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198 Cards in this Set

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Nourishment- the nutrients needed for health and growth.
Why do we need to eat? Nutrition wise.
Provide better health.
Ensure a stronger immune system.
Mean that you become ill less often.
Help you learn more effectively.
Make you stronger.
Make you more productive.
A balanced diet?
One that contains all the nutrients required for health in appropriate proportions.
When a person is 20% or more heavier than the recommended weight for their height.
These are our main source of energy.
These are essential for growth and repair of muscle and other body tissues.
These are essential as a source of energy and are also important in cell membranes, waterproofing, absorption of fat soluble vitamins.
These play many important roles in the chemical processes taking place inside cells. Some are water soluble and some are fat soluble.
These are the inorganic elements occurring in the body that are essential to its normal function.
This is essential to body function. It is used in the transporting substances around the body and as a main component of the body. About 60% of the human body is water.
Fibre or roughage?
This is the indigestible part of our food. It is essential for healthy functioning of the digestive system.
Mass in kg/(height in m)2
Health risk caused by obesity?
Cancer, cardiovascular disease, type 2 diabetes.
What is obesity also linked to?
gallstones, osteoarthritis, high blood pressure.
Coronary heart disease is result of?
Deposition of fatty substances in the walls of the coronary arteries. This is known as atherosclerosis.
What helps to reduce risk of CHD?
Dietary fibre, moderate alcohol consumption and eating oily fish.
How does excess salt put you at risk?
It decreases the water potential of your blood. As a result more water is held in the blood and blood pressure increases. Can lead to hypertension. Hypertension is when the blood pressure, and particularly the diastolic pressure is maintained at a level that is too high. Hypertension can damage the inner lining of the arteries, which is one of the early stages of atherosclerosis.
Fat (lipids)?
Animals fats tend to be saturated and plant oils tend to be unsaturated. Saturated fats are recognised as more harmful than unsaturated. Polyunsaturated and monounsaturated, such as those found in olive oil, are considered beneficial to health.
Cholesterol in a diet?
Cholesterol is not a triglyceride but it has similar properties. Found in many foods and associated with saturated fats in meat, eggs and dairy products. Cholestrol is also made in the live from saturated fats. Too much is harmful.
Concentration of cholesterol in blood should be..?
5.2mmol dm-3
Why is cholesterol in the blood?
Found in cell membranes and skin. Also used to make steroid sex hormones and bile. Must be transported around the body. Not soluble, so must be converted into something that can be transported in water.
Cholesterol is transported in the blood how?
In the form of lipoproteins. Tiny balls of fat combines with protein. There are two types high density lipoprotein and low density lipoprotein.
Is a state of mental, physical and social wellbeing, not just the absence of disease.
If you are in good health you are...
Free from disease.
Well fed, with a balanced diet.
Usually happy, with a positive outlook.
Suitably housed with proper sanitation.
Well integrated with society.
Able to carry out all the normal physical and mental tasks expected in modern society.
Departure from good health caused by a malfunction of the mind or body.
Definition of disease?
Malfunction of body or mind, which causes symptoms. These symptoms may be physical, mental or social.
Wide range of diseases can be grouped?
They can be grouped into certain categories according to their cause. The diseases caused by living organisms are called infectious diseases. The symptoms are usually physical, but these diseases may have some effects on your mental and social health.
What is a pathogen?
Body creates a good habitat in which microorganisms can live. As a result, there are numerous types of microorganisms that live in or on our bodies. Pathogens cause disease. They live by taking nutrition from the host, and cause damage in the process.
What is protoctisa?
There are a number of diseases caused by animal-like protoctista. Amoeboid dysentary and malaria are two examples. Usually cause harm by entering host cells and feeding on the contents as they grow. Malarial parasite plasmodium has immature forms that feed on the contents of the red blood cells.
What is fungi?
Athletes foot and ringworm are caused by a fungus called tinea. In fact there are number of species that cause these diseases, including species from the genera microsporum, trichophlyton and epidermophyton. The fungus lives in the skin. When it sends out reproductive hyphae, these grow to the surface of the skin to release spores. This causes redness and severed irration.
What is a virus?
Cause a lot of well known diseases including the common cold and influenza. HIV/AIDS is also causes by a virus, and so is the widespread plant disease tobacco mosiac virus (TMV), which affects many plants, including tomatoes. They then cause the cell to manufacture more copies of the virus. The host cell eventually bursts, releasing many new viruses.
What is bacteria?
Cells smaller than our cells, but can reproduce quickly. In right conditions some can reproduce every 20 mins or so. Once in human body can reproduce rapidly. Their presence can cause disease by damaging cells or releasing toxic waste products. Tuberculosis is caused by mycobacterium tuberculosis and mycobacterium bovis.
