B2 - Keeping Healthy

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  • Created by: StudentAM
  • Created on: 28-04-17 23:49
How are symptoms of infections caused?
by damage done to cells by microorganisms or the poisons (toxins) they produce
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Why do microorganisms (e.g. bacteria and viruses) reproduce rapidly?
The human body has ideal conditions (warmth, moisture, nutrients) which causes bacteria to reproduce large numbers.
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How long does it take for bacteria to reproduce?
every 20 minutes (eg. 2, 4, 16, 32)
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What are white blood cells?
are part of the body’s immune system and can destroy microorganisms by engulfing and digesting them or by producing antibodies
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What is the function of antibodies?
recognise microorganisms by the antigens that they carry on their surface, that different microorganisms have different antigens, and that a different antibody is therefore needed to recognise each different type of microorganism
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What happens once the body has made the antibody to recognise a particular microorganism?
memory cells can make that antibody again very quickly, therefore protecting against that particular microorganism in the future (immunity).
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What are vaccinations?
provide protection from microorganisms by establishing memory cells that produce antibodies quickly on reinfection
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What does a vaccine contain?
a safe form of a disease-causing microorganism
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How do you prevent epidemics of diseases?
vaccinate a high % of population, so the higher %, the unvaccinated will be protected too because the risk of coming in contact with an infected person will be very small.
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Why are vaccines and drugs (medicines) never completely risk-free?
individuals have varying degrees of side effects to them, due to genetic differences, people react differently to drugs and vaccines
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What chemical is used to kill, inhibit bacteria, fungi and viruses?
antimicrobials
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What are antibiotics?
type of antimicrobial that are effective against bacteria but not viruses
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What happens over a period of time to bacteria and fungi?
bacteria and fungi may become resistant to antimicrobials
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What change can happen to the microorganisms?
random mutations leads to different microbes which will be less affected by antimicrobials
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How do you avoid antibiotic resistance?
only use antibiotics when necessary and always complete the course
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Where are new drugs and vaccines first tested on?
for safety and effectiveness, by using animals and human cells grown in the laboratory
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Human trials can then be carried out by...
healthy volunteers to test for safety, on people with the illness to test for safety and effectiveness
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How long do human trials last?
some may last for a long time due to some drugs take a while to have an effect and show any side effects.
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Describe the 3 trials.
'open-label': BOTH patient and doctor know as treatment cannot be masked. 'Double-blind': NEITHER patient nor doctor know. 'Blind': patient doesn't know whether it's a drug or placebo - to test if patient gets better psychologically.
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What are ethical issues related to using placebos?
it's unethical to give fake treatment to somebody seriously ill.
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What is the role of the heart?
a double-pump muscular organ as the blood returns twice in the circulatory system, its
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Why do heart muscle cells need their own blood supply?
a constant supply of oxygen and nutrients, and for their waste products to be removed. so the heart requires its own blood supply in order to keep beating.
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What is the structure and function of arteries?
arteries carry blood AWAY from the heart TOWARDS the organs, It has a thick, elastic, muscular wall to cope with high pressures in the vessels.
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What is the structure and function of veins?
veins carry blood from organs INTO the heart. It has thinner walls than arteries with less elastic muscular fibre; lower pressure. valves to prevent back flow of blood
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What is the structure and function of capillaries?
capillaries allow FOOD and OXYGEN to diffuse to cells while waste is diffused from cells. It has narrow, thin-walled vessels which are only one cell thick - that allow them to perform effectively
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How can you measure heart rate?
by recording pulse rate
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How is blood pressure measured?
by recording the pressure of the blood on the walls of the artery
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What two values are given when blood pressure is measured?
SYSTOLIC: pressure from the heart as it contracts (HIGHER VALUE). DIASTOLIC: pressure from the force of the arteries as heart relaxes (LOWER VALUE)
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How are the 'normal' measurements for factors such as heart rate given?
within a range because individuals vary
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How do fatty deposits cause a heart attack?
fatty deposits build up in the vessel and form blood clots which lead to a heart attack
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How are heart attacks usually caused by?
lifestyle factors: smoking, poor diet, misuse of drugs, stress and/or genetic factors
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How can you reduce the risk of heart disease?
exercise, stop smoking, reduce salt intake in diet, maintain a healthy weight
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Where is heart disease more common in?
industrialised countries (UK, USA), as the rich can afford lots of high-fat food and often dont need to be physically fit
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how are factors that increase the risk of heart disease identified?
via epidemiological and large scale genetics studies
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What is homeostasis?
the maintenance of a constant internal environment
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How is this achieved?
by balancing bodily inputs and outputs using the nervous system and hormones to control the process.
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Why do automatic control systems throughout the body need to maintain a range of factors at steady levels?
this is required for cells to function properly
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What do these control systems have?
receptors - to detect changes in the environment. processing centres - to receive information and coordinate responses automatically. effectors - to produce the response
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What is negative feedback?
ensures that, in any control system, changes are reversed and returned back to the set level
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Describe the cycle.
SEE PAPER
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Why is a balanced water level important?
for maintaining the concentration of cell contents at the correct level for cell activity
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How are water levels controlled?
by balancing gains from drinks, food and respiration and losses through sweating, breathing, faeces and the excretion of urine
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Why are the kidneys a vital role?
by balancing levels of water, waste and other chemicals in the blood
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How do kidneys adjust the concentration and volume of urine produced?
when the water level of our BLOOD PLASMA is LOW, more water is reabsorbed back into the blood and the urine becomes more CONCENTRATED. When the water level of our BLOOD PLASMA is HIGH, less water is reabsorbed back into the blood and the urine b
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What does the water reabsorbed depend on?
External temperature - High → Concentrated urine, Low → Dilute urine . Level of exercise - High → Concentrated urine, Low → Dilute urine. Fluid intake - High → Dilute urine, Low → Concentrated urine. Salt intake - High → Dilute urine, Low → Conc. uri
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What hormone controls concentration of urine?
ADH
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Where is ADH released from?
released into the bloodstream by the pituitary gland
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How is ADH controlled by negative feedback?
When the level of water in the blood LOW > ADH is released > concentrated urine to be produced. When the level of water in the blood is HIGH > ADH is NOT released > DILUTE urine.
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What are the effects of Alcohol on water balance?
ALCOHOL > causes kidneys to produce GREATER VOLUME of MORE DILUTE urine, leading to DEHYDRATION. Alcohol SUPPRESSES (restrains) ADH production
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What are the effects of Ecstasy on water balance?
ECSTASY > kidneys produce a SMALL VOLUME of LESS DILUTE urine. Results to TOO MUCH water in body. Ecstasy INCREASES ADH production - kidneys reabsorb water.
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Other cards in this set

Card 2

Front

Why do microorganisms (e.g. bacteria and viruses) reproduce rapidly?

Back

The human body has ideal conditions (warmth, moisture, nutrients) which causes bacteria to reproduce large numbers.

Card 3

Front

How long does it take for bacteria to reproduce?

Back

Preview of the front of card 3

Card 4

Front

What are white blood cells?

Back

Preview of the front of card 4

Card 5

Front

What is the function of antibodies?

Back

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