Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
166 Cards in this Set
- Front
- Back
|
Why do we eat? |
To get the nutrition our body needs from food |
|
|
What does good nutrition provide us with? |
Better health Ensure stronger immune system Learn more effectively Makes us stronger More productive |
|
|
What is a balanced diet? |
One that contains all nutrients required for health in appropriate portions |
|
|
What are the seven components of a balanced diet? |
Carbohydrates - main source of en Proteins - essential for growth + repair of tissue Fats - essential source of en + important in cell membranes, waterproofing, absorption of fat-soluble vitamins etc Vitamins - important role in chemical processes in cells -some water sol some fat sol Minerals - inorganic elements occurring in body that are essential to its normal function Water - transports substances + main component of body (60% water) Fibre or roughage - indigestible pt of good - essential for functioning of digestive system |
|
|
What are the general portions of energy intake from nutrients in diet? |
- 57% carbohydrates - 30% of fats - 13% proteins |
|
|
What causes malnutrition? |
An unbalanced diet |
|
|
What is obesity? |
When a person is 20% or more heavier than recommended weight for their height |
|
|
What BMI score qualifies as obese? |
30 or more |
|
|
How does the location where the fat is deposited affect health? |
People w/extra fat around middle known to be more @ risk than those w/ it around hips and thighs |
|
|
How do you work out BMI? |
Mass in kg/(height in m)^2 |
|
|
What are the health risks attached to obesity? |
Cancer Cardiovascular disease Type 2 diabetes Gallstones Osteoarthritis High blood pressure |
|
|
What causes coronary heart disease? |
Atherosclerosis - deposition of fatty substances in walls of coronary arteries causing a narrowed lumen and restricting blood flow to heart muscle |
|
|
How will salt increase the risk of developing CHD? |
Excess salt = descrease water potential of blood as result = more water held in blood + pressure increases Hypertension - condition which blood pressure (particularly diastolic press) is maintained @ level too high Hyper tensions can damage inner lining of arteries - one of early steps in atherosclerosis |
|
|
How does fat increase the risk of developing CHD? |
Animal fats - tend to be saturated which are more harmful than unsaturated fats (i.e. plant fats) Polyunsaturated + monounsaturated fats = particularly beneficial to health |
|
|
How does cholesterol increase risk of developing CHD? |
Too much cholesterol in blood = harmful - has been linked to 45-47% of deaths from CHD Conc of chol should be maintained below 5.2mmol dm^-3 |
|
|
Why is cholesterol found in the body? |
Its essential to normal functioning - found in membranes and skin - used to make steroid sex hormones + bile |
|
|
What is cholesterol converted to for transport? |
From insoluble cholesterol to the form of soluble lipoproteins |
|
|
What types of lipoproteins are there? |
High-density lipoproteins (HDL) Low-density lipoproteins (LDL) |
|
|
How are these lipoproteins transported? |
They're released into blood + can be taken up by cells that have correct receptor sites |
|
|
What are HDLs made up of? |
A combo of unsaturated fats, cholesterol and protein |
|
|
What do HDLs tend to carry? |
Cholesterol from the body tissues back to the liver |
|
|
Why are HDLs associated with reducing blood cholesterol levels? |
Bc liver cells have receptor sites that allow HDLs to bind to them - then can be broken down or used for metabolic processes like making bile |
|
|
Why else are HDLs beneficial? |
They reduce deposition in artery walls by atherosclerosis and may even remove the deposits And they're made of unsaturated fats which are known to be more beneficial to health |
|
|
What are LDLs made up of? |
Combo of saturated fats, cholesterol and protein |
|
|
What do LDLs tend to carry? |
Cholesterol from the liver to tissues - tissue cells have receptor sites which allow LDLs to bind to their plasma membranes |
|
|
What are the effects of too much saturated fat + cholesterol consumption? |
LDLs in blood will rise - which causes deposition in artery walls |
|
|
How do different fats affect the LDL receptors? |
1. Saturated fats thought to decrease activity of LDL receptors - therefore level of LDLs in blood rises 2. Polyunsaturated fats increase activity of LDL receptors -thus decrease concentration of LDLs in blood 3. Monounsaturated fats - seem to help remove LDLs from blood |
|
|
How are higher levels of HDLs and lower levels of LDLs maintained in the body? |
Eating a low fat diet will reduce overall concentration of lipoproteins Eating a high portion of unsaturated fats will increase proportion of HDLs in blood Eating polyunsaturated + monounsaturated fats help reduce levels of LDLs in blood |
|
|
What is a herbivore? |
