Individual health WHO definition of health A state

Individual health

WHO definition of health A state of complete physical, mental and social well-being, not merely the absence of disease and infirmity e. g. a person may not feel well although he is not actually sick. Health depends on how well your body is functioning, how well you feel about yourself and how well you fit with the society.

A balanced diet - why needed? • A balanced diet is a diet that contains the right proportion and quantities of different types of food substances for our body needs • We need energy for our daily activities and maintenance of our body temperature. We need to obtain sufficient energy-rich food substances, i. e. carbohydrates, proteins and lipids. • For body growth and repair (of worn out tissues), we also need sufficient amount of proteins and other nutrients such as fats, calcium and iron

• Our diet should also include various vitamins, minerals, dietary fibre and water to keep the body in healthy conditions • If a body does not get a balanced diet, it may result in malnutrition, overweight, deficiency diseases or constipation The food pyramid:

Improper Dietary habits 1. Eating at irregular hours and taking too much or too little food occasionally, esp. in people who are always busy in work, under strain, or eating in a hurry This may affect the normal functioning of the alimentary canal and lead to the development of peptic ulcer. 2. Food preference on a restricted variety of food, e. g. avoids taking meat or vegetables. This can result in malnutrition, e. g. Lack of meat iron-deficient anemia, becoming pale - looking and fatigues easily Lack of vegetables or fruits constipation

3. Snacks between meals May spoil a person’s appetite for normal meals if taken too much and may lead to an unbalanced diet. 4. Excessive calorie intake, e. g. too much sugary food May cause obesity or even tooth decay. A large amount of fatty food, a likely source of cholesterol, may lead to heart diseases. 5. Too much salty food May result in hypertension 6. Too much stimulants in food, e. g. caffeine in coffee Stimulates the nervous system and can cause person to be easily exhausted and eventually addicted. Prolonged drinking of coffee can result in anxiety, fast or irregular heart beat and habitual inability to sleep

Not too useful Dietary habits Taking tonics - to supplement the nutrient needs of the body, but balanced diet can already supply all nutrients needed. 1. Vitamin supplements Excessive amount of vitamins A and D may be toxic to the body. A high intake of vitamin D may cause the formation of renal stones. 2. ‘Health’ drinks They supposedly helps a person to recover from fatigue instantly because they contain glucose or particular minerals. Actually, a balanced diet can supply enough energy and nutrients to the body and there is no need to take in such ‘health’ drinks.

Value of suitable amount of exercise planned and repetitive physical activity) (i. e. 1. Reduces the chance of heart disease, cancer and other diseases 2. Helps to prevent ulcers and other physical and mental disorders by relieving tensions It also helps to achieve a feeling of well-being and for enjoyment. 3. Increases the strength of skeletal muscles, alertness of movement, coordination and reaction time. i) regular training through exercise raises the working capacity of the skeletal muscles by increasing the size and strength of the muscles.

ii) With regular training , there is improved coordination between skeletal muscles so that more skilful movement can be developed. iii) Exercise also improves muscle tone, allowing the body to respond more readily to sudden demands on physical responses 4. Improves body fitness and helps to maintain or lose body weight. 5. Regular exercise strengthens the respiratory muscles such as the intercostal, diaphragm and abdominal muscles, thereby increasing the vital capacity of the body.

6) Exercise also results in a stronger heart, so that number of heart beats can be reduced to bring about the same cardiac output. Accordingly, the stronger heart of an athlete can transport more blood to the muscles per unit time, thus providing more oxygen and glucose for the contracting muscles. Exercise also leads to an increase in number of red blood cells, thus increasing the oxygen-carrying capacity of the blood.

Precautions to be taken in exercise 1) Follow proper instruction when performing any sport or exercise. Proper technique helps to prevent injuries. 2) Do not perform any exercise when having a cold, fever or not feeling well. 3) Wear suitable clothing and shoes, and use appropriate instrument for the exercise. 4) Warm up the body for a few minutes before performing any sport. 5) Stop the sport and take a rest when the following happen: fatigue, pain, dizziness and vomiting.

6) Drink plain water to replace fluid loss due to sweating. 7) After exercise, take sufficient rest for the body to recover. 8) Do not take any steroids to improve the performance in sports. Many athletes use steroids to increase muscle mass and strength. Some of the dangerous effects of steroids include degeneration of the testes in the male, growth of dense hair on the face for the female, liver damage and clogged arteries.

Importance of rest to healthy living Continual activity, especially muscular activity, for a long time may lead to accumulation of toxic waste products and depletion of food reserve in the active tissues. Under such conditions, the body can no longer function normally and is said to be in a state of fatigue. To recover from fatigue, the body has to take a rest during which the exhausted cells remain relatively inactive. When the toxic wastes are completely removed and the food reserve is built up in the cells, they can resume normal activity again. We can rest by sitting down or sleeping. The quality of sleep determines how much sleep we need.

Stress A difficult situation that demands a person to adjust. Examples: Physiological - headache or sore throat Psychololgical - inner fear of net living up to standards or a conflict between a desire to please parents and peer groups. With external cause - examinations, dental visits, a noisy and crowded environment, death in the family, marriage, divorce, promotion or retirement.

