Health and Disease What your syllabus says Prescribed Focus Areas 5.1explains how social factors influence the development and acceptance of scientific ideas 5.3evaluates the impact of applications of science on society and the environment 5.5analyses how current research might affect peoples lives Knowledge 5.12technology b) Discuss the benefits and problems associated with medical and industrial uses of nuclear energy describe some medical applications of electromagnetic radiation relates the structure and function of living things to models, theories and laws Humans a) Describe the role of, and interaction between, coordination systems in maintaining humans as functioning organisms b) Describe some responses of body systems to infectious and non-infectious diseases Skills Choosing equipment or resources Describe ways to reduce the risk to themselves and others when working in the laboratory or field Performing first-hand investigations follow the planned procedure when performing an investigation safely and efficiently construct, assemble and manipulate identified equipment g) record data using the appropriate units 5.16accesses information from a wide variety of secondary sources 5.17explains trends, patterns and relationships in data and/or information from a variety of sources 5.18selects and uses appropriate forms of communication to present information to an audience 5.19uses critical thinking skills in evaluating information and drawing conclusions Focus Verbs Identify Describe Explain Discuss outline Spelling Vaccine Infectious Health Antibody Disease Virus Traditional Immune Pathogen Bacteria Medicine System Lets Make a Glossary Construct a table that will show the terms and their meanings used in the spelling list. You will add to this glossary throughout the topic. Glossaries are a very useful tool for studying for exams because they let you define terms in your own words clearly in questions and know what key words you can use instead of being conversational in your answers. This will help you to get better marks in your School Certificate. Disease The study of disease is called pathology and people working in this field are called pathologists. A disease is defined in biology as anything that stops the body functioning properly. This does not only include the flu, but also other conditions such as colour blindness. NOW add these to your glossary Other definitions you will need to remember are : An organism is any living thing. An organism is any living thing. A micro-organism (often called a microbe) is a very small organism that cannot be seen with the naked eye but can be seen using a microscope. Some micro-organisms consist of only one cell. A micro-organism (often called a microbe) is a very small organism that cannot be seen with the naked eye but can be seen using a microscope. Some micro-organisms consist of only one cell. An pathogen is an organism that causes disease. An pathogen is an organism that causes disease. A host is the organism being affected by the pathogen. A host is the organism being affected by the pathogen. A parasite is a pathogen that uses the host for food and/or shelter and has a negative effect on the host. A parasite is a pathogen that uses the host for food and/or shelter and has a negative effect on the host. An infection is where a pathogen enters the body and is able to cause disease. The pathogen will multiply and have numbers that are so large that symptoms will show. An infection is where a pathogen enters the body and is able to cause disease. The pathogen will multiply and have numbers that are so large that symptoms will show. SYMPTOMS are the physical effects on the body by a disease. These can include fever, increased sweating, a rash, coughing etc. INCUBATION PERIOD is the time between entry of the pathogen and the development of symptoms. Some diseases have short times, such as influenza and ebola. Others have longer times, such as up to 3 weeks with Chickenpox. This can be a problem because the hosts can be spreading the disease before they know they have it. TRANSMISSION is the passing of disease from one person to another. Virulence is a measure of how much damage a disease does to the host. Highly virulent diseases cause very serious symptoms, perhaps death. Virulence is a measure of how much damage a disease does to the host. Highly virulent diseases cause very serious symptoms, perhaps death. Can you think of some examples? Endemic means that a disease regularly affects a small number of people in the population. What examples do you know of ? An epidemic is when there are higher than normal numbers of people being affected by a particular disease in a certain place. An epidemic is when there are higher than normal numbers of people being affected by a particular disease in a certain place. A pandemic is when an epidemic spreads across countries. This was recently an issue with the SWINE FLU, and then the Avian Influenza (Bird Flu) before that. PFA:5.1 The history of science