An animal that makes use of biological molecules when eating and digesting plants |
|
|
What is an omnivore? |
Consuming both plants and animals - gaining nutrition both directly from plants and indirectly from animals (herbivorous animals) |
|
|
How can we make food production in plants more efficient? |
Improve growth rate of crops Increase size of yield from each plant Reduce losses of crops due to disease + pests Make harvesting easier by standardising plant size Improve plant responses to fertilisers |
|
|
How can we make food production more efficient in animals? |
Improve rate of growth Increase productivity Increase resistance to disease |
|
|
What is selective breeding? |
When humans select individual organisms that are allowed to breed according to chosen characteristics artificial selection as its intentional breeding of certain traits |
|
|
What are the three stages of selective breeding? |
Isolation Artificial selection In breeding or line breeding |
|
|
Describe the process of selective breeding |
Select pair of animals/plants displaying desirable characteristics Allow them to reproduce Offspring sorted carefully to select those w/best combo of characteristics -only these allowed to reproduce This continues for generations -till the characteristics become more exaggerated |
|
|
How does selective breeding come about? |
By applying selection pressure on the animal/plant |
|
|
What is marker-assisted selection? |
Section of DNA = used as marker to recognise desired characteristic Once offspring have been produced from selected parents - DNa is checked for marker at early stage |
|
|
Examples of selective breeding |
Farmers breed cattle for high milk yield or meat production Farmed salmon have been selected to grow more quickly so time-to-time market have been cut by 30% Chickens bred for egg or meat production -egg-layers can produce over 300 eggs p/y |
|
|
Examples of marker-assisted selection |
Tomatoes have been bred w/improved disease resistance -wild tomato variety w/good resistance to yellow leaf curl virus; allele was identified + bred in domestic variety |
|
|
What are fertilisers? |
Minerals needed for plant growth; contain chemicals like nitrate, potassium and phosphate Replacing minerals in soil Increase rate of growth + overall crop sizes |
|
|
What are pesticides? |
Chemical designed to kill organisms that cause disease in crops (pests) Eg: fungicides reduce effect of fungal growth in leaves or roots |
|
|
What is an antibiotic? |
Chemical that kills/prevents reproduction in bacteria
- infected animals treated w/antibiotics to reduce spread of disease among animals that are intensly farmed |
|
|
What is food spoilage? |
Microorganisms digesting and leaving behind waste products on food; making a noticeable effect |
|
|
What are the four main ways of food spoilage? |
1/ Visible growth of microorgs on food (e.g.moulds like Penicillum which goes green)
2/ External digestion - releasing enzymes in food + absorbing nutrients released (sweet smell) 3/ Bacterium Clostridium botulinium releases toxin botulin - causes botulism // 1ug can kill 4/Presence of microorgs can cause infection - eg salmonella in poultry attacks lining of stomach |
|
|
Name the 7 methods of preventing food spoilage |
1. Cooking 2. Pasteurising 3. Drying, salting and sugar coating 4. Smoking 5. Pickling 6. Irradiation 7. Cooling and freezing |
|
|
Outline how the 7 methods prevent food spoilage |
1/ heat denatures enzymes + proteins in it 2/ heating to 72 degrees for 15 secs then cooling rapidly to 4 - drop in temp kills microorg 3/ dehydrates any microorgs as lowers water potential outside it - water leaves by osmosis 4/ food develops hardened, dry outer surface - smoke contains antibacterial chems 5/ uses acid pH to kill microorgs by denaturing proteins + enzymes in it 6/ ionising rad kills microog by disrupting DNA structure 7/ these retard enzyme activity; slowing down metabolism, growth & reproduction |
|
|
What are further methods to prevent contamination? |
1. Canning - sealing food in airtight cans 2. Vacuum rapping - air is excluded so microbes can't respire aerobically 3. Any plastic or paper packaging |
|
|
How are microorganisms used to make food? |
Yoghurt is milk thats been affected by Lactobactillus-causes milk protein to coagulate Cheese- made from curdled milk - solid portion of milk is contaminated by Penicillum to make blue cheese Bread - made to rise by yeast Alcohol = produced by anaerobic resp of yeast - cereal grains containing maltose can be used to brew beer |
|
|
How has recent manufacturing or microorganisms been used to make food directly? |
Protein = single-cell protein(SCP) - used in quorn - a mycoprotein (protein made by fungus) |
|
|
Advantages of using microorganisms |
Production of protein = many times faster than animal/plant protein Production can be increased/decreased according to demand No animal welfare issues Provide good source of protein for vegetarians Protein contains no animal fat/cholesterol SCP prod could be combined w/removal of waste products |