What are parasites?
Live in or on another living thing. Harm their host. Usually cause by harm by taking nutrients. May live all or part of live on or on host. External parasites, on host. E.g head louse. Internal parasites, in host. e.g tapeworms, in digestive system.
May live unnoticed, better so host does not try to remove. May be a huge burden to host. Can cause damage in which secondary infections are caused by other organisms.
What must a pathogen do to cause disease?
Travel from one host to another.
Get into the hosts tissues.
Cause damage to hosts tissues.
Most common forms of transmission?
By means of vector.
By physical contact.
By droplet infection.
Pathogenic organism transmission?
Once it reaches a new host, pathogens will need to pass through primary defences that the host has to prevent it entry. Once inside the host, the pathogen must overcome any secondary defences or immune responses. Most pathogenic organisms are well adapted to overcoming these obstacles.
Malaria facts?
Malaria kills about 3 million people each year. About 300 million people are affected by malaria worldwide and the number is increasing. Limited to areas in which the vector mosquito, anopheles can survive. This is currently the tropical regions. 90% live in sub sahran africa-(malaria sufferers) With onset of global warming, the anopheles mosquito may soon be able to live further north, and maybe in europe.
Why are diseases important?
Good health is a human right. Poor health causes a lot of suffering. Ill health also has a economic cost as a result of the need to provide medical service, and due to loss of productivity.
In less economically developed countries, the following aspects may contribute to poor health...
Lack of proper shelter.
Lack of purified water.
Poor nutrition.
Poor hygiene.
Lack of investment by government.
Poor or inadequate health services.
civil unrest or warfare.
inadequate education about diseases.
inadequate transport facilities.
HIV/AIDS facts?
Still spreading in pandemic proportions. 45 million people living with it at end of 2005.
More than half in sub saharan Africa.
5 Million people are newly infected.
By end of 2005 nearly 30 million people had died from HIV/AIDS-related diseases.
By 2006/07 HIV/AIDS was spreading rapidly in China, Russia and other eastern european countries.
Tuberculosis Facts?
WHO declared it a public health emergency in 1993.
Cases rose steadily each year.
1% of world population newly infected each year, and 10-15% of those go on to develop the disease.
Tb peaked in 2004 and held steady in 2005. In 2005 8.8 millions new cases were recorded and 1.6 million people died.
30% of worlds population may be infected with mycobacterium, and new threats of strains that are resistant to most of drugs avaliable.
Food production more efficient in plants?
Improve the growth rate of crops.
Increase the size of yield from each plant.
Reduce losses of crops due to diseases and pests.
Make harvesting easier by standardising plant size.
Improve plant responses to fertilisers.
Food production more efficient in animals?
Improve the rate of growth.
Increase productivity.
Increase resistance to disease.
Selective breeding?
Where humans select the individual organisms that are allowed to breed according to chosen characteristics.
Minerals needed for plant growth, which are added to soil to improve fertility.
A pesticide?
Chemical that kills pests.
A fungicide?
Chemical that kills fungi.
An antibiotic?
Chemical that kills or prevents reproduction in bacteria.
Three stages of selective breeding?
Artificial selection.
Inbreeding or line breeding.
Artificial selection?
Breeding animals with desirable traits and that over time, such breeding exaggerated small diffferences.
Examples of marker assisted selection?
Tomatoes have been bred with improved disease resistance. A wild tomato variety with good resistance to yellow leaf curl virus, which can devastate domesticated tomatoes, was found. The allele responsible for resistance was identified and bred into a domestic variety.

Apples have been bred with improved disease resistance, and work is continuining to develop varities with improved flavour and texture.
What is marker assisted selection?
A section of DNA is used as a marker to recognise the desired characteristic. Once offspring have been produced from the selected parents, their DNA is checked for the marker. This allows selection at a very early stage.
Eat both plants and animals.
Gain nutrition directly from plants and indirectly from animals. Humans food chain tends to be short.
Selection pressure?
Selecting of which farm animals are allowed to breed and which seeds to save for sowing the following year.
What do fertilisers do?
They replace minerals in the soil. These minerals may have been removed by previous crops. Fertilisers containing nitrate, potassium and phosphate are the most common, They increase rate of growth and overall size of crops.
What do pesticides do?
Designed to kill organisms that cause disease in crops. These diseases would reduce the yield or kill the crop. Many crops are sprayed with fungicides to reduce the effect of fungal growth in leaves or roots. Sheep are usually dipped to kill ticks.
What do antibiotics do?
Reduce the spread of disease among animals that are intensively farmed and in close proximity to each other. Such diseases could reduce the growth performance of the animals and may impair reproduction.
Examples of selective breeding?
Chickens are bred for egg production or meat production. Egg-layers can produce over 300 eggs a year.