Stress management Necessary because if person cannot cope with too much stress, he may develop abnormal behaviour and become mentally ill although mild stress can help us grow and develop to be more mature to prepare us for more extreme kinds of stress. How to deal with stress? 1) Talk to family members, friends or teachers to help clarify a problem, relieve emotions and find a solution. If they cannot help, seek professional advice or treatment from doctors, social workers or educational psychologists.

2) Try to analyse a problem calmly and realistically to see it in a better perspective. This may reduce stress caused by the problem and the problem may not be as serious as they may seem 3) Engage in sports or other physical activities to release emotions that upset a person. Taking part in community services can also help him develop self-confidence and take a more positive attitude towards his own problems. 4) Relax by developing healthy pastimes or participating in relaxation exercises such as yoga and tai-chi. This can help a person to cope with stress.

Undernutrition This occurs when there is insufficient intake of food. The body requires a certain amount of energy to work properly. This energy comes from the breakdown of food. The total amount of energy used varies according to age, sex, body size and occupation. If insufficient food is eaten to supply this energy, the body uses its stored fat and then body proteins. The effects of undernutrition also depends on the stage of life and the kinds of nutrients lacking. A child undernourished before birth may be born with one or more body defects. If serious undernutrition occurs during the first 2 years of life when brain growth is at is peak, mental retardation may result. Inadequate nutriton during childhood and adolescence may interfere with or even stop growth spurts as well as intellectual development.

Effects of a low protein diet This results in a disease called Kwashiorkor which occurs most commonly in young children who have stopped breastfeeding after the first six months and turn to a diet rich in starch. Symptoms: swelling of the belly, cracking of skin, and damage to the liver and pancreas.

Overnutrition When a person takes in more food than he needs, the excess food may be stored in the body as fat and this leads to overweight or obesity. Overweight people are usually not as healthy as slim people. They have a shorter life span and an increased risk of illness, including heart diseases, diabetes and high blood pressure.

Uses of food additives Food additives are chemical substances added to commercial food products for various purposes 1) as preservatives to prevent spoilage, i. e. to prevent the growth of microorganisms that cause food-borne illnesses and are hence hazardous to health, e. g. a) salt to preserve meat and fish b) sugar used in canned and dried fruits and in jams and jellies c) vinegar for preserving vegetables d) nitrite to preserve sausages 2) as antioxidants - to prevent oxidation when food is exposed to air, as oxidation causes changes in colour, appearance or flavour or even nutritional value of food, though they are not hazardous to health, e. g. Vitamins C and E.

3) as nutrient additives - to improve the nutritional value of foods, e. g. iodine is added to table salt, vitamin A and D are added to dairy products and vitamin C is added to fruit drinks 4) colourants to make food pretty, sometimes using dyes from natural sources (e. g. beta-carotene added to food products such as margarine, cheese and macaroni to give a yellow, red or orange colour). 5) as artificial flavours and flavour enhancers to improve taste or texture, e. g. used in ginger bread, sausage, ice-creams, ice-sticks, candies and jellies. Also, monosodium glutamate (MSG) is widely used in restaurants.

General effects of food additives Certain additives may cause allergies such as asthma, headaches, behaviour problems in children, damage to the kidneys and liver, and certain cancers. And, in general, children are more at risk than adults. Need for control of food additives Due to the possible harmful effects, food additives, before being released for public consumption, must be tested in animal studies to determine if they are safe enough. The minimal amount of them must also be used to provide the expected effect, such as protection against disease-causing microorganisms.

Major groups of Drugs - chemical substance that alters the way the body works, including not just dangerous drugs like opium 鴉片, heroin海洛英 or LSD迷幻藥 but also substances used daily by most people (e. g. tea and coffee) a) Narcotics 麻醉劑- opium and other drugs made from it, e. g. morphine 嗎啡, methadone & heroin b) Stimulants 興奮劑 e. g. caffeine & cocaine可卡因 c) Depressants: i) Sedatives鎮靜劑, e. g. barbiturates, the essential components of sleeping pills or ii) tranquillisers鎮定劑- drugs prescribed by doctors to anxious or psychotic people to relieve anxiety. d) Hallucinogens迷幻劑, e. g. LSD

Effects of Drugs a) Narcotics They act on centres of the cerebrum which perceive pain, producing drowsiness and sleepiness. Some of them are prescribed by doctors as analgesics (pain-killers) to relieve pain after operations or in severe illnesses. However, they can easily lead to dependence and are therefore known as ‘hard’ drugs. b) Stimulants They keep a person awake by stimulating body processes such as heartbeat and basal metabolic rate. They make the user ignore his body’s natural warnings to rest and as a result he becomes excessively fatigued. Constant use of stimulants may cause nervousness and confusion, poor judgment or even hallucinations or mental illness.

Students using stimulants to keep themselves awake at night to prepare for examinations can keep awake but will not be able to concentrate, leading to a state of confusion. c) Depressants Sedatives cause relaxation, drowsiness and sleepiness by depressing the activity of the cerebrum and cerebellum. As a result, the user’s judgement and coordination become poor, his reaction time is slow, and his vision and concentration are also affected. Abuse of the drugs lead to physical and psychological dependence and the use may easily take an accidental overdose. Tranquillisers act on regions of the cerebrum that are concerned with emotional reactions. People habitually taking tranquillisers appear to become less alert.

d) Hallucinogens These drugs affect the normal function of the synapses at the nerve endings and produce hallucinations. The user hears sounds and forms visions that exist only in imagination. Very small amounts of LSD can cause effects lasting for hours and hallucinations can occur again months after the user has stopped taking the drug. These drugs are dangerous because their effects are unpredictable. They may produce pleasant or horrifying illusions. Judgement may become so poor that the affected person may jump off a high building in the belief that he can fly.