Describe historical cases where developments in science have led to the development of new technologies Universal Flu Vaccine digital article including videoclip. Causes of Disease Disease can be caused by many factors, some infectious, some avoidable and others you are born with. INFECTIOUS DISEASES The body could be infected by micro-organisms such as bacteria, viruses, protozoa and fungi. These diseases are classified as infectious. The body could be infected by micro-organisms such as bacteria, viruses, protozoa and fungi. These diseases are classified as infectious. Parasites such as worms, ticks and lice can be transmitted from other infected people. These would then infect the new host.. Parasites such as worms, ticks and lice can be transmitted from other infected people. These would then infect the new host.. A Summary of Infectious Diseases Caused by organisms called PATHOGENS. Infect a host Can be TRANSMITTED (passed on) from one host to another via faeces, breath droplets, water supplies, utensils etc. Pathogens include viruses (eg Influenza), bacteria (eg Tetanus), fungi (eg Tinea), protozoans (eg Giardia) and parasites such as worms, ticks and lice. Lets Look at Some Pathogens. Using the Microscope COMPARE the structures of different pathogens. You will need to draw and label what you observe for each pathogen and include some description as well. What is the best way to present these results? DRAWING SCIENTIFIC DIAGRAMS Always include a title/heading for each one stating what the specimen is and the magnification used to view it. Use lead pencil!!!! Make the diagrams large enough to be seen clearly. Drawings need to be 2D and not be furry or sketchy but have clear lines. Labels must be included in all diagrams but do NOT use arrows to connect the label to the structure. Scenario of a Fictitious Infectious Disease /Content/L2019/object/sc_004_clt_750//Content/L2019/object/sc_004_clt_750//Content/L2019/object/sc_004_clt_750/ NON INFECTIOUS DISEASES Some part of the body could malfunction due to some imperfection or fault. Some part of the body could malfunction due to some imperfection or fault. For example, diabetes can develop if the pancreas isnt working properly. This is called physiological malfunction. Environmental factors might cause your body not to function properly. Environmental factors might cause your body not to function properly. Heavy Metals in soil and water pollution, can cause disorders such as lead poisoning and Minamata Disease,with Mercury,in Japan. Cataracts are caused by normal but still damaging exposure to UV radiation) and not wearing proper sunglasses. Lifestyle factors can also cause disease. These factors are self-inflicted and include drug abuse, overuse of alcohol, smoking, sunbaking and high-fat, high- sugar diets. Diseases such as lung cancer, melanaoma and heart disease can be classified as lifestyle diseases. Genetic disorders or diseases are passed on from parents to their offspring. The parents either had or carried the genes for the disease. Sometimes these diseases are due to mutations or changes in the structure of the parts that make up chromosomes. These small parts are called genes and can be changed through radiation, Xrays and chemicals or can be due to other factors that scientists have yet to work out. Diseases such as Cystic Fibrosis, colour blindness and Downs Syndrome are genetic diseases. Infectious Disease There are many ways that pathogens can be shared. An infectious communicable disease is a disease that is transmitted easily from person to person. The disease is said to be endemic if small numbers of cases are present in the population and an epidemic if large numbers of people are affected. An outbreak happens when the disease is suddenly out of control. Diseases Caused by Micro- Organisms Not all micro-organisms are harmful to humans. In fact, some are very helpful. Some micro-organisms serve as food sources, others help decompose wastes, some help protect us from disease and others aid digestion. Only a few micro-organisms cause disease. The micro- Not all micro-organisms are harmful to humans. In fact, some are very helpful. Some micro-organisms serve as food sources, others help decompose wastes, some help protect us from disease and others aid digestion. Only a few micro-organisms cause disease. The micro- organisms that cause disease are known as pathogens and include varieties of bacteria, viruses, protozoa and fungi. Bacteria One characteristic that is used to identify bacteria is their shape. They may be rod-shaped (bacilli), spiral (spirilla) or spherical (cocci). All bacteria consist of only one cell, but they can join together in pairs, chains or clusters. Bacteria can multiply very quickly under the right conditions. Bacteria Cont. If conditions are not favourable for growth, some types of bacteria can form thick- walled spores that allow them to withstand cold, heat and prolonged drying. They can remain inactive for days or even years. Antibiotics