Farmers breed cattle for high milk yield or for meat production. Dairy cows can produce over 40 litres of milk a day.
Farmed salmon have been selected to grow more quickly so that time-to-market has been cut by 30%. At the same time, the disease resistance and meat quality have been improved.
High density lipoproteins?
Unsaturated fats, cholesterol and proteins.
Carry cholesterol from body tissues back to liver.
Liver cells have receptor sites that allow HDLs to bind to their cell surface membrane.
What does the liver do with the cholesterol?
used in cell metabolism or broken down.
What are levels of HDLs associated with?
Reducing blood cholesterol levels. They reduce deposition in the artery walls by atherosclerosis.
Low density lipoproteins?
Saturated fats, cholesterol and protein.
Carry cholesterol from liver to body tissues.
Tissue cells have receptor sites that allow LDLs to bind to their cell surface membranes.
What does a high concentration of LDLs cause?
Causes deposition in the artery walls.
What do saturated fats do?
Decrease the activity of the LDL receptors. Therefore as blood LDL concentration rises, less is removed from the blood.
What do polyunsaturated fats do?
Increase the activity of the LDL receptors and so decrease the conc of LDL in the blood.
Diet and lipoproteins?
Eating a low fat diet with reduce overall concentration of lipoproteins.
High proportion of unsaturated fats will increase the proportion of HDLs in blood.
Eating polyunsaturated fats help to reduce the conc of LDLs in blood as do monounsaturated fats.
Advs of using microorganisms?
Production of protein can be many time faster that that of animals or plants proteins.
There are no animals welfare isuses.
They provide a good source of proteins for veggies.
The protein contains no animals fat or cholesterol.
SCP production could be combines with removal of waste products.
Production can be increased and decreased subject to demand.
Disadvs of using microorganisms?
Palatability- does not have taste or texture of traditional proteins sources.
Infection- Conditions needed for the useful microorganisms to grow are also ideal for pathogenic microorganisms.
Protein has to be purified.
Isolation of protein- need to be isolated from material on which they grow.
Food spoilage-cooking?
The heat denatures enzymes and other proteins and kills the microorganism.
Food spoilage-pasteurising?
Involved heating to 72 degrees for 15 seconds and then cooling rapidly to 4 degrees.
Food spoilage- Drying, salting and covering in sugar?
Dehydrates as water leaves my osmosis.
Food spoilage- Smoking?
Food develops a hardened, dry outer surface, and smoke contains antibacterial chemicals.
Food spoilage- Pickling?
Uses an acid pH to kill microorganisms bu denaturing their enzymes and other proteins.
Food spoilage- irradation?
Ionising radiation kills the microorganisms by disrupting their DNA structure.
Food spoilage-cooling and freezing?
They do not kill microorganisms, but retard enzyme activity so their metabolism, growth and reproduction is slow.
Other methods to prevent contamination?
Canning, vacuum wrapping and any plastic or paper packaging.
Spoilage of food- visible growth?
Most obvious when fungi grow on food. For example colonies of the moulds mucor and penicillium often grow on bread.
Spoilage of food- external digestion process?
Release enzymes into the food and absorb the nutrients released by breakdown of the food molecules. When this happens, food often smells sweet as sugars are released from carbohydrate molecules.
Spoilage of food- toxin?
Bacterium clostridium botulinum produces a toxin called botulin. This causes botulism. If these bacteria are growing on food, the toxin will be present. One of the most toxic substances known, as little as ug can kill a person.
Spoilage of food- Infection?
Salmonella bacteria, sometimes present in poultry products, attack the lining of the stomach and digestive system.
Using microorganisms to make yoghurt?
It is milk that has been affected by lactobacillus bacteria. Lactose sugar is made into lactic acid, causing the milk to thicken.
Bacteria partially digest milk, making it easily digestible by humans.
Using microorganisms to make cheese?
Made from milk that has curdled. Solid portion of milk is acted on by lactobacillus bacteria. The cheese can be given additional flavour by contamination with fungi such as penicillium,
Using microorganisms to make bread?
Made to rise by yeast, which respires anaerobically to release carbon dioxide, Bubbles of the gas collect in the dough causing it to rise.
Using microorganisms to make alcohol?
Cereal grains containing the sugar maltose can be used to brew beer, as the yeast respires the sugar.
Single celled protein?
Microorganisms used to manufacture proteins that is used directly as food.
A protein made by fungus.
How can HIV be transmitted?
Exchange of fluids, such as blood to blood contact.
Unprotected sexual intercourse.
Unscreened blood transfusion.
Sharing hyperdermic needles.
Accidents such as 'needle sick'
From mother to baby during breast feeding.
Across the placenta or during childbirth.
use of unsterilised medical equipment.
