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73 Cards in this Set
- Front
- Back
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Name three types of microorganism that can cause disease. |
viruses, bacteria, fungi |
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Describe two ways that microorganisms can cause the symptoms of an infectious disease. |
cell damage or toxins |
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List two different diseases caused by each type of organism. |
viruses: flu, polio, common cold, AIDS, measles bacteria: tonsillitis, tuberculosis, plague, cystisis fungi: athlete's foot, thrush, ringworm |
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Explain why bacteria can reproduce rapidly inside the body. |
they need a source of nutrients for energy, and they need warm, moist conditions so the chemical reactions inside them can take place the human body has lots of places where these conditions exist |
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What do viruses need to reproduce? |
other cells - they use parts of the other cells to make copies of themselves |
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How often do baceria reproduce? |
20 minutes in the right condition |
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What do you need to know to work out the size of a microorganism population after a certain amount of time? |
the number of microorganisms before reproduction starts how long it takes for one microorganism to reproduce how long the microorganisms are left to reproduce for |
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If you start with one bacterium that reproduces every 40 minutes, how many bacteria will you have after 6 hours? |
512 |
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What is the role of the immune system? |
fights of invading microbes always involves white blood cells |
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Describe the 6 steps white blood cells take to destroy incading microbes? |
microbes get into the body through a cut in the skin phagocytes (white blood cells) move from the blood vessels into the tissues phagocytes recognise the invading microbes microbes are engulfed by the phagocytes the phagocyte produces enzymes to destroy the microbes inside the cell some phagocytes release a chemical message to activate lymphocytes |
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What type of white blood cell makes antibodies? |
lymphocytes |
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What are antibodies? |
proteins that are specific to a particular antigen |
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What are antigens? |
substances that trigger immune responses, usually protein molecules on the surface of a microorganism cell |
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Give three different ways that antibodies help to get rid of infection. |
they mark the microorganisms so phagocytes can engulf and digest them they bind to and neutralise viruses or toxins some can attach to bacteria and kill them directly |
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What are memory cells? |
white blood cells that stay around in the blood which can reproduce very quickly if the same antigen enters the blood |
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What is immunity? |
when memory cells produce loads of antibodies and kill off the microorganisms before you become ill |
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Why must new antibodies be made for each different microorganism? |
the antigens on every microorganism are different |
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What is injected in a vaccination? |
dead or inactive microorganisms |
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Why do vaccinations work? |
the dead/inactive microorganisms still carry the same antigens |
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What are the benefits of vaccinations? |
you do not have to suffer the illness to be immune it prevents epidemics |
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What are the drawbacks of vaccinations? |
they are not completely safe for everyone people can suffer side effects |
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What are antimicrobials? |
chemicals that inhibit the growth of microorganisms or kill them without seriously damaging your own body cells |
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What are antibiotics? |
a type of antimicrobial that can kill bacteria
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Do antibiotics kill viruses? |
no, they do not work on the flu or colds |
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How do microorganisms become resistant to antibiotics? |
random genetic mutations may cause an organism to be less affected by a particular antimicrobial antibiotics kill the weaker bacteria, and if the course is not continued, the more resistant bacteria survive, created a resistant microorganism |
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Why are resistant bacteria a problem? |
they can't be treated with the same antimicrobials, so new ones must be created once bacteria become resistant |
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What increases the risk of antibiotic resistant bacteria emerging? |
not taking all the antibiotics a doctor prescribes for you |
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What are new drugs often developed using? |
human cells |
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After testing on human cells, what are new drugs tested on? |
at least 2 different species of live mammal |
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If the drugs are okay, what happens next? |
clinical trials |
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What is a placebo and why is it used? |
a fake drug, so there is no subconcious influence on the results based on their knowledge |
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What are the three types of trials? |
blind trials: doctor knows double-blind trials: no one knows open-label trials: everyone knows |
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What is transported in the blood? |
nutrients, oxygen, waste substances such as carbon dioxide |
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Which sides of the heart pump oxygenated or deoxygenated blood? |
right side - deoxygenated blood left side - oxygenated blood |
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What supplies blood to the heart? |
two coronary arteries which branch from the base of the aorta |
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What are the three types of blood vessels? |
arteries, veins, capillaries |
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Describe arteries. |
carry blood from the heart to the body cells comes out of the heart at high pressure strong and elastic artery walls |
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Describe veins. |