Possible causes for people to start taking Drugs 1) Most young people probably start from curiosity, or because their friends are doing it and they want to be a member of a group of similar friends who smoke. 2) Others like taking risks, particularly if they know their parents or other adults would not approve 3) Some do so to try to relieve boredom 4) Some because they don't get along with their parents 5) Others because they are depressed, worried about school, work or family problems or as a 'cry for help' to attract attention. 6) Still others do so because they say it is stimulating, or it relieves tension.

This is because some drugs make you feel good. They can relieve your anxiety, elevate your mood, energize you, even change your perception of reality. They can also numb feelings of mental pain and enable you to avoid dealing with the problems in your life. Consequences of drug abuse 1) Drug abuse diminishes a person's ability to learn and act. 2) It alters mood and impairs judgment. 3) It lessens the person's ability to cope with life's problems and meet basic needs, often destroying self-esteem and increasing the potential for suicide.

4) Some drugs create dangerous hallucinations. For example, a person under the influence of drugs might imagine hearing threatening voices and react violently to these imagined voices. 5) Drug abusers tend to focus more on maintaining their drug habit than on maintaining relationships. As a result, they may suffer loss of friends and family, loss of jobs, loss of respect from non-drug users, loss of a legitimate way of life. 6) Increasingly isolated, drug abusers are forced to deal more and more with other people who take illegal drugs, thus entering a potentially violent subculture. 7) In order to assure a steady supply of drugs, the person may be drawn into crime. Many addicts become prostitutes, trading sex for drugs and spreading sexually transmitted diseases - gonorrhea, syphilis and the AIDS virus.

Risks of drug abuse to the foetus Depressants can retard development of the foetus and cause limb deformities. LSD can result in chromosomal anomalies and deformed babies whereas narcotics such as heroin and morphine can cause death of baby before it is born.

Excessive alcohol intake All alcoholic beverages contain alcohol formed by fermentation of sugar by yeast cells. Alcohol is toxic and causes various effects in the body. Alcohol does not need to be digested. After drinking, it is absorbed directly into blood through the walls of the stomach and small intestine within about 2 minutes and carried to all parts of the body. Its most important effect is on the brain, esp. those areas which control judgement, motor coordination and speed. Alcohol is absorbed fairly slowly in the stomach and more quickly in the small intestine. When a person drinks alcohol with an empty stomach, alcohol passes more quickly into the small intestine and therefore more quickly absorbed into blood. A stomach full of food, however, slows down alcohol absorption and the effects of alcohol on the person will be less severe.

Effects of alcohol Immediate 1) Alcohol slows down the passage of nerve impulses. A likely explanation is that the alcohol affects the synapse. A slowing down of nerve impulses explains the slow reaction times. 2) Even in moderate doses, alcohol interferes with motor skills, slowing down your control of your nerves, muscles, and senses. It results in poor muscular coordination, unsteady walking and slurred speech and it causes confusion and disorientation (losing one‘s perception of time, place or even one’s personal identity) as it distorts your perceptions of speed, depth and space. 3) Alcohol causes drowsiness. It may help you fall asleep faster but it can also cause you to awaken at intervals throughout the night. 4) Drinking too much also can result in stomach upset, causing nausea or tendency to vomit

Long-term 1) Excessive dribnking reduces appetite and so the person does not have a balanced diet. This leads to malnutrition and weakens the body’s resistance to diseases. 2) Too much alcohol causes the liver to swell and become yellow with fat. The liver may finally shrink and harden. 3) Excessive drinking can also lead to mental illness. The heavy drinker may experience terrifying hallucinations and his body may shake with convulsions. These effects are caused by a damaging action of alcohol on the nerve cells. 4) Alcohol drinking may shorten a person’s life expectancy. Poor health and judgement due to alcoholism makes a person more likely to be involved in an accident. Even small amounts of alcohol affect a driver’s vision and hearing and make his reflexes slow.

Risks of alcoholic consumption to the foetus during pregnancy Expectant mothers should not take any alcoholic drink because some damage is caused to the foetus. In severe cases foetal alcohol syndrome is produced. The babies have growth deficiencies, such as small heads and abnormal facial characteristics, and they often have subnormal intelligence.