|
|
Disadvantages of using microorganisms |
Many people wont want to eat fungal protein - or food grown from wate Isolation of protein - microbe needs to be isolated from material on which they growb bc they're grown in huge fermenters Protein has to be purified to ensure its not contaminated Conditions needed also ideal for pathogenic microbes Palatability - protein don't have taste/texture of traditional sources |
|
|
What is health? |
A state of mental, physical and social wellbeing and not just the absence of disease |
|
|
What are features of good health? |
Free from disease Able to carry out normal, physical and mental tasks expected in modern society Well fed, w/balanced diet Usually happy w/positive outlook Suitably housed w/proper sanitation Well integrated into society |
|
|
What is disease? |
A departure from good health caused by malfunction of the mind or body symptoms can be physical, mental or social |
|
|
What are infectious diseases? |
Diseases caused by living organisms Symptoms usually physical but can have an effect on mental and social health |
|
|
What are parasites? |
Organisms that live in or on another living thing (host) Cause harm to the host by taking nutrition from them |
|
|
What is an external parasite? |
A parasite that lives on its host eg head louse |
|
|
What is an internal parasite? |
A parasite that lives inside their host eg tapeworm |
|
|
What can occur if parasites become too numerous? |
They may become a huge burden to host - causing damage that allows other organisms to invade host and cause secondary infection |
|
|
How do bacteria cause infectious diseases? |
Bacteria reproduce rapidly (every 20 mins) - once in human body they continue to reproduce Presence can cause disease by damaging cells or releasing waste products that are toxic Examples; cholera caused by Vibrio cholerae, Tuberculosis caused by Myobacterium tuberculosis and Myobacterium bovis |
|
|
How does fungi cause infectious diseases? |
Athletes foot + ringworm caused by fungus Tinea - more examples; Microsporum, trichophyton and epidermophyton Fungus lives on skin + sends out reproductive hyphae that grows on skin to release spores -- causing redness and severe irritation |
|
|
How do viruses cause infectious diseases? |
They invade cells + take over their genetic machinery; causes cell to manufacture more copies of virus to reproduce - eventually cell bursts releasing these Eg; HIV/AIDS, influenza, common cold |
|
|
How do protoctista cause infectious diseases? |
Enter host cells and feed on contents as they grow; eg Amoeboid dysentery and malaria disease = Plasmodium has immature forms that feed on contents of RBCs (malarial parasite) |
|
|
What must a pathogen be able to do in order to cause disease? |
Travel from one host to another Get into host's tissues Reproduce Cause damage to host's tissues |
|
|
What are the most common forms of transmission? |
Vector Physical contact Droplet infection |
|
|
What causes malaria? |
Caused by eukaryotic organism from genus Plasmodium - Plasmodium falciparium - Plasmodium vivax - Plasmodium malariae spread by vector - female Anopheles mosquitoes carry plasmodium in their proboscis can also be spread by unhygenic medical practises like unscreened blood transfusions - or use of unsterilised needles Also can be passed across placenta to unborn child |
|
|
Describe the cycle as to which malaria is transmitted in |
Host w/malaria - mosquito will suck parasite gametes into its stomach Gametes fuse + form zygotes in its stomach Infective stages formed + move to it's salivary glands When it bites another - injects little saliva as anticoagulant Saliva contains infective stage of parasite In human - infective stage enters liver where they multiply b4 passing into blood again; In blood they enter RBCs where gametes produced |
|
|
What causes HIV/AIDS? |
Caused by human immunodeficiency virus Virus enters body + remains inactive (HIV +ve) Once active - it attacks + destroys Th cells - thus ability to resist infection is reduced May contract range of opportunistic infections - effect of these disease that eventually kill AIDS = acquired immune deficiency syndrome |
|
|
How is HIV transmitted? |
Exchange of bodily fluids (eg blood to blood) Unprotected sex Unscreened blood transfusions Use of unsterilised surgical equipment Sharing hypodermic needles Accidents such as 'needle-stick' Across placenta or during child birth Breast feeding |
|
|
What causes tuberculosis? |
Bacterium - mycobacterium tuberculosis or m. bovis TB usuallly found in lungs Transmittedby droplet infection Thought that 30% of world population infected in many its inactive/controlled by immune system Bacteria contained in tiny droplets of liquid = released when an infected person sneezes, talks or coughs inhalation of droplets infects |
|
|
How is TB transmitted?