carry blood back to the heart lower pressure vein walls less thick than arteries have valves to help keep the blood flowing in the right direction have a bigger lumen |
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Describe capillaries. |
branches of arteries that are really tiny carry blood really close to every cell in the body to exchange substances permeable walls, so substances can diffuse in and out supply nutrients and oxygen, take away waste carbon dioxide walls are one cell thick - increases diffusion |
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What is the difference between your heart rate and your pulse rate? |
heart rate - the number of times your heart beats in one minute (BPM) pulse rate - number of times an artery pulsates in one minute |
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How is blood pressure measured? |
by taking a reading of the pressure of blood against the walls of an artery higher value is the pressure of the blood when the heart contracts lower value is the pressure of the blood when the heart relaxes |
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What is the inner lining of an artery like? |
smooth and unbroken |
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How can the inner lining of an artery wall be damaged? |
fatty deposits build up in damaged areas of arteries which restrict blood flow, causing high blood pressure |
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How does a blood clot form? |
a fatty deposit breaks through the inner lining of the artery |
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Why are blood clots dangerous? |
they could block the artery completely, or break away and block a different artery |
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How does a heart attack occur? |
coronary atery gets blocked, cutting off the blood supply to an area of the heart muscle |
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What lifestyle factors can increase the risk of heart disease? |
poor diet smoking stress misuse of illegal drugs excessive alcohol drinking |
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How do these 5 factors increase the risk of heart disease? |
poor diet - causes fatty deposits, caused by eating foods high in saturated fat and in salt stress - causes high blood pressure smoking - carbon monoxide and nicotine in cigarette smoke, carbon monoxide reduces the amount of oxygen in blood, nicotine raises blood pressure misuse of illegal drugs - increase heart rate which increases blood pressure excessive alcohol drinking - increases blood pressure |
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Where is heart disease more common and why? |
industrialised countries people can afford a lot of high-fat food and often don't need to be very physically active |
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What prevents the risk of developing heart disease? |
regular moderate exercise burns fat, stops it building up in arteries strenghens heart muscle |
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What are epidemiological studies? |
study of patterns of diseases and the factors that affect them |
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What is homeostasis? |
maintaining a constant internal environment |
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Give three examples in the body involving homeostasis. |
core body temperature, blood glucose, water levels |
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Why is homeostasis important? |
conditions inside your body need to be kept steady, even when the external environment changes important because your cells need the right conditions in order to function properly |
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What are the two main automatic control systems in your body? |
nervous system and hormonal system |
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What is a stimulus? |
a change in the environment |
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What is a receptor? |
something which detects a stimulus |
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What is the processing centre? |
it receives information and coordinates responses |
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What is an effector? |
an organ or gland that carries out a response |
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What is the mechanism that keeps your internal environment stable called? |
negative feedback |
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What is the importance of balancing water levels in the body? |
your body needs to maintain the concentration of its cell contents at the correct level for cell activity |
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What are the inputs and outputs of water in the body? |
inputs - water can be gained from drinks, food and respiration outputs - water can be lost through sweating, breathing, in faeces and in urine |
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What three things to the kidneys do to balance levels of water, waste and other chemicals? |
they filter small molecules from the blood such as water, sugar, salt and waste they reabsorb sugar, salt and water form urine from whatever is not reabsorbed which is excreted by the kidneys and stored in the bladder |
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What does the concentration of the urine depend on? |
the concentration of blood plasma |
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What factors cause blood plasma to vary? |
external temperature exercise level intake of fluids and salt |
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How does salt and water effect urine concentration? |
more salt - more concentrated more water - less concentrated |
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How does external temperature and exercise effect urine concentration? |
they cause sweating, which causes water loss |
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What hormone controls the concentration of urine? |
anti-diuretic hormone (ADH) |
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What is ADH released by? |
the pituitary gland |
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How does the brain monitor the water content of the blood? |
osmoreceptors in the brain detect the water content, this information is then passed on to the hypothalamus (processing centre) |
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What is the connection between ADH and urine concentration? |
more ADH - less urine less ADH - more urine |
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What effect does alcohol have on ADH production and why is it dangerous? |
it supresses ADH production, this could cause dehydration |
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What effect does ecstasy have on ADH production and why is it dangerous? |
it increases ADH production, this means less water can pass out of the body as urine |