Social consequences of alcoholism 1) More car accidents on the road result from heavy drinking than from any other cause. This is because alcohol slows down reflexes, interferes with concentration and distance judgement, and increases risk-taking, which may make you more likely to run yellow lights, for example. 2) alcohol can increase hostile or violent behaviour 3) crime - many murders and assaults are associated with excessive drinking 4) unhappy home life since alcoholics lose concern about their families and friends 5) poor work 6) absenteeism from work 7) illness 8) depression

Harmful chemical substances in tobacco smoke 1) Carbon monoxide - 400 times that of safe industrial exposure - reduces oxygen content in blood, causing heart to beat faster in order to increase the blood flow to various body parts. 2) Nicotine - slows down nerve impulse transmission at the synapse and gives the smoker a feeling of relaxation. It is responsible for the development of dependence on the smoking habit. 3) Tar - mixture of hundreds of chemical substances condensing to form dark, sticky substance on lung surface. They cause cancer & irritate the respiratory system, causing coughing and damage of the lung tissue. They also paralyze cilia which protect the respiratory passage from foreign particles such as dust and bacteria. 4) Other irritating substances

To show the presence of tar in cigarette smoke to suction pump cigarette U-tube OR white cotton wool squeeze the wash bottle a dozen of times to simulate the smoking action What is the function of the cotton wool ? Ans: The cotton wool in the U-tube serves to collect tar.

to suction pump cigarette U-tube OR white cotton wool What has happened to the colour of the cotton wool at the end of the experiment ? Ans: It changes from white to dark brown.

to suction pump cigarette U-tube OR white cotton wool Which substance in cigarette smoke causes the colour change ? Ans: Tar. The experiment illustrates how cigarette smoke may affect the lung surface by coating it with tar

Health risks associated with tobacco smoking 1) Cardiovascular diseases a) Coronary diseases Men who smoke are nearly 65% more likely to suffer from coronary disease and 2 to 3 times more likely to die unexpectedly from it than are men who do not smoke. Women smokers also have a higher incidence of heart disease than their non-smoking counterparts, and those who also take oral contraceptives increase their risks tenfold. In addition, these women risk developing blood clots that may cause strokes or impede movement.

Comparative death rates from coronary heart disease (men aged 50 -70) Relationship between smoking and coronary heart disease Non-smokers Stopped smoking more than 10 years Stopped smoking 1 - 10 years 206 160 100 Still smoking 220 175 154 109 Smokers of less than 20 cigarettes a day Smokers of more than 20 cigarettes a day Smokers show a greater incidence of coronary heart disease

b) Clogging of blood vessels Smoking accelerates the build-up of fatty materials within the arteries, including the arteries that supply the heart and brain. Moreover, chemicals in tobacco smoke affect blood platelets making them 'sticky'. They clump together and, together with red blood cells, form a blockage, or blood clot, which can slow or stop blood flow. i) clogged arteries in the heart can cause a heart attack ii) clogged arteries in the brain cause a stroke iii) clogged arteries in the legs can make movement of any kind, but especially exercise, painful. c) Reduced ability to carry oxygen due to carbon monoxide in tobacco smoke combining with haemoglobin in red blood cells d) Increase in heart pressure due to the acceleration of heart beat by nicotine, which also constricts blood vessels

Number of deaths 2) Lung cancer Over 80% of lung cancer can be attributed to smoking. The risk of lung cancer is clearly related to the amount of exposure to cigarette smoke - the length of time the person has smoked and the number of cigarettes smoked. The rate of death from lung cancers has increased greatly since 1915 while the death rate from other cancers has been dropping, suggesting a relationship between lung cancer and smoking. cancers other than lung cancer Year Number of deaths from lung cancer and other causes

2 or more packs a day 30 times the risk 1 12 - 2 packs a day 20 times the risk 1 pack a day O pack a day 10 times the risk never smoked Relationship between number of cigarettes smoked and lung cancer People who smoke are more likely to develop lung cancer than those who don’t smoke The more a person smokes the greater is his chance of getting lung cancer

Annual death rate/ 1, 000 men Death rate from lung cancer among men who gave up smoking cigarettes Years after giving up smoking The longer people have stopped smoking the smaller is the death rate from lung cancer

3) Other respiratory diseases a) Chronic bronchitis - repeated inflammation of the air passages between the trachea and the lungs. This is because chemicals in tobacco smoke kill cilia lining the air passage so that dirt and germs trapped by the mucus cannot be swept away from the bronchial tubes. b) Emphysema - a disease in which the lungs lose their normal elasticity and the walls of the tiny air sacs that absorb oxygen into the body are destroyed by chemicals in tobacco smoke so that they become thin & weak and are even broken down completely to leave large empty spaces in the lungs. As a result, the lung's surface area for the uptake of oxygen is reduced. The emphysema sufferer is short of breath after exercise.

Percentage of men aged 55 -64 who develop coughs or bronchial illnesses Effect of smoking on the chance of developing bronchitis Non-smokers Smokers: No. of cigarettes a day 1 - 14 15 or more Ex-smokers 50 40 30 20 10 men with persistent cough and phlegm men who have also had a recent bronchial illness Smokers show a greater incidence of bronchitis

4) Other cancers, e. g. cancers of the mouth, larynx, oesophagus, bladder, kidney, pancreas and organs connecting the mouth and pancreas. 5) Gastrointestinal disorders, e. g. gastric ulcer and duodenal ulcer. Passive smoking - breathing in of other people’s smoke The non-smoker suffers many of the harmful effects of smoking by breathing in contaminated air. These include nose and eye irritation, coughing, headache and an increased rate of heart and respiratory illnesses. Hence government implements many anti-smoking actions: 1) prohibit smoking in public areas such as concert halls, MTR/KCR trains and platforms, government offices, etc. 2) Requiring that cigarette packets and advertisements carry warning that smoking is hazardous to health 3) Heavy taxation on tobacco to discourage smoking

Risks of smoking to the foetus 1) Women who smoke have more abortions (foetus dies), stillbirths (baby born dead) and premature births (baby born early) than non-smoking mothers. Stillbirths and deaths in the first week of life occur 30% more often to mothers who smoke regularly after four months of pregnancy. 2) The babies born to mothers who smoke are smaller in size and are about 200 g lighter than those born to nonsmoking women. Although the placenta is enlarged to increase the oxygen supply to the foetus, nevertheless the foetus receives less oxygen if the mother smokes. 3) Nicotine may cross the placental barriers to harm the foetus. Fits and convulsions may be caused in young infants by nicotine. Nursing mothers also pass on nicotine in their milk to the young infants.