What is malaria caused by?
Eukaryotic organism from genus plasmodium.
Plasmodium falciparum is most widespread. P.vivax, P. ovale and P. Malarie can also cause it.
How is malaria spread?
Spread by a vector. The female anopheles mosquito carries the plasmodium from and infected person to an uninfected person. They feed on blood. Mouthparts are adapted to a fine tube or proboscis.
Malarial parasites lives in the red blood cells of the human host and feed on haemoglobin.
HIV/AIDS caused by?
Human immunodeficiency virus.
Virus enter body and may remain intact.
Once active it attacks and destroys T helper cells in the immune system. These cells normally help to prevent infection.
May contact a range of opportunistic infections.
What is TB caused by?
A bacterium. Two species- Mycobacterium tuberculosis and M.Bovis.
Can affect may parts of the body, but usually found in lungs.
How is TB transmitted?
By droplet infection. Though 30% of worlds population is infected, in many people it is inactive or controlled by immune system.
What conditions make TB spread more quickly?
Poor ventilation.
Poor health.
Poor diet.
Living or working with people who have migrated from areas where TB is more common.
TB transmission detailed?
Bacteria are contained in tiny droplets of liquid that are released from infected person. If you inhale those droplets, you become infected. However it takes close contact over a long time.
What are the 3 harmful substances in cigarettes?
Tar, carbon dioxide and nicotine.
Primary defences?
Those that attempt to prevent pathogens from entering the body.
Immune response?
Specific response to a pathogen, which involved the action of lymphocytes and the production of antibodies.
Other primary defences?
Eyes are protected by antibodies in the tear fluid.
Ear canal is lined with wax, which traps pathogens.
Vagina is protected by maintaining relatively acidic conditions.
Molecules that stimulate an immune system.
Protein molecules that can identify and neutralise antigens.
An antibody is specific to a particular antigen because of the shape of the variable region. Each type of antibody has a differently shaped variable region.
You recognise these cell by their multilobed nucleus. They are manufactured in bone marrow. Travel in blood and usually squeeze out blood into tissue fluid. May also be found on epithelial surfaces such as lungs, Short-lived but will be released in large numbers as a result of infection.
Why are new drugs needed?
New diseases are emerging.
There are still many diseases from which there are no effective treatments.
Some antibiotics are becoming less effective, as they are becoming resistant.
How are drugs discovered, by accident?
Accidental discovery of penicillin is well documented. Most antibiotics currently in used are made by bacterium streptomyces.
The antibiotics neomycin, chloramphenicol and strepomycin are made from streptomcyes.
Chronic bronchitis?
Inflammation of the lining of the airways. This is accompanied by damage to the cilia and the overproduction of mucus, so that mucus collects in the lungs. Symptoms are irratation in the lungs, continual coughing, and coughing up mucus that is often filled with bacteria and white blood cells.
Chronic obstructive pulmonary disease?
COPD is a combination of diseases that include chronic bronchitis, emphysema and asthma. Symptoms are a combination of those.
Lung cancer?
Can be recognised by continual coughing and shortness of breath. There may be pain in the chest and blood coughed up in the sputum, This blood is often the first sign.
Chemicals that cause cancer.
Loss of elasticity in the aveoli, which causes them to burst. Lungs have a reduce surface area, as large air sacs are formed. Less surface area for gaseous exchange. Short of breath. Harder to exhale. Blood is less well oxygenated and fatigue appears.
Long term effects of smoking- smokers cough?
It is an attempt to shift the bacteria laden mucus that collects in the lungs. It results from the irritation of the airways by the mucus and bacteria, as well as from the need to clear the airways in order to get air down the alveoli.
Longer term effects of smoking- consequence of smokers cough?
Delicate lining of the airways and aveoli can become damaged. Lining will eventually be replaced by scar tissue, which is thicker and less flexible.
Layer of smooth muscle thickens. This reduces the lumen of the airway and flow of air is permanently restricted.
Longer term effects of smoking- constant infection?
Inflames the lining of the airways. Damages lining and in particular epithelium. Attracts white blood cells. White blood cells release enzymes, enzymes digest part of the lining of the lungs in order to pass through the air spaces. This damages elastic tissue in lining of lungs.
Can reduce elasticity of alveolus wall, they dont recoil and push air out, bronchioles collapse and aveoli burst due to pressure.
Shorter term effects of smoking- blocking of bronchioles?
Bacteria and viruses that become trapped in the mucus are not removed. They can multiply in the mucus and eventually a combination of mucus and bacteria block it.
Shorter term effects of smoking- infection?
Prescence of bacteria and viruses means that the lungs are more susceptible to infection. More likely to catch diseases.
Shorter term effects of smoking- paralysis of cilia?