|
Overcrowding - many people living/sleeping in one house Poor ventilation Poor health - esp if person has HIV/AIDS Homelessness Living/working w/people who've migrated from areas where TB is common From milk/meat of cattle |
|
|
Why are diseases important? |
Bc WHO maintains that good health is a human right Poor health causes a lot of suffering Economic cost as result of need for med services People who are ill can't work Some don't have access to basic requirements 4 good health |
|
|
What aspects of developing countries contribute to poor health? |
Poverty Lack of proper shelter Lack of purified water Poor nutrition Poor hygiene Lack of investment by gov Inadequate health services Inadequate education about cause of diseases Civil unrest/warfare Inadequate transport facilities preventing someone from reaching medical assistance |
|
|
How has malaria impacted the world? |
It kills about 3 million per yr 300 million are affected by it worldwide Limited to areas where Anopheles can survive - currently tropical regions 90% of infected people live in sub-saharan africa |
|
|
How has HIV/AIDS impacted the world? |
Still spreading in pandemic proportions Approx 45 mill living w/ them at end of 2005 More than 1/2 in sub-Saharan africa Nearly 30 million have died from HIV/AIDS related disease Aids spreading rapidly, in China, russia and other Eastern EU countries |
|
|
How has TB impacted the world? |
TB declared a public health emergency in 1993 - since then no of cases rose steadily each yr Approx 1% of world's population is newly infected each yr 10-15% of those go on to develop the disease Percentage of world pop struck by TB peaked in 2004; 2005 - 8.8mill new cases of TB recorded + 1.6mill died Suggested that 30% of world pop = infected atm Particularly common in SE Asia + sub-sah africa |
|
|
How do health organisations use epidemiology to study the spread disease? |
Identify causes of disease Identify risk factors Determine incidence of diease Determine prevalence of diseas Determine mortality Determine morbidity Study how quickly it spreads Identify disease as endemic, epidemic or pandemic Identify countries at risk Identify pts of population at risk Check how well control programmes are working |
|
|
How can health organisations use their resources to help reduce the effects of disease? |
Targeting education programmes at those most at risk - to inform them of risks and how to avoid them Targeting adverts to raise awareness Targeting screening programmes to identify individuals at risk Providing specialised healthcare in certain areas Providing vaccination programmes for major diseases Targeting research to find cures for major diseases |
|
|
What are the primary defences? |
The mechanisms that have evolved to prevent pathogens from entering the body |
|
|
State a few primary defence mechanisms in the body? |
Skin Mucous membranes Tear fluid Ear wax Acidic conditions in vagina |
|
|
How is the skin a primary defence mechanism? |
Epidermis consists of layer of cells called keratinocytes - these produced by mitosis at base of epider As these cells migrate out to surf of skin -they dry out + cytoplasm = replaced by keratin --* keratinisation By the time the cells reach surface- theyre dead - and these slough off Keratinised layer acts as effective barrier to pathogens |
|
|
How are mucous membranes a primary defence mechanism? |
Certain substances must enter our blood - leaving body exposed to infection as barrier btwn blood + environment reduced Areas like airways + lungs and digestive system - great potential for infection Air + food could be harbouring many microbes These areas = protected by mucous membranes; goblet cells in epithelial layer secrete this This layer lines + traps invading pathogens Epithelium also contains ciliated cells - these waft mucus along and out of throught Most pathogens = killed in digestive system bc of acidity of stomach (pH1 or 2) - denaturing enzymes These membranes also found in gut, genital areas, anus, ears and nose |
|
|
What are the features of neutrophils as phagocytes? |
Neutrophils - most common - have a multilobed nucleus - manufactured in bone marrow - travel in blood + often squeeze out into tissue fluid - may be found on epithelial surfaces like lungs -short-lived but will be released in large numbers as result of infection |
|
|
What are the features of macrophages as phagocytes? |
- larger cells - manufactured in bone marrow - travel in blood as monocytes - tend to settle in body organs (usually lymph nodes) -they develop into macrophages in lymph nodes - play important role in specific responses to invading pathogens |
|
|
How do phagocytes fight against invading pathogens? |
They engulf and ingest them to destroy the pathogen |
|
|
How do phagocytes work? |
1/ pathogen is identified by the antigen (chemical marker) in its outer membrane 2/ proteins in blood (antibodies) attach to foreign antigens 3/ receptor sites on phagocytes bind to antibodies on pathogen 4/ once phagocyte binds -it will envelop pathogen by folding its membrane inwards 5/ pathogen now trapped in vacuole called a phagosome 6/ lysosomes then fuse w/phagolysosome and release enzymes into it (lysins) 7/ lysins digest bacterium + produce harmless nutrients that can be absorbed into cytoplasm 8/ neutrophils short-lived + will die soon after digesting few pathogens - may collect in infected area to form pus |
|
|
What are the roles of macrophages? |
They initiate specific response to a disease; immune response |
|
|
What is the immune response? |
The activation of lymphocytes in the blood and production of antibodies in order to respond to a pathogen |
|
|
How do infected cells activate the immune response? |