can kill many types of bacteria. Staphylococcus epidermidis bacteria Common Bacteria Shapes Viruses Viruses are so small that they can be seen only with an electron microscope. Viruses are not considered to be living things because they do not self-reproduce, feed, grow, produce waste or move. They do move from place to place, but only if they hitch a ride on something else, like other organisms, wind or water. Viruses are parasitic invaders made of DNA (or a similar material called RNA) in a protein coat. Viruses cont. If viruses come into contact with a suitable cell (called a host cell) they can attach to the cell and enter it. They hijack the cell and force it to make more virus particles. The cells make so many virus particles that they burst open, releasing the virus particles, which then invade other cells. Some viruses invade cells and remain dormant or inactive for long periods of time. An example is the herpes simplex virus, which is responsible for cold sores. Cold sores come and go, but the virus is always there, awaiting the right conditions for rapid reproduction and re-appearance. Others do not kill the cell they infect, but re-program it in a way that causes it to become cancerous. Viruses are hard to treat as they are not stopped by antibiotics. With most viral infections you have to wait until your body itself stops the invading virus. Foot and Mouth Virus The Problem with Viruses Because they are so small, viruses are difficult to isolate in the laboratory. They also multiply so rapidly that new strains are appearing all the time. As yet no chemicals can eradicate a viral infection. Protozoa Diseases caused by protozoa (sometimes called protists) are most often seen in tropical and subtropical areas. Like bacteria, protozoa are single- celled. Most protozoa are harmless to humans, but some parasitic types can cause serious illness. Protozoa sometimes form protective cysts around themselves if conditions are unfavourable, allowing them to survive between outbreaks. Giardia and Cryptosporidium are both examples of protozoa that contaminate water supplies. Another example is the common tropical disease, malaria. Malaria is caused by Plasmodium, which live in the red blood cells and cells of the liver. Falciparum malaria, the most dangerous type, is fatal in about 20% of untreated cases. Initial infection occurs through a female Anopheles mosquito bite. Fungi Very few fungi cause disease in humans and those that do commonly invade the hair, skin and nails. Fungi are opportunistic pathogens. They are not usually associated with infection, but they can cause infection if the conditions are ideal or if the persons immune system is not working properly. Fungi Cont People can have lowered immunity due to a number of causes and all are more susceptible to these fungal infections. Tinea (athletes foot), ringworm and thrush are all opportunistic fungal infections. Diseases Caused by Macroscopic Parasites Parasites that can be seen without a microscope are called microscopic parasites. Flukes The most common type of disease-causing macroscopic parasite is the flatworm. Parasitic flukes are flatworms, best known for causing disease in many animals, including humans. Intestinal flukes, blood flukes, lung flukes and liver flukes all affect humans, causing damage to the organs they inhabit, resulting in serious illness for the host. For example, blood flukes can damage blood vessels near major organs like the bladder and kidneys. Tapeworm Another type of flatworm is the tapeworm, which can sometimes live in human intestines. One type of tapeworm causes hydatid disease. If the tapeworms eggs are swallowed by humans, the tiny embryos will hatch from the eggs and move from the intestines into the bloodstream. Cysts develop wherever the embryos end up, most often in the liver. Here they are capable of killing the host human. Life Cycle of a Blood Fluke Bird Flu Bird flu, or more correctly avian influenza A virus, usually only infects birds. But sometimes these flu strains mutate into more dangerous forms. This happened in Hong Kong in 1997 when avian influenza (H5N1) infected both poultry and humans. This was the first time a bird flu had ever transmitted directly to humans. During this outbreak, 18 people were hospitalised and six of them died. To control the outbreak, authorities killed about 1.5 million chickens to remove the source of the disease. Further outbreaks occurred in 2003 and 2004. Similar pandemics have occurred in the past: 195758, Asian flu caused about deaths. 195758, Asian flu caused about deaths. 196869, Hong Kong flu caused approximately deaths. This virus still circulates today. 