer 47

The body needs to maintain the concentration of its cell contents at the correct level for cell activity.

Question 48

What are inputs and outputs?

Answer 48

Inputs- water gained by food,drink and respiration.

Outputs- water lost by sweating, breathing, faeces and urine.

Question 49

What do the kidneys do?

Answer 49

• They filter small molecules from the blood, including water, sugar, salt and waste.
• They reabsorb all sugar, as much salt and water the body requires.
• Whatever isn’t reabsorbed forms urine which is excreted by the kidneys and stored in he bladder.

Question 50

What types of urine is there?

Answer 50

The kidneys makes dilute or concentrated urine.

The concentration of urine depends on the concentration of the blood plasma- which varies with external temperature, exercise and the intake of fluids and salt.

Question 51

Factors that affect urine?

Answer 51

Temperature-you sweat more-water loss-kidneys reabsorb more water into blood-produces a small amount of concentrated urine.

Exercise-you sweat more-produces a small amount of concentrated urine.

Intake of fluids and salts- not drinking enough water- eating too much salt- produces concentrated urine.

Drinking lots of water- produces lots of dilute urine.

Question 52

What is ADH?

Answer 52

• The concentration of urine is controlled by a hormone called anti-diuretic hormone (ADH).
• It is released into the bloodstream by the pituitary gland.
• The brain monitors the water content of the blood and instructs the pituitary gland to release ADH into the blood according to how much is needed.
• The process of water regulation is controlled by negative feedback. This means if the water content gets too high or too low the mechanism will be triggered and brings it back to normal.

Question 53

How does alcohol affect ADH?

Answer 53

• drinking results in larger amounts of more dilute urine (than normal) being produced.
• alcohol suppresses the production of ADH so kidneys will reabsorb less water.
• this means more water passes out the body as urine. Which causes dehydration.

Question 54

How does ecstasy affect ADH?

Answer 54

• Ecstasy results in smaller amounts of more concentrated urine (than normal) being produced.
• it causes the production of ADH to increase so the kidneys will reabsorb more water.
• this means less water can pass as urine from the body.