Tar paralyses of destroys cilia on the surface of the airways, so they are unable to move the layer of mucus up and down the throat. tar also stimulates goblet cells and mucus secreting glands to enlarge and release more mucus.
Shorter term effects of smoking- allergic reactions?
Many chemicals in the tar lying on the surface of the airway may cause an allergic reaction. Causes the smooth muscles in the walls of the airways to contract. Lumen of airways gets smaller and restricts the flow of air to the aveoli.
Shorter term effects of smoking- diffusion distance?
Tar is a combination of chemicals that settles on the lining of the airways and aveoli. This increases the diffusion distance for oxygen entering the blood and for carbon dioxide leaving the blood.
Deposition of fatty substances in the walls of the arteries.
What three cardiovascular diseases risks are increased, when you smoke?
Coronary heart disease
Carbon monoxide?
Enters the red blood cells and combines with the haemoglobin. It combines more readily than oxygen and forms the stable compound carboxyhaemoglobin. Reduces the oxygen carrying capacity. May cause heart rate to rise. Can damage lining of arteries.
Is the death of part of the brain tissue. It is caused by the loss of blood flow to that part of the brain. This happens very suddenly. Two possible causes:
A blood clot (thrombus) floating around in the blood blocks a small artery leading to the brain.
An artery leading to the brain bursts.
Affects platelets to make them sticky. Increases risk of blood clot or thrombus.
Causes constriction of arteioles leading to extermities of body. Reduces blood flow and oxygen delivery.
Mimics the action of transmitter substances at the synapses between nerves, makes nervous system more sensitive.
Causes release of hormone adrenaline, Increases heart rate and breathing rate.
Blood flowing past plaque cannot flow smoothly. Increases chance it will clot. Stickiness of platelets increases this. If delicate membranes that covers the plaque is damaged, red blood cells also stick to exposed fatty deposits. Clot in artery may stop the blood flow.
White blood cells encourage growth of smooth muscles and the deposition of fatty substances.
Deposits include cholesterol from LDL. High blood pressure also increases the deposition. Deposits (atheromas), may also contain fibres, dead blood cells and platelets.
Build up occurs under endothelium, in wall of artery, eventually forms a plaque which sticks to lumen of artery. Leave artery wall rougher and less flexible.
What factors increase the risk of CHD?
Age, sex, cigarette smoking, obesity, high blood pressure, high blood cholesterol, physical inactivity, diet, high salt intake, absence of healthy fats, genetic factors, absence of antioxidants, stress, diabetes.
Risk factor?
Factor that increase the chance or risk that a person will develop a diseases.
Symptoms of stroke?
Sudden numbness or weakness of the face, arm or leg.
Sudden confusion and difficulty in speaking.
Sudden difficulty with seeing.
Sudden trouble with walking.
Sudden severe headache.
Links to lung cancer?
A smoker is 18 times more likely than a non smoker to develop lung cancer.
25% of smokers die of lung cancer.
A heavy smoker is 25 times more likely than a non smoke to die of lung cancer.
The chance of developing lung cancer reduces as soon as a person stops smoking.
Links to other lung diseases?
Chronic obstructive pulmonary disease is rare in non smokers.
98% of people with emphysema are smokers.
20% of smoker has emphysema.
Epidemiologists and links to smoking?
A regular smoker is three times more likely to die prematurely than a non smoker.
50% of regular smoker are likely to die of a smoking related disease.
More cigarettes a person smokes per day, they more likely they will die prematurely.
What is epidemiology?
Study of the distribtuon of a diseases in populations, and the factors that influence its spread.
Epidemiology can help to identify?
Which countries may be at greater risk.
Which age range of the population may be at a greater risk.
Which sex may be at a greater risk.
Which lifestyle factors may increase of decrease risk.
Information gained from epidemiology can be use to?
Help countries or organisations target further spending.
Help target research at particular risk factors to find a cause or cure.
Help target screening procedures and find those at risk early.
Help target advice and education at the parts of the population most at risk.
Predict where a disease might become more prevalent in the future.
Target geographical areas at risk.
Check how well campaigns and preventative measures.
Links to cardiovascular disease?
Not easy to link. So many risk factors contributing to CD. Known that substances released in cigarette smoke can influence the circulatory system in a way that is likely to enhance it.
Experimental evidence- unfiltered smoke?
These dogs developed changes in their lungs that were similar to those of COPD. They also developed early signs of lungs cancer.
Experimental evidence- filtered smoke?
These dogs remained healthier, but further analysis of their lung tissue showed that some cells were developing changes that lead to cancer.
What did experimental research suggest?
Filtered removed some of the substances in smoke that are particularly harmful. Further research on tar collected in filter revealed carcinogens and was tested on mice, and they developed skin cancer.