Situations leading to the development of a smoking habit 1) Some smoke in times of emotional stress or tension 2) Many smokers' social activities revolve around other smokers. 3) Users of all kinds of tobacco are often psychologically or physically dependent on it. They may be victims of psychological and social forces that combine to portray this habit as sophisticated, fashionable, and sexy. For decades, films portrayed beautiful but smoky nightclubs and glamorous stars smoking side by side. Once the habit is started, your mind may develop a dependency on the nicotine tobacco contains. Psychological dependency develops because nicotine can provide a sense of pleasure. This pleasure reinforces a smoker's desire to keep on smoking.

Mental health - definition Mental health is a state characterized by psychological wellbeing and self-acceptance. The term mental health usually implies the capacity to love and relate to others, the ability to work productively, and the willingness to behave in a way that brings personal satisfaction without encroaching upon the rights of others. In a clinical sense, mental health is the absence of mental illness. A mentally healthy person is someone 1) who is comfortable with himself Self-confident; able to stand failures; and is not enslaved by emotions of anxiety, anger, depression or fear. 2) who relates well to other people: Responsible, loving and trusting 3) who is able to adapt to society: Capable of working, solving problems in life, accepting changes and coping with stressful situations

Possible causes of mental disorders The exact cause of mental illness is still unknown, but rarely is it sparked off by any one single factor. The interplay of biological, physical and environmental factors is believed to be the main cause. In other words, a person may be born with a tendency to mental illness but the illness may not develop if other biological and environmental conditions are favourable. a) Biological factors, e. g. genetic make-up, physical constitution and temperament. b) Physical factors, e. g. head injury, infection of the brain, drugs and alcohol. c) Environmental factors, e. g. defective early development, maladjustment and stress or crisis. With the high stresses in the modern way of living, they are becoming more and more common.

Mental disorders Arise when a person cannot cope with stress and develops abnormal behaviour, i. e. becomes mentally ill. It ranges from mild reactions to stress to serious psychotic conditions. Some examples 1) Neurosis - mild form of mental disorder, usually showing exaggerated and excessive emotional reactions of anxiety and depression. They repeatedly check the same thing or wash hands. They may develop phobia towards particular things or situations. 2) Psychosis (精神分列症)- more serious form of mental illness which can lead to complete mental breakdown or insanity. A psychotic person may believe that everyone dislikes him and may even try to kill him. 3) Personality disorders - some distorted personalities developed during childhood, probably caused by lack of love, care or guidance. 4) Depression - feeling depressed in moments of frustration or disappointment. The feeling disappears quite rapidly normally but there is risk of suicide in severe cases.

Ways to prevent mental disorders Public health authorities customarily distinguish among three forms of prevention. 1) Primary prevention - attempts to prevent the occurrence of mental disorder, as well as to promote positive mental health. 2) Secondary prevention - the early detection and treatment of a disorder 3) Tertiary prevention - rehabilitative efforts that are directed at preventing complications. Two avenues of approach to the prevention of mental illness in adults are: 1) Reduce the stressful effects of such crises as unemployment, retirement, bereavement, and marital disruption; 2) Create environments in which people can achieve their full potential.

However, more emphasis should be placed on helping children through the following steps: 1) good care during pregnancy and childbirth, so that early treatment can be instituted as needed; 2) early detection and correction of problems of physical, emotional, and intellectual development; 3) developmental day-care programs focusing on emotional and intellectual development; and 4) support services for families, directed at preventing unnecessary and inappropriate foster care or other out-of-home placements for children.

Treatment for mental disorders 1) Drug treatment, e. g. using tranquillisers, sleeping tablets and anti-depressants. However the effect is only temporary. 2) Psychotherapy, which aims to help the patient and his family understand the cause of his problem, correct his abnormal behaviour and promote normal relationship with other people. During therapy, the patient is helped, e. g. to discover his hidden emotional conflicts, such as hatred, fear or frustrations developed in childhood or other stages.

Importance of social relationship in healthy living 1) Family - a good relation helps us to develop love and care, understanding, acceptance, tolerance and compromise with other people. 2) Work - a good relationship with colleagues, maintained by courtesy, sincerity and mutual understanding, is essential for a happy working environment, which can be a source of joy and achievement. 3) Leisure - Pastimes and creative hobbies can help to relieve tension and enables one to relax. Sports is good to the physical body and participation in community services can give us a sense of achievement and develop self-confidence. 4) Friends - We need friends for sharing joy and sorrow, and for support and help during difficult hours.