196869, Hong Kong flu caused approximately deaths. This virus still circulates today. Pathologists are concerned about the possibility that genes might swap between bird flu and human flu. This could happen if a person got infected with both diseases at the same time. The new bug would then have the potential to be as deadly as bird flu, and as easy to catch as human flu. It could then bring us the next pandemic. Transmission and Control of Infectious Diseases You can get infectious diseases by direct or indirect transmission. Direct transmission comes about by direct contact with the infected person or by contact with droplets of body fluid. Diseases transmitted by direct contact are called contagious diseases. Indirect transmission occurs through an intermediary agent like an insect, air or contaminated water. Carriers of disease are called vectors. An example of a vector is the mosquito that carries malaria from person to person. Natural control The first line of defence The human body has several mechanisms for coping with disease. The first defence is the outer layer of the skin, consisting of dead cells. Harmful pathogens on the skin can be shed with the dead cells. There are also a lot of good bacteria on your skin, which help fight the invaders. The second line of defence The second line of defence is in your blood, as white blood cells or leucocytes. They travel in the blood to the site of infection, converge on the pathogens, digest them and engulf their remains. Dead micro- organisms and dead white cells are left behind and form the discharge call pus. The third line of defence When invaded by a pathogen your body responds by making antibodies. These antibodies are produced in a process called acquired immunity. The antibodies float around in the blood and attach to a specific part of the pathogen, which is called an antigen. The antibody disables the pathogen, which is then easily consumed by white blood cells, thus destroying the threat. A particular antibody will act against the antigens on only one type of pathogen. The body can continue to produce antibodies long after the pathogen has been destroyed. The body will be immune to that particular pathogen as long as the antibodies are present. The process of acquired immunity Vaccinations The threat of many of the killer diseases of the past has been greatly reduced, and sometimes eliminated, by the development of vaccines. A person can be immunised against a certain disease by being injected (inoculated or vaccinated) with a vaccine. Most children in Australia are routinely vaccinated against diseases like polio, tetanus and measles, chicken pox and tuberculosis Two types of immunity can be produced by vaccines: Active immunity: the body is stimulated to make its own antibodies. This usually involves injecting a live but disabled version of the virus or bacteria. An example is the Sabin polio vaccine, which uses a live but non-contagious strain of the disease. Passive immunity: the body is injected with antibodies previously produced by another organism. This is good in emergency situations, where immunity is needed quickly. Unfortunately it does not last as long as active immunity. active immunity does not last forever. Production of antibodies can reduce with time and a booster shot (re-injection with the vaccine) may be needed. Antibiotics Antibiotics are drugs that are able to selectively kill off certain pathogens while leaving the patients own body cells intact. Although antibiotics can fight many bacterial infections, they are ineffective against viruses. Overuse and misuse of antibiotics have led to the development of antibiotic-resistant strains of bacteria. The more antibiotics are used, the more quickly resistant strains emerge. It takes up to 20 years to develop new drugs and soon doctors might be left without any drugs to fight the new strains. Non Infectious Diseases Genetic disorders are caused by abnormalities in one or more genes this means that the code contained on the chromosomes for building new cells is faulty. These genetic abnormalities may be caused by mutations mutagens such as radiation, drugs, chemicals and some viruses may be responsible. Once a new gene mutation has happened, the disorder it causes will be passed on to future generations. Eg Downs syndrome, Haemophilia Diseases Caused by Diet Malnutrition People in developing countries generally do not have the quantity or range of foods that you have, making them susceptible to malnutrition. Vitamin and mineral deficiencies can easily cause death. People in developing countries generally do not have the quantity or range of foods that you have, making them susceptible to malnutrition. Vitamin and mineral deficiencies can easily cause death. Eating disorders Anorexia nervosa results in severe weight loss, often enough to cause massive organ failure and death. Bulimia nervosa is a related disorder characterised by a bingeing and purging cycle. The imbalance of electrolytes (mineral salts) that results from this cycle may cause heart failure. Diabetes Diabetes mellitus is a disorder in which glucose, the energy source for your bodies, is not used correctly due to lack of a substance called insulin. Diabetes seems to have some sort of genetic component but there is no defined pattern of inheritance. There are two types of diabetes: juvenile