Are larger cells manufactured in the bone marrow. They travel in the blood as monocytes. They tend to settle in the body organs, particularly in the lymph nodes. Here they develop into macrophages. Also play and important role in the specific responses to invading pathogens.
Phaogcytes engulf and destroy pathogenic cells?
When a pathogen invades the body, it is recognised as foreign by the chemical markers on its outer membrane.
What are the markers called?
Antigens? Phagocytes?
Antigens are specific to the organism, Our own cells have antigens but these are recognised as our own and do not produce a response.
What happens once the phagocytes is bound to the pathogen?
It will envelop the pathogen by folding its membrane inwards. The pathogen is trapped inside a vacuole called a phagosome. Lysosomes fuse with it and release enzymes. Enzymes called lysins and digest the bacterium. Neutrophils are short lives and will die soon after digesting a few pathogens. May collect o form pus in area of infection.
How phagocytes work? Protein in the blood..
Called antibodies attach to the foreign antigens. Phagocytes have membrane-bound proteins that act as receptos. The receptors binds to the antibodies already attached to the pathogen, this process may be assisted by other proteins called opsonins.
What do infected cells do?
Release chemicals such as histamine, which attracts neutrophils to the area, and histamine causes the capillaries more leaky.
What happens when the capillaries become more leaky?
More fluid leaves the capillaries in the area of infection. This causes swelling and redness, but also means more tissue fluid passes into the lymphatic system. This leads the pathogens towards the macrophages waiting in the lymph nodes.
Immune response, detailed?
Macrophages initiate specific response to a disease. Immune response is activation of lymphocytes in the blood to help fight the disease.
Structure on an antibody?
Four polypeptide chains held together by disulphide bridges.

A constant region, which is the same in all antibodies. Enables the antibody to attach to phagocytic cells and helps in the process of phagocytosis.

Hinge regions, which allow a certain degree of flexibility. These allow the branches of the Y-shaped molecule to move further apart in order to allow attachment to more than one antigen.

A variable region, which has a specific shape and differs from one type of antibody to another. This is the result of its amino acid sequence. It ensures that the antibody can only attach to the correct antigen.
About antibodies?
Molecules produced by the lymphocytes in the immune system. Released in response to infection. Large proteins also known as immunoglobulins. Specific shape that is complementary to that of a particular antigen.
Antibodies are specific to certain antigens. Immune system must manufacture one type of antibody for every antigen. Antibodies attach to antigens and render them useless.
About Antigens?
Molecules that stimulate an immune response. Almost any molecule could act as an antigen. Large molecules with specific shape. Foreign antigen will be detected by immune system and will stimulate the production of antibodies. Antigen specific to pathogen. Antigens usually a protein or glycoprotein in or on plasma membrane.
Why are antibodies produced?
Produced in a response to infection. When an infecting agent is first detected, the immune system starts to produce antibodies.
Primary immune response?
Takes a few days before the number of antibodies in the blood rises to a level that can combat the infection successfully. Once the pathogens have been dealt with, the number of antibodies in the blood drops rapidly.
Secondary immune response?
Antibodies do not stay in the blood. Antibodies must be made again. Immune system can swing into action more quickly. This time production of antibodies starts sooner and is much more rapid. Conc rises sooner and reaches higher conc.
How do antibodies work?
Antibodies work by attaching to the antigens on a pathogen. Antigen is a molecule on the cell surface membrane of the pathogen. Pathogen may have another use for this molecule. It may be a binding site, which would be used to bind to host cell. If the antibody blocks the binding site, the pathogen cannot bind to its host cells. This is call neutralisation.
Antibodies Larger than Y-shaped molecules?
They resemble several y-shaped molecules attached together, and have many specific variable regions. Each variable region can act as a binding site to bind to an antigen on a pathogen. If the antibody has a number of binding sites, it may be able to attach to a number of pathogens at the same time, this is called agglutination. When the pathogens are stuck together, they cannot enter the hosts cells.
Cell signalling?
Communication between cells that allows effective coordination of a response.
Information communicated- identification?
The first signalling is actually done by the pathogen. The pathogen carries antigens on its cell surface. These act as flags or makers that say 'im foreign'. These are detected by our body cells.
Identification communicated- Sending distress signals?
When body cell is infected by a pathogen, it is usually damaged in some way. The internal cell organelles such as lysosomes will attempt to fight the invader. Number of pathogens damaged. Parts of pathogen often end up attached to host plasma membranes
Two effects:
1. They can act as a distress signal and can be detected by cells from the immune system.
2. They can act as markers to indicated that the host cell is infected- T killers can recognise that the cell is infected and must be destoryed.
Information is communicated- Antigen presentation?