Diseases - Cause & Effect

Diseases (failure of body to work properly) Organisms causing them - pathogens, e. g. Bacteria, viruses, fungi, protozoa and some parasitic worms, e. g. liver fluke, tapeworm and Ascaris. tapeworm Ascaris They are said to be infectious if the pathogens are spread from person to person by various means, e. g. air, water, animals

How pathogens cause disease 1) Some pathogens release poisonous chemicals called toxins. Most toxins are proteins and are by-products of the parasites‘ metabolism. They produce disease symptoms in the host like high temperature, headache, and vomiting. 2) Others invade and damage cells. For instance, many bacteria attack mucous membranes, as in the respiratory and intestinal tracts. 3) Both processes may also occur at the same time.

Infectious diseases Causative agents: 1) bacteria spherical - Three common shapes: spherical, rod-shaped and spiral e. g. Escherichia coli. found in human large intestine Disease caused, eg. cholera (霍亂), pneumonia (肺炎), tetanus (破傷風) or tuberculosis (肺結核) rod-shaped spiral

2) viruses They are even smaller than bacteria and can be seen only under the electron microscope. A virus basically consists of a protein coat enclosing a strand of genetic material, which is made up of either DNA or RNA. Electron micrograph of a Disease caused, eg. bacterial virus (bacteriophage) colds (傷風), influenza (流行性感冒), �����pr oat rubella (German measles) (德國麻疹) �����D hepatitis B (乙型肝炎) or AIDS(愛滋病) bacteriophage

3) fungi They lack chlorophyll and cannot make their own food by photosynthesis. They are saprophytes or parasites. The body is made up of numerous filaments called hyphae which form a network called mycelium. They reproduce by spores. Disease caused, eg. Athlete’s foot (香港腳), ringworm (癬)

4) protozoa They are single-celled animals. Those which cause diseases are parasitic. Disease caused, eg. malaria (虐疾), vaginitis - inflammation and irritation of the vagina. amoebic dysentery (亞 米 巴 痢 疾 ), in which ulcer develops in intestinal epithelium and bleeds red blood cells attacked by protozoa causing malaria

5) Parasitic worms They invade a host, attach themselves externally and internally (to tissues and organs), and rob the host of nutrients, weakening the host and even causing diseases in them. Tissues which they infect include skin, muscle, lungs, intestine, lymphatic system or even the brain. a) Those which infect the digestive tract can cause abdominal pain, weakness, diarrhea, loss of appetite, weight loss, vomiting, anemia and malnutrition with deficiencies of vitamins, minerals (iron), fats, and protein. b) Those infecting the skin cause eruptions, fluid-filled sacs or even intense facial swelling. c) Those infecting the lungs can cause coughing (even of blood) and difficulty in breathing.

Life cycle of Chinese liver fluke ��fertilized eggs are passed down the bile duct into the intestine ��the larvae hatch into the adult form at the liver and produce a large number of eggs ��larvae move into the bile duct and the liver ��eggs pass out of the human body in faeces into water ��fish eaten raw or undercooked ��larvae leave snails and swim in water and burrow t skin of fresh water fish (usu. a carp) and develop ��eggs are eaten by snails in ponds or streams. Eggs then hatch into larvae

Means to prevent & control the spread of Chinese liver fluke 1) Cook freshwater fish thoroughly before eating 2) This kills all larval flukes in the fish. 2) Sanitary disposal of human faeces to avoid contamination of fish ponds with human faeces 3) Keeping ponds free of snails (e. g. by letting ducks feed on them) so that the life cycle of liver flukes cannot be completed.

Experiment to show the presence of microorganisms in air, water and food 1) Label 4 sterilized petri dishes containing nutrient agar A to D. 2) Open the lid of each agar plate slightly and carry out one of the following treatments. Close the lid immediately after each treatment. A Leave lid off for about 30 minutes and then replace the lid B Add about 1 cm 3 of water collected from an aquarium to the nutrient agar. Swirl the dish gently to spread the water

C D Add 1 cm 3 of fresh milk (or bread, meat or fruit) to the nutrient agar Untreated (control) 3) Seal the plates with adhesive tape and incubate them at 25°C for at least 48 hours. Stack the plates upside down. 4) Examine each agar plate carefully without opening it. Record the number of bacterial colonies formed in each agar plate. Q. Why should the agar plates be stacked upside-down during incubation? This is to avoid condensed water falling onto the agar.

Result Yellow or white spots appear on the agar surface, indicating the presence of bacteria. Each spot is a colony made up of millions of bacteria which are formed by repeated division of a single bacterium. Spots appear in dish A to C but not in D, indicating that bacteria are present in air, water and food.

Disease transmission

How infectious diseases are transmitted 1) By air and droplets Coughing, sneezing, talking or even normal breathing may discharge small water droplets into air. If these droplets contain pathogenic microorganisms and they are breathed in by another person, infection may occur. Diseases spread in this way include common cold, influenza, measles, chicken pox, pneumonia and tuberculosis. Infection in this way can be reduced when a place is well ventilated because then, water droplets evaporate more easily and most microorganisms will die. However, in crowded places such as buses and cinemas, air is humid and droplets evaporate slowly and remain suspended in air for a longer period. Covering the nose and mouth with a handkerchief can also give protection against infection.