1/ release chemicals such as histamine which attracts neutrophils to infected area 2/ histamine also causes capillaries to become more leaky 3/ more fluid leaves capillaries in area of infection 4/ causes swelling and redness = and more tissue fluid passes into lymphatic system 5/ leads pathogens towards macrophages waiting in lymph node |
|
|
What are antigens? |
Molecules that stimulate an immune response |
|
|
What are features of antigens and how do they stimulate the immune response? |
Usually large molecules have a specific shape foreign antigen will be detected by the immune system + stimulates production of antibodies - antibodies specific to antigen Antibodies are specific to the organism - usually protein or glycoprotein in or on plasma membrane Antibodies bind to antigens |
|
|
Why don't our own antigens stimulate the immune response? |
Because our immune system recognises our own antigens |
|
|
What produces antibodies? |
Lymphocytes in the immune systen |
|
|
What are antibodies and their features? |
Large proteins and also known as immunoglobulins Specific shape complementary to that of a specific antigen Antibody must be manufactured for every antigen that is detected Antibodies attach to antigens and render them harmless |
|
|
Describe the structure of an antibody |
*Y shape w/ two distinct regions *4 polypeptide chains held by disulfide bridges *Constant region (same for all antibodies) - enables antibody to attach to phagocytic cells *Variable region - specific shape and differs from one antibody to another (result of AA sequence) - ensures it binds to correct antigen *Hinge regions allow certain degree of flexibility; allow y brances to move to attach to an antigen |
|
|
How do antibodies work? |
NEUTRALISATION Attach to antigens on a pathogen which blocks its ability to bind to host cell receptor site AGGLUTINATION antibodies can resemble several y shaped molecules attatched to eachother - thry act as binding site to antigen on pathogen and cause many to attach at once - sticking together |
|
|
What is the primary immune response? |
Initial stimulation of the production of antibodies after an infecting agent is first detected - usually after a few days |
|
|
What is the secondary immune response? |
Production of antibodies if the body is infected a second time by the same pathogen - this time production starts much sooner +more rapid - it also reaches a much much higher conc |
|
|
What is cell signalling? |
The communication between cells that allows effective coordination of a response |
|
|
How is cell communication achieved? |
Through cell surface molecules and through the release of hormone-like chemicals; CYTOKINES Target cell has receptor site complementary to the shape of a foreign antigen Once antigen is detected - lymphocyte is activated/stimulated |
|
|
How is identification communicated? |
Pathogens carry antigens on cell surf - these act as flags saying 'i am foreign' - these = detected by body cells |
|
|
How are sending distress signals communicated? |
After pathogens are damaged by body cell - pts of it will often end up attached to host's plasma membrane - two effects; 1/ can act as distress signal + can be detected by cells from immune system 2/ act a markers to indicate host is infected - T killer cells can recognise its infected + it must be destroyed |
|
|
How is antigen presentation communicated? |
Macrophages in lymph nodes act like phagocytes - to engulf + digest pathogen -- don't fully digest it; they separate out antigens + incorporate them into cell surf mol this is exposed on surface of macrophage * becomes known as antigen-presenting cell its function = find lymphocytes that can neutralise that particular antigen |
|
|
How are instructions communicated? |
Cytokines are released by cells these act as instructions to their target cells they act over short distances @ low conc act by binding 2 specific membr-bound receptor - on target cell causes release of second messengers inside cell - alters its behav through gene expression |
|
|
What does communication using cytokines include? |
1. Macrophages release monokines - attracting neutrophils by chemtaxis 2. Macrophages release monokines that stimulate B cells - to diff + release antibodies 3. T cells, B cells + macrophages release interleukins - stimulating prolif + diff of B and T cells 4. Many cells release interferon - inhibit virus replication + stimulate activity of T killer cells |
|
|
What is the immune response? |
A specific response to the detection of pathogens in the body |
|
|
What does the immune response involve? |
B lymphocytes, T lymphocytes w/ large nucleus and specialised receptors - on plasma membranes Produces antibodies+ provides long term protection from disease |
|
|
What is immunological memory? |
Long-term protection from a disease through the release of memory cells which circulate in body for no of yrs |
|
|
What stimulates the specific immune response? |
Once correct T or B lymphocyte detects the foreign antigens - it engulfs and digests the pathogen + becomes an antigen presenting cell Commonly macrophages This acts as flag to locate correct lymphocytes and bring them to the infected area (T helper and T killer cells) - known as clonal selection Many copies of the pathogen's antigens are displayed on various cells -- known as clonal expansion |
|
|
Describe the humoral response |
T helper cells reproduce (clonal expansion) Release interleukins These activate B cell development + reproduction (proliferation) - these also stimulate phagocytosis They will differentiate into two types of B cells; plasma cells - flow around blood manufacturing + releasing antibodies b memory cells - acting as immunological memo |
|
|
