ICSE Selina Class 9 Biology Hygiene PDF

Downloaded from https:// www.studiestoday.com Unit-6 Health and Hygie...

Downloaded from https:// www.studiestoday.com Unit-6 Health and Hygiene HyGiENE — [A KEy 10 HEALTHY LiFE] 15.1 SIMPLE PERSONAL HYGIENE (iii) Teeth should be cleaned at least twice a Hygiene is defined as the science and practice day—before going to bed at night and after getting of maintaining good health. It requires caring of up in the morning. one’s own body (personal hygiene) and taking * Mouth should be washed after every meal. proper care of surroundings (social hygiene). The * Too much eating of sweets and chocolates spoils major aspects of personal hygiene are as follows : the teeth causing caries and gum infections. 1. Cleanliness 3. Rest and sleep (iv) Breathe by Nose. One must always breathe 2. Physical exercise 4. Healthy habits by the nose and never by the mouth. One should blow 1. Cleanliness. Personal cleanliness is most the nose into a handkerchief and should hold a essential. handkerchief in front of the mouth and nose while (i) Hands and skin must be cleaned regularly. sneezing. We are continually handling a variety of things— (v) Eyes must be cleaned and washed with clear furniture, books, coins, currency notes, seats and water two or three times everyday. Trachoma and supporting rods in buses, pets and other domestic conjunctivitis are two common diseases of the eye animals, tools and machinery in workshops, and so caused through dust and through contamination by on. All these objects may carry germs which may be hands and towels. For preventing eye infections : picked up by our fingers and transferred over other e One must never share towels with others, even parts of the body or into the mouth through food. in the same family. o The practice of washing Two dirty habits : o The Indian custom of applying “kajal” (soot) hands with soap after may sometimes lead to infections of the eyes using toilets is very through the shared applying sticks, so never important. share such sticks. e A daily bath regularly (vi) Ears should be kept clean. keeps the skin clean Turning book pages or ¢ The wax inside may be cleaned by soft moist and free of germs, the counting currency notes swab. body odours given out by saliva wetted finger tip. in perspiration are © One should never put any sharp pointed object removed and keeps the sweat pores open. into the ear, it may injure the eardrum. Particular attention must be paid to the cleansing 2. Physical exercise. Some physical exercise is and drying of the various clefts and folds of the necessary for all age groups, especially children, skin, for example, of arms, legs and toes. adolescents and young people. Long gentle walks are * Undergarments and handkerchiefs must be enough for the old. Physical exercise should be washed daily. systematic and regular. It improves blood circulation. (ii) Hair should be kept clean by frequent 3. Rest and sleep. All organs of the body including the brain (mind) need rest. In general, the washing and regular combing. This keeps it healthy and free of parasites (like head-lice). body obtains adequate rest by means of sleep. The € 138)- Downloaded from https:// www.studiestoday.com  Downloaded from https:// www.studiestoday.com amount of sleep required varies with age. The very young infants sleep for most of the day. For adults ?| ProGRESS cHECK 6-7 hours continuous undisturbed sleep is sufficient. 1. Fill in the blanks ' (i) Cleanliness, rest and sleep, and phyncalmxe are 4. Healthy habits. One should develop good a part of hygiene healthy habits such as going to bed at night at regular (ii) One must always breatheby they bt and neverby time, taking food at regular hours, etc. the , e In general, going to bed at late hours or (iii) Fresh air brings _ into the living rooms. immediately after taking dinner are not good (iv) One must never put a sharp pmmed object into the habits. it may rupture the ______. X * Bowels should be cleared everyday preferably (v) For adults 6-7 hours of continuous nndlsmrbed in the mornings. is sufficient e Tobacco should be avoided—it is injurious to