2) Through contaminated water Water is a very common medium for dispersing the eggs of parasitic worms and pathogenic microorganisms that cause infections of the digestive tract, e. g. amoebic dysentery and cholera. When these organisms reproduce in the gut, their eggs or spores are carried out with the faeces. If the faeces is not disposed properly, the eggs or spores in the faeces may be washed by rain into streams or reservoirs and contaminate drinking water. Prevention: a) Dispose sewage in a sanitary way b) Bury faeces as far away as possible from streams and reservoirs.

3) Through contaminated food Food can be contaminated by: a) Washing food in contaminated water b) Leaving food uncovered in air, leading to visits by flies c) Handled by people with unwashed hands after going to the toilet Examples of diseases so caused: cholera and diseases caused by parasitic worms. Prevention: a) Cover food well and keep in refrigerator b) Wash and cook food thoroughly c) Wash our hands before meal or after using the toilet

4) Through vectors Vectors are animals (esp. insects) serving as agents in transmitting disease-causing organisms to man while they do not suffer any harmful effects, e. g. a) Mosquitoes - transmit malaria When a mosquito sucks blood from a person suffering from malaria, the parasites are taken into the mosquito’s body at the same time. Inside the mosquito, the parasites multiply rapidly and migrate to the salivary gland. When the insect bites another person, its saliva containing the malaria parasites is introduced into the person and the person therefore becomes infected.

compound eye protective tube bent back stylets piercing skin of host’s skin Sucking tube withdrawing blood from capillary A mosquito biting through the skin b) Dogs - transmits through their saliva a virus that causes rabies.

c) Houseflies - transmit many intestinal diseases When the flies visit faeces, pathogens such as the bacteria causing cholera or dysentery may be carried on their mouth-parts, legs or body hairs. These flies will contaminate human food, cups or utensils on which they land on. d) Cockroaches - transmit pathogens from dirty places to human food in similar way. e) Rats & mice - contaminate food with pathogens carried on their fur and feet.

5) Through contact Examples : a) Sexually transmitted diseases, e. g. gonorrhoea (淋病), and syphilis (梅毒) The bacteria causing the diseases are spread during intercourse or by contact with genital organs. They are very susceptible to drying and die quickly outside the body. b) Fungal diseases such as athlete’s foot A person may be infected if his skin makes contact with skin fragments bearing the fungus that have been rubbed on to a towel or a floor surface from an infected person. Prevention: 1) Protect the skin with suitable clothing and shoes 2) Avoid direct contact with people having skin diseases 3) Clean skin regularly to prevent accumulation of dirt & bacteria

Personal hygiene

Common measures of personal hygiene to keep the body clean and healthy to reduce the chance of bacteria or other pathogens making contact with or getting entry into our bodies. Hygiene of the hands Wash our hands after using the toilet or before eating, using soap or other detergents that remove fat from our skin which tends to stick microorganisms to the skin This is necessary because our hands constantly handle things such as furniture, door handles, books, coins and pets which carry microorganisms that stick to the skin of our hands. When our fingers touch food or wounds in the skin, these micro-organisms are transmitted into our body and can cause disease.

Hygiene of the feet Wash feet with soap and water and dry thoroughly after washing. Do not walk barefooted. Rationale The areas between the toes are often warm and moist. Such conditions favour the growth of fungi. Drying discourage their growth. Wearing shoes gives protection against infection by pathogens which may penetrate through the skin of the feet. Hygiene of the skin Wash skin frequently with soap or disinfectant (which inhibit growth of microorganisms) because sweat, oil and dirt may accumulate on the skin and promote the growth of pathogens that can result in pimples, for instance.

Hygiene of the eyes Avoid rubbing our eyes or using towels of another person for cleaning our eyes Rationale Scratching the eyes may cause damage to the conjunctiva and cornea which may lead to infection. Pathogens may also be transmitted through towels used by a person with infected eyes. Hygiene of the ears Take extreme care when trying to remove the wax accumulating in the tube of the outer ear, using sterile cotton wool or by washing, seeking help of qualified medical personnel if necessary. Rationale Hard object can damage the delicate eardrum, leading to infection or even deafness.

Disease treatment

Disease treatment The different methods: 1) Chemotherapy - the treatment of disease using chemical substances, natural or synthetic, to kill microorganisms or prevent their reproduction. Commonest chemical used: antibiotic - chemical substances produced by a variety of fungi and bacteria that suppress the growth of bacteria, e. g. penicillin and tetracycline. The effects of such antibiotics can be shown by: a) Inoculating a sterile nutrient agar plate with bacteria by spreading 2 cm 3 of a bacteria culture on the agar surfaces. b) Placing paper discs soaked with different antibiotics and water onto the agar surface.

c) Then seal the agar plate with adhesive tape. d) Incubate the agar plate at 25°C for at least 48 hours e) Observe the growth of bacteria on the agar surface. Paper disc soaked with antibiotic A B C D nutrient agar A B C D Paper disc soaked with penicillin streptomycin tetracycline water A milky surface on the agar shows growth of bacteria while a clear region indicates absence of bacteria. The inhibitory effects of different antibiotics on the growth of the bacteria used can be compared by measuring the size of clear region around each antibiotic disc after incubation.