Describe the cell-mediated response |
After clonal selection of T killer cells; T killer cells reproduce (clonal expansion) - proliferation T killer cells search for infected cells They attach to these cells + secrete hydrogen peroxide into them - killing the cell and pathogens it contains |
|
|
What is a vaccination? |
A deliberate exposure to antigenic material which activates the immune system to make an immune response + provide immunity |
|
|
What is artificial immunity? |
A person being injected w/ either the antibodies made by another individ * OR injecting them w/weakened or dead pathogen to stimulate their own immune response |
|
|
What forms can antigenic material used in vaccines take? |
1/ Whole, live microbes - usually ones not as harmful as those causing real disease - must have similar antigens so antibodies produced will be effective 2/ Harmless/attenuated version of pathogenic organism 3/A dead pathogen 4/ Preparation of antigens from a pathogen 5/ Some harmless toxin |
|
|
How can vaccines be taken? |
By injection or orally |
|
|
What is herd vaccination? |
Using a vaccine to provide immunity - to all or almost all population @ risk - once enough people are immune = no longer can spread - to eradicate smallpox - 80-85% were vaccinated - in UK = vaccination programmes to immunise young children against; TB, diphtheria, tetanus, whooping cough, polio, meningitis, measles, mumps and rubella |
|
|
What is ring vaccination? |
Used when a new case of disease is reported Involves vaccinating all people in immediate vicinity of new case - may mean vaccinating those in surrounding houses Used in many pts of world to control spread of livestock disease |
|
|
What is influenza? |
A killer disease caused by a virus
Affects the respiratory system |
|
|
Who are the people most vulnerable to contracting influenza? |
People aged over 65 years and those with other respiratory tract conditions |
|
|
Example of an influenza epidemic? |
1918 - flu epidemic killed at least 40 million people worldwide 1968/69 - flu pandemic - one million killed by Hong Kong flu |
|
|
What has been done to avoid another pandemic or epidemic? |
People at risk may be immunised - eg in UK there is a vaccination programme to immunise all those aged over 65 -- and those at risk for any other reason EG; 2006/7 74% of those over 65 were vaccinated Research is undertaken to determine which strains of flu are most likely to spread that yr |
|
|
What is active immunity? |
Achieved by the activation of the immune system - eg lymphocytes in body manufacturing antibodies and releasing them into blood -- and providing immunity |
|
|
What is passive immunity? |
Provided by antibodies that haven't been manufactured by the stimulation of the recipient's immune system - may be provided across the placenta to a baby - of via breast milk Also can be done by intravenous injections - usually short-lived |
|
|
What is natural immunity? |
Gained in the normal course of living processes - gained as a result of infection that stimulates the immune response *eg; antibodies via breast milk or immunity after an injection |
|
|
Why is there a need for new medicines and drugs? |
New diseases are emerging Still many diseases w/no effective treatments Some antibiotics becoming less effective - selection pressure + evol has led to resistance |
|
|
How are new drugs discovered (list)? |
By accident Traditional medecine Anaesthetics Observation of wildlive Modern research |
|
|
How are new drugs discovered by accident? |
Greatest example - Fleming's discovery of Penicillin - most antibiotics used today = made by Streptomyces bacterium Antibiotics like neomycin chloramphenicol and streptomycin use this Streptomycin now rarely used bc of resistance |
|
|
How are new drugs discovered from traditional medicine? |
Many drugs have been used for centuries WHO calculates 80% of population relies on traditional medicine in india; 7000 diff plants = used for their medicinal properties |
|
|
How are new drugs discovered from anaesthetics? |
Sap of unripe poppies = used in Neolithic times - in pts of southern Europe + egypt in 12th cent; opium from poppies = used as anaesthetic by 19th cent; morphine + opium were being used These reduce nervous action in CNS - so no pain is felt |
|
|
How are new drugs discovered by observing wildlife? |
Animals can be self-medicating eg; monkeys, bears + others rub citrus oils on their coat as insecticides - + antiseptics prevent insect bites + infection Chimpanzees swallow leaves folded in certain way - to remove parasites from digestive tract Elephants roam miles to find clay to counteract dietary toxins |
|
|
How are new drugs discovered through modern research? |
Use of traditional plant medicines + animal behav - starting point in their search 4 new drugs Research into plants allows them to isolate the active ingredient |
|
|
How is aspirin an example of the discovery of a new drug? |
Hippocrates used extract from willow park to relieve pain + fever Not till 1928 - Johann Buchner extracted the active ingredient; salicin This could be used to relieve pain but caused stomach bleeding (side effect) - 1897 - found to reduce this by adding acetyl group to salicin *by 1971 - further research found that salicin worked by inhibiting enzymes - enzymes involved in synthsis prostaglandins |
|
|
How have we been searching for new natural medicines? |
Concentration placed on tropical plants - there are hopes there may be new medicinal drugs to discover May be potential uses of wild and cultivated plants in UK New chem fingerprinting tech enables scientists to screen natural chems more effectively - for their activity as potential medicines |
|
|
How has further research been used on the hunt for new drugs? |