Macrophages in the lymph nodes act like phagocytes to engulf and digest the pathogen. Do not fully digest it. Separate out the antigens and incorporate them into a cell surface molecule. Exposed on the surface of the macrophage, which is known as an antigen presenting cell. Function to find lymphocytes that can neutralise that particular antigen.
Information is communicated- Instructions?
Cytokines released by cell. Chemical signals act as instructions to their target cells. Act over short distance at very low conc. Act by binding to specific membrane bound receptors on the target cell. Release of second messengers inside the cell, which alters its behaviour through gene expression.
How does communication using cytokines occur?
Macrophages release monokines that attract neutrophils ( by chemotaxis- the movement of cells towards a particular chemical)
Macrophages release monokines that can stimulate B cells to differentiate and release antibodies.
T cells, B cells and macrophages release interleukins, which can stimulate proliferation and differentiation of B and T cells.
Many cells can release interferon, which can inhibit virus replication and stimulate the activity of T killer cells.
Memory cells?
Cells that circulate in the blood after an immune response. They speed up the response to a subsequent attack by the same pathogen.
White blood cells that circulate around the body in the blood and lymph. B cells mature in the bone marrow, White T cells originate in the bone marrow but mature in the thymus gland.
T lymphocytes develop or differentiate into three types of cells?
T helper cells, which release cytokines that stimulate the B cells to develop and stimulate phagocytosis by the phagocytes.
T Killer cells, which attack and kill infected body cells.
T memory cells.
The B lymphocytes develop into two types of cell?
Effector or plasma cells, which flow around in the blood, manufacturing and releasing the antibodies.
B memory cells that remain in the body for a number of years and act as the immunological memory.
How is communication between cells achieved?
Achieved through cell surface molecules and through the release of hormone like chemicals called cytokines.
In order to detect a signal, the target cell must have a cell surface receptor.
B lymphocytes and T lymphocytes receptors?
Have receptors that are complementary in shape to the foreign antigen. The antigen may be an isolated protein, it may be attached to a pathogen, or it may be on the surface of a host cell. When the antigen is detected, the lymphocyte is activated or stimulated. Chemical signals are also detected by their target cells using specialised cell surface receptors.
A vaccination?
Deliberate exposure to antigenic material, which activates the immune system to make an immune response and provide immunity.
Ring vaccination?
Used when a new case of disease is reported. Ring vaccination involved vaccinating all the people in the immediate vicinty of the new case. This may mean vaccinating the people in the surrounding houses, or even the whole village or town. Ring vaccination is used in many parts of the world to control the spread of livestock disease.
Natural immunity?
Gained in the normal course of living processes. It may be gained as a result of infection that stimulates an immune response.
Artificial immunity?
Gained by deliberate exposure to antibodies or antigens.
Active immunity?
Immunity that is achieved by activation of the immune system. Lymphocytes in the body manufacture antibodies and release them into the blood. This form of immunity can usually last for many years or even a lifetime.
Passive immunity?
Provided by antibodies that have not been manufactured bu stimulating the recipients immune system. Antibodies may be provided by a mother across the placenta or via breast milk. Antibodies can also be provided by intravenous injection. This form on immunity is often short lived.
Antigenic material forms?
A dead pathogen.
Some harmless toxin.
A preparation of the antigens from a pathogen.
A harmless of attenuated version of the pathogenic organism,
Whole, live microorganisms- usually ones that are not as harmful as those that cause the real disease. But they must have very similar antigens so that the antibodies produced will be effective against the real pathogen.
Herd vaccination?
Using a vaccine to provide immunity to all or almost all of the population at risk.
Essential to vaccinate almost all population. To eradicate smallpox it was necesscary to vaccinate 80-85% of the population.
What happens to a person that has been vaccinated?
Has artificial active immunity.
Created as deliberate exposure to antigenic material that has been rendered useless.
Treats antigenic materials as a real disease. Immune system manufactures antibodies an memory cells. Memory cells provide the long term immunity.
Natural Passive Immunity?
Antibodies provided via breast milk. This makes the baby immune to diseases that the mother is immune to. It is very useful in the first year of the babies life, when its immune system is developing.
Natural active immunity?
Immunity provided by antibodies made in the immune system as a result of infection. A person suffers from the disease once and is then immune.
Artificial passive immunity?
Immunity provided by injection of antibodies made by another individual.
Artificial active immunity?
Immunity provided by antibodies made in the immune system as a result of vaccination. A person is injected with a weakened, dead or similar pathogen, or with antigens, and this activates his/her immune system.
Killer disease cause by a virus. Affects the respiratory system. People over 65 and people with respiratory tract conditions are particularly at risk.
New strains arises, which may cause a pandemic.
1918 flu epidemic killed at least 40 million people worldwide.