Paper disc soaked with antibiotic Clear region (no bacterial growth) milky surface (with bacterial growth) You can develop resistance to antibiotics if you fail to take the full prescribed dosage (e. g. every 4 hours or every 6 hours around the clock for a certain number of days). Such a failure (e. g. stop taking the antibiotic after symptoms have disappeared) gives bacteria time to produce enzymes to destroy the antibiotic or to develop mutant forms of the organism to replace the vulnerable organisms. In any case, the result is that, in the future, the antibiotic in question will not be able to control a similar infection in your system.

2) Surgery - surgical operation on a patient to correct some disease conditions. It may involve removing an infected part of the body, a cancerous tissue, repairing a defective heart, setting a broken bone or attempting to correct a damaged brain. It takes place in an operation theatre under sterilized conditions to prevent infection of the patient. 3) Radiotherapy - the treatment of disease with ionizing radiation such as X-ray. The radiation can be used to kill certain cells such as cancer cells. 4) Physiotherapy - the use of physical methods to relieve pain or to improve the physical state of the patient. It may involve the application of low electric current, heat or massage. etc. to the affected body part or performing adequate exercise. It is normally used to treat diseases that affect the nervous & muscular systems and the joints. 5) Psychology - for the treatment of mental illnesses.

Occupational and industrial health hazards A number of occupations in industry involve the handling of substances that are toxic to the body. Special precautions must be taken to prevent their intake. A few examples include: 1) Lead and mercury - which have harmful effect on the nervous system 2) Asbestos - which can cause lung cancer

First Aid

First aid Objectives 1) 2) 3) 4) To save the patient‘s life To prevent the injury or illness from becoming worse To reduce suffering and shock To get qualified medical help as soon as possible Some treatments a) Artificial respiration Used to maintain breathing in a person when he has stopped his breathing movements (such as due to drowning, choking, suffocation, head injuries, gas poisoning and electric shock). A person will die if he stops breathing for 4 -6 minutes, and the brain will suffer permanent damage if it does not receive oxygen supply for 2 minutes. It is therefore essential to carry out artificial respiration on the victim with no delay.

Mouth to mouth resuscitation The rescuer blows air into the victim’s lungs through the mouth. The exhaled air of the rescuer contains oxygen (16 -17%) and carbon dioxide (4 -5%). The oxygen helps to maintain aerobic respiration in the victim’s body and the carbon dioxide stimulates the respiratory centre of the victim to start working again. When the rescuer blows air into the victim’s mouth, the victim’s nose must be held closed. It is also important to tilt the head well back so that the tongue does not block the air passage. If the air passage is blocked by the tongue, as shown in the diagram above, or by other material, air will not be able to reach the patient‘s lungs Tilting the patient‘s head back as far as it will go keeps the air passage open as shown in the diagram above.

1. Ensure that the air passage is clear. Remove anything that may block the mouth or throat. Loosen the clothing. 2. Tilt the head backward as far as possible. 4. Stop blowing. Watch for the victim‘s chest to fall 3. Take a deep breath. Pinch the victim‘s nostrils. Put your mouth over the victim’s mouth and blow slowly. The victim‘s chest should rise. 5. Repeat the blowing at about 12 breaths/minute until the victim starts breathing

b) Prevention of minor wounds Small cuts on the skin may lead to infection by microorganisms. A minor wound should be washed thoroughly in clean, cold water. If the wound is dirty, a mild antiseptic can be applied to the wound with sterile cotton wool. Bleeding normally stops quite quickly. Dry the wound and cover it with an adhesive plaster or bandage. c) Treatment of bleeding If the wound is deep, a lot of blood may be lost and this can be dangerous. It is important to get medical help quickly, e. g. by calling an ambulance. Before medial help is obtained, bleeding may be reduced by washing the wound in clean water and applying pressure to the wound with a piece of clean cloth.

If the above treatment does not stop bleeding, apply additional pressure to the major artery that supplies the wounded area. When an artery can be pressed against the bone to prevent bleeding beyond it, the site is known as a pressure point. If severe bleeding cannot be stopped by pressing on the wound, it may be possible to stop bleeding by applying pressure on a suitable pressure point. Press on the pressure point only when dressing the wound. Never apply pressure on the pressure point for more than 15 minutes, otherwise the tissues may suffer permanent damage due to lack of oxygen.

c) Treatment of shock (休克) In a state of shock, a person looks pale and keeps sweating. His breath is rapid and shallow, and his pulse rapid and weak. He feels cold, weak and dizzy and may even lose consciousness. These symptoms are caused by a reduced blood supply to vital organs of the body, esp. the brain. Treatment 1) Treat any injury or condition which has caused the shock, e. g. stop severe bleeding 2) Have the victim lie down in such a way that his head is slightly lower than the rest of his body. 3) Loosen his clothing 4) Cover the victim with a coat or a light blanket 5) If the victim is conscious, give him warm drinks such as tea but not alcoholic drinks. Do not give drinks to an unconscious person.

d) Treatment of joint injuries Sprains (扭傷) occur at joints when the ligaments connected with a joint are torn. Sprained joints are usually associated with swelling of the joint and severe pain. The victim may not be able to move. He may be treated as follows: 1) Apply a cold compress, e. g. a wet cloth, to the joint 2) Wrap the affected region with a bandage so as to immobilize the joint. 3) Consult a doctor for medical help and to check on the state of damage.