biologists hope to learn how bacterium produce antibiotics by finding out what its genes do They can use this info to improve current production methods Pharmaceutical companies conduct research into ways that microbes cause disease - many make use of receptors or plasma membranes if the receptor site can be blocked - then the disease causing pathogen cannot bind Genomics used to study DNA and compare that of a person with that of a plant/microbe + potential uses in vaccines by sequencing genes in microbes |
|
|
What chemicals does cigarette smoke contain? |
Tar - a mix of chemicals including carcinogens Carbon monoxide Nicotine |
|
|
What are the short term effects of tar? |
1/ Tar settles on lining of airways and alveoli Increases diffusion distance for oxygen entering blood + for CO2 leaving the blood 2/ This presence of chemicals causes allergic reaction - causing smooth muscle to contract and narrowing the lumen and restricting flow of air to alveoli 3/ Tar paralyses cilia on epithelium - so unable to waft mucus out of airway - bacteria and viruses that become trapped aren't removed + multiply in mucus - eventually combo of mucus + bacteria blocks bronchioles makes smokers more likely to get infections like influenza or pneumonia |
|
|
What are the long term effects of tar? |
1/Smokers cough = results from irritation of airways by mucus + bacteria As well as from need to clear airways 4 air to reach alveoli 2/Constant cough - damages delecate lining of airways + alveoli become damaged -lining replaced by scar tissue which is thicker + less flexible (reduces size of lumen or airway) 3/Frequent infections inflames lining which damages it (epithelium) - attracts WBCs and these release enzymes that digest pts of lining to pass through into air spaces (elastase) this damages elastic tissue in lining of small bronchioles + alveoli reduces elasticity of alveolous wall + as we exhale, walls don't recoil to push out air bronchioles collapse trapping air in alveoli which can lead to the alveloli bursting |
|
|
How does tar cause lung cancer? |
Tar contains large no of carcogenic compounds Benzopyrene = 1 of most harmful - these are in tar that lies on delicate surface of lungs These enter cells of lung tissue + take over the genetic material in the nucleus - mutations This causes uncontrolled cell division (which is cancer) Cancers start at entrance to bronchi - as smoke hits fork in airway+ deposits tar - takes 20-30 yrs to develop + may be growing for years before it's discovered |
|
|
What is chronic bronchitis? |
Its the inflammation of the lining of airways - accompanied by damage to cilia and overproduction of mucus - so that it collects up in lungs Symptoms; irritation in lungs, continual coughing, coughing up mucus that's often filled w/bacteria + WBCs leads to increased risk of lung infection |
|
|
What is emphysema? |
Loss of elasticity in alveoli - causing alveoli to burst Lungs have a reduced surface area as larger air spaces are formed Person w/emphysema will often be short of breath, often when exerting themselves Loss of elasticity makes it harder to exhale - in severe cases breathing will become shallow + more rapid Blood is less well oxygenated + fatigue occurs |
|
|
What is COPD? |
Chronic obstructtive pulmonary disease - includes chronic bronhitis, emphysema and asthma |
|
|
What are the symptoms of lung cancer? |
Continual coughing and shortness of breath
Pain in chest Blood coughed up in sputum Blood often first sign that alerts person to the possibility of lung cancer |
|
|
What diseases are nicotine and carbon monoxide linked to? |
Increased risk of cardiovascular diseases; atherosclerosis coronary heart disease stroke |
|
|
What effect does nicotine have on the body? |
Its what causes addiction Nicotine mimics action of transmitter (dopamine) at synapses btwn nerves - making nervous system more sensitive Nicotine causes release of adrenaline -which increases <3 rate and breathing rate, + causes constriction in aterioles -- this leads to extremities of body; reduces blood flow + oxy delivery to extremeties - in extreme cases - amputation is needed Nicotine causes platelets to become sticky - increases risk of a thrombus forming |
|
|
What effect does carbon monoxide have on the body? |
It enters RBCs and combines w/haemoglobin Combines more readily that oxygen - forming carboxyhaemoglobin REDUCES OXY-CARRYING CAPACITY OF BLOOD * smokers feel this during exercisee bc body detects lower level of oxygen + <3 rate may rise Carbon monoxide can also damage lining or ateries |
|
|
How does carbon monoxide lead to atherosclerosis? |
CO damages endothelium of arteries If person has high blood pressure -it adds to it Damage = repaired by action of WBCs - these encourage growth of smooth muscle + deposition of fatty substances Deposits incl cholesterols from LDLs HBP increases deposition of cholesterol - deposits = atheromas Atheromas may incl fibres, dead blood cells + platelets Build up of atheromas occur under endothelium - may grow enough to break through inner lining of artery which eventually forms a plaqure plaque sticks out of lumen of artery -leaving artery wall rougher + less flexible + reduces size of lumen of artery which reduces blood flow |
|
|
How does thrombosis come about? |
Blood flowing past plaque cannot flow smoothly - increasing chance that it will clot - stickiness of platelets increases this chance -if delicate membrane covering plaque is damaged - RBCs also stick to exposed fatty deposits Blood clot = thrombus Sometimes a clot might break free - + be carried to a narrow artery -- then lodges there & stops blood flowing |
|
|
How does coronary heart disease come about?