onset (Type I) mature onset (Type II). Being overweight is a common factor in Type II cases. If the insulin deficiency is serious, regular monitoring and injections are needed throughout the patients life. Diseases of the Circulatory System In Australia, heart disease is the leading cause of death in males over 35 and females over 60. Many of these diseases are caused by poor diet, smoking and a lack of regular exercise. Thrombosis and Embolism Thrombosis is a disease that causes a large, solid mass (a thrombus) to form on the inside wall of a blood vessel. Sometimes these large masses can detach and end up blocking major arteries, causing death. The blockage of a blood vessel is called an embolism. The embolism can result from a thrombus, gas, fat, tumour cells or some type of foreign body. High Blood Pressure Hypertension is the name given to persistent high blood pressure. It can cause arteriosclerosis, or hardening of the arteries, and coronary heart disease. The worst type of arteriosclerosis is called atherosclerosis. It is characterised by fatty deposits within arteries. These deposits can eventually cause arteries to become blocked. Atherosclerosis can occur in any part of the body, not just the heart. It can be inherited, but is also strongly linked to environmental factors like smoking and diet. In WA, a four year study of 50 children aged from 10 to 16 and found that all the children had early signs of arteriosclerosis. Varicose Veins Irregularities in vein walls and weaknesses in the valves can stop blood flowing back to the heart normally. Varicose veins are the result and are usually seen in the legs, where blood must fight gravity to get back to the heart. Unsightly, bulging veins develop wherever blood is trapped. Heart Disease Coronary heart disease refers to anything that reduces blood flow to the heart and is usually caused by arteriosclerosis. It can cause milder attacks of chest pain, called angina, or a serious heart failure, called a heart attack. Cancer Cancer is one disease that is on the increase in Australia. Cancer occurs when the cell division that produces new cells occurs uncontrollably. Cell division is a carefully controlled process and even tiny changes within cells can be enough to disturb the process and produce cancer. A tumour is abnormal growth in the body. There are two types: A benign growth is one in which the cells are not rapidly dividing. A wart is an example of a benign tumour. A malignant growth is one in which uncontrollable growth is occurringthis is cancer. A biopsy is carried out to determine whether a tumour is malignant or benign. A small sample of tissue is taken, and is then analysed under a microscope. Cancer can occur anywhere in the body. The most common sites for cancers are the skin and prostate in men, and the breasts in women Factors that can lead to cancer are: environmental cigarette smoking (lung cancer), exposure to the sun (skin cancer), poor diet (bowel cancer), and exposure to certain chemicals, called carcinogens genetic predispositiona family history of breast or prostate cancer suggests that you have a higher risk of developing those cancers. If a malignant growth is found, it needs to be treated before metastasis occurs. Metastasis is when cancerous cells find their way into the circulatory or lymph systems and travel to other parts of the body. The disease becomes very difficult to treat once secondary cancer sites (called metastases) develop. Leukaemia is a type of cancer of the bone marrow and the tissues that produce blood cells. The first symptoms are usually fatigue, unexplained bruising and anaemia, caused by the lack of red blood cells. An abnormal number of white blood cells appear. Like most cancers, there is no known cure, but many treatment options are available. Common treatments for cancer are surgery, radiotherapy (using radiation to kill localised growths) and chemotherapy (using chemicals to poison cells). These treatments can have serious side effects. The best chance for surviving cancer is to detect it early while it is still small. Never ignore an unexplained lump anywhere on your body. Abuse of Psychoactive Drugs A drug is any substance that has the ability to alter a persons body chemistry. Psychoactive drugs are those that alter mood. Drug use is the controlled, beneficial use of a substance. Drug abuse is when a drug is used in a way that causes negative effects. People who use so-called recreational drugs like Ecstasy or marijuana are often unaware of the serious side effects that can occur. Often, users develop mental disorders that stay with them for life. Alcohol and Smoking Two of the most widely used and abused drugs in modern society are the legalised drugsalcohol and nicotine. Because they are legal, their use is much more widespread, open and accepted than illegal substances like heroin and amphetamines. Alcohol In Australia approximately 7% of all male deaths and 4% of all female deaths can be directly attributed to alcohol. Alcohol