Such a large scale outbreak of a disease is called a pandemic.
In attempt to avoid another pandemic?
People may be immunised. In the UK there is a vaccination programme to immunise all those aged over 65 and those who are at risk for any another reason. In 2006/07 about 74% of people over 60 were vaccinated along with about 42% of younger people in at risk groups.
The skin?
Outer layer called epidermis. Epidermis consists of layers of cells. Most of these cells are called keratinocytes. Cells are produced by mitosis at base of epidermis.
They then migrate out to the surface of the skin. As they migrate, they dry out and cytoplasm is replaced by the protein keratin.
Process is called keratinisation. Take about 30 days. By the time the cells reach the surface, they are no longer alive. Eventually dead cells slough off. Keratinsed layer of dead cells acts as an effective barrier.
Mucous membranes? Goblet cells?
Epithelial layers contain mucus secreting cells called goblet cell. In the airways the mucus lines the passages and traps any pathogens that may be in the air.
Mucous membranes? Ciliated cells?
The cilia are tiny, hair like organelles that can move. They move in a coordinated fashion the waft the layer of mucus along.
Moves mucus up to the top of the trachea, where it can enter oesphagus. It is swallowed and passes down the digestive system. Most pathogens in the digestive system are killed by the acidity of the stomach, which can be pH 1-2. This denatures the pathogens enzynes,
Where are mucous membranes found?
Gut, genital areas, anus, ears and nose.
How are new drugs discovered- anaesthetics?
The sap of unripe poppies was used in Neolithic times in parts of Southern Europe and Egypt. In the twelfth century opium from poppies was used as an anaesthetic and by the ninteenth century morphine and opium was being used. These opiate drugs reduce nervous action in the central nervous system. If the nerved cannot carry impulses, no pain is felt.
How are new drugs discovered- Traditional medicine?
Many drugs have been used for centuries. WHO calculates that 80% of the worlds population relies on traditional medicines. In India some 7000 different plants are used for their medicinal properties, and in China they use about 5000 different plants. In Europe, too, some of our modern drugs have their origins in traditional medicine.
How are new drugs discovered- modern research?
Scientists have used traditional plant medicines and animal behaviour as a starting point in their search for new drugs. Research into the plants used allows them to isolate the active ingredient.
How are new drugs discovered- observation of wildlife?
Monkeys, bears and other animals rub citrus oils on their coat as insecticides and antiseptics to prevent insect bites and infection.
Elephants roam miles to find clay to counteract dietary toxins.
Birds line their nests with medicinal leaves to protect chicks from blood sucking mites.
Chimpanzees swallow leaves folded in a particular way to remove parasites from their digestive tract.
The hunt is on- natural medicines?
Discovery of natural drugs has concentrated on tropical drugs. Many potential uses of wild and cultivated plants in the UK. New chemical fingerprinting technology is enabling scientists to screen natural chemicals more effectively for their activity as potential medicines.
Differentiation- taking time?
Each process takes time. The correct lymphocytes must be selected. The cells must divide to increase in number. They must differentiate into plasma cells. The plasma cells must manufacture the antibodies. All this means that it may be a few days before the number of antibodies in the blood starts to rise.
Example of aspirin?
Willow bark to relieve pain and fever. In 1828 the active ingredient salicin was extracted. Relieved pain by causes stomach bleeding. Acetyl group was added to reduce this side effect.
Salicin works by inhibiting enzymes involved in the synthesis of prostaglandins. Hormone like substances that have a variety of roles in cell communication.
Detection by T and B lymphocytes to trigger immune response?
Lymphocytes carry the correct receptor molecules on their membranes. The receptor molecules are cell surface proteins that have a shape that is complementary to the shape of the antigen. Once the correct T or B lymphocytes detect the antigens, the immune response can begin.
Clonal selection?
The selection of the correct B and T lymphocytes.
Clonal expansion?
Before they can become effective in fighting the pathogen, these lymphocytes must increase in numbers. The lymphocytes divide by mitosis a number of times.
Advanced cases of CHD cause?
Angina, which is a severe pain in the chest felt , during exercise. A heart attack often felt as a severe and disabling pain in the chest and arm. May feel as if a tight band has been placed around the chest. May lead to heart failure.
Symptoms of CHD?
Find it more difficult to exercise, and out of breath easily. Due to atherosclerosis in coronary arteries.
narrow lumen, reducing blood flow.
Heart needs to increase output.
Put under strain as does not have sufficient oxygen.
Symptoms of cardiovascular disease?
High blood pressure and hypertension. Result from narrowing of the artery lumen caused by deposition of atheroma.
Increases friction between the blood and artery wall.
Artery walls less elastic.
Cannot dilate and recoil easily.
Ateriosclerosis hardens the walls and makes them even less flexible.