|
Coronary arteries are prone to damage + atherosclerosis bc the carry blood @ high press When lume or coronary artry is narrowed by plaques - reduces blood flow to <3 muscles ** less oxygen to resire therefore can lead to CHD |
|
|
What three forms does CHD take? |
Angina - severe pain in chest, which may extend down left arm or up into neck Myocardial infarction - death of pt of <3 muscle, usually caused by clot in cor artery blocking flow of blood Heart failure -when <3 cannot sustain it's pumping action; can be due to blockage of major cor artery |
|
|
How does stroke come about? |
Stroke = death of pt of brain tissue - bc of loss of blood flow to that pt of brain Two possible causes of stroke; 1/ blood clot floating around in blood blocks a small artery leading to pt of brain 2/ artery leading to brain bursts (haemorrhage) |
|
|
What are symptoms of atherosclerosis? |
High blood pressure & hypertension - resulting from narrowing of artery lumen -- + deposition of atheroma Artery walls cannot dilate + recoil easily bc atheroma makes it less elastic |
|
|
What is arteriosclerosis? |
Hardening of artery walls making them even less flexible -caused by the deposition of minerals (i.e. calcium) in walls+ atheromas |
|
|
What are the symptoms of coronary heart disease? |
More difficulty exercising Feeling out of breath after exertion Due to oxygen starvation in cardiac muscle - thus doesn't work as hard Angina may occur - sever pain during exercise If isn't treated - can cause <3 failure <3 attack starts slowly and can be confused for indigestion |
|
|
What are the symptoms of a stroke? |
Sudden bc of lack of oxygen reaching brain; 1/ sudden numbness/weakness of face/arm/leg 2/ sudden confusion + difficulty in speaking/understanding 3/ sudden difficulty w/seeing in one/both eyes 4/ sudden trouble w/walking - dizziness, loss of balance or lack of coordination 5/ sudden, severe headache w/no cause |
|
|
What factors increase the risk of developing CHD? |
Age - older age Sex - men more likely to die of CHD under age of 50 Cigarette smoking HBP High blood cholesterol conc Physical inactivity Diet - high level of saturated fats High salt intake Absence of health fats like omega-3 Genetic factors Diabetes Stress Absence of antioxidants like vitamin a,c,e |
|
|
Why isn't CHD more likely to develop in less economically advanced countries? |
Bc inhabitants lead v diff lifestiles - + have a lower life expectancy More likely to suffer or die from other diseases like malaria and HIV Often have a more active lifestyle and diet contains fewer harmful elements Less likely to be heavy smokers bc of economic situation |
|
|
What is a risk factor? |
A factor that increases the chance or risk that a person will develop a disease |
|
|
When did smoking become so widespread? |
Until cigarettes became widely available -shortly after the beginning of the 20th cent Men took up habit during WW1 Number of women who smoked increased during 1940s and 50s - later on in 1900s = became apparent that certain diseases became more common incl lung cancer, chronic bronchitis, emphysema and cardiovascular disease |
|
|
What is epidemiology? |
The study of the distribution of a disease in populations, and factors that influence its spread |
|
|
How has epidemiology been used to study the links between diseases and certain contributory factors? |
Helped to identify: Countries at greater risks Age range of popul at greater risks Which sex is at greater risk Which lifestyle factors may increase/decrease risk |
|
|
What has the info gained from epidemiology been usd to do? |
Help countries/organisations target further spending Help target research at particular risk factors to identify cause/cure Help target screening procedures + find risks early Predict where a disease may become more prevalent in future |
|
|
Epidemiological evidence linking smoking and disease? |
A regular smoker =3x more likely to die prematurely 50% of regular smokes = likely to die of smoking related illness More cigarettes smoked a day - more likely a person is to die prematurely |
|
|
Epidemiological evidence linking smoking to lung cancer? |
Smoker = 18x more likely to develop lung cancer 25% of smokers die of lung cancer heavy smoker is 25x more likely to die of lung cancer than a non smoker chances of developing lung cancer reduce as soon as person stops smoking |
|
|
Epidemiological evidence linking smoking to other lung diseases? |
COPD is rare in non-smokers 98% of people w/emphysema are smokers 20% of smokers have emphysema |
|
|
Epidemiological evidence linking smoking to cardiovascular disease? |
Its known substances in smoke can influence circulatory system - in a way that is likely to enhance atherosclerosis and other circ diseases |
|
|
Experimental evidence showing the links between smoking and disease |
1960s - exps carried out using dogs to test effects of smoking - many dogs attached to devices making them inhale smoke from cigarettes some dogs forced to breath unfiltered smoke these dogs developed changes similar to those of COPD in lungs other groups breathed in filtered cigarette smoke -found they were healthier but lung tissue was developing changes that lead to cancer Suggests filter removed some of substance in smoke = as result further research = carried out on tar collected by filter found it contained substances (carcinogens) like benzopyrene |