is technically a depressant drug. Although it doesnt necessarily make you depressed, it does depress your central nervous system, slowing down its responses. Alcohol has different effects depending on how much is consumed: With a little more alcohol, muscle coordination becomes difficult and speech slurred. Reactions are slower and the senses become dulled. Alcohol is a cause of around one-third of all road deaths. Hence the legal blood alcohol limit in New South Wales for all learner and provisional licence holders was reduced to zero in May Alcohol initially gives a sense of warmth and wellbeing, and a loss of inhibitions. If more alcohol is ingested, intoxication occurs. The person will be staggering, nauseated, possibly vomiting, and will have difficulty speaking. People are likely to fall into a coma if their blood alcohol content gets to 0.40%. Death through heart and respiratory failure can occur at around 0.60%. This rarely happens, however, since unconsciousness and vomiting have usually forced the person to stop drinking before then. Alcohol also stimulates urine production, dehydrating body cells. Part of the liver is put out of action while it works on processing alcohol. A by- product of all this processing are poisonous chemicals that are then released back into the blood. It is a combination of dehydration and these chemicals that give the symptoms of a hangover. Binge-drinking is particularly harmful since it gives no time for the body to process the alcohol. Chronic Alcohol Abuse This causes many ill-effects including: digestive problems alcohol destroys the lining of the stomach. digestive problems alcohol destroys the lining of the stomach. malnutrition and vitamin deficienciesdiet is often neglected. Although alcohol is rich in kilojoules, it has no nutrients. malnutrition and vitamin deficienciesdiet is often neglected. Although alcohol is rich in kilojoules, it has no nutrients. destruction of the liveralcohol can cause cirrhosis, a disease where cells are replaced by fibrous tissue destruction of the liveralcohol can cause cirrhosis, a disease where cells are replaced by fibrous tissue heart damagealcohol can harden artery walls heart damagealcohol can harden artery walls destruction of brain cells destruction of brain cells slow deterioration of the central nervous system. slow deterioration of the central nervous system. The abuse of alcohol can result in the disease called alcoholism, where drinking is compulsive and the person dependent on it. This dependence is most often psychological, but can develop into a physical dependence. Smoking More young women than men are currently smokers, one common reason being that it is an appetite suppressant. The nicotine in tobacco is addictive and once the habit is formed, it is not an easy one to give up. Withdrawal symptoms include intense craving, anxiety, sweating, depression, sleep problems and difficulty concentrating. Smokers are likely to have: more accidents than non-smokers, due to the slowing down of their reflex actions following a cigarette more accidents than non-smokers, due to the slowing down of their reflex actions following a cigarette constriction of blood vessels, which means that smokers brains dont work as well as non-smokers brains constriction of blood vessels, which means that smokers brains dont work as well as non-smokers brains a middle-age death rate twice that of non-smokers an increased risk of developing many diseases, not just lung cancer an increased risk of having low birth weight babies with health problems and reduced intelligence if the mother smokes during pregnancy bad breath stained teeth and fingers. Environmental Hazards Exposure to radiation, heavy metals such as lead, and chemicals such as asbestos are all environmental hazards that can cause diseases. Although these hazards are usually avoidable, some people are exposed to them without warning. Many environmental diseases have only been diagnosed relatively recently, since many take a long time to develop. Asbestos was once thought to be safe and many people innocently exposed themselves to it in the past. Traditional Medicine Traditional Aboriginal medicine is a complex system linked to the belief and culture of the people, their knowledge of the land and of its flora and fauna. Traditional medicine and health care are holistic, taking a whole-being approach. It recognises the social, physical and spiritual dimensions of both health and life. Sorcery remains a potent belief and the casting and removing of spells is still practised. Good Nutrition To survive, organisms must take in nutrients. A nutrient is any substance that is used by an organism either as a source of energy or to build living tissue. Fats, proteins and carbohydrates can all be used by the human body to make energy and so these are our main nutrients. A balanced diet should consist of a variety of foods including fresh fruit and vegetables, breads and cereals, dairy products, fish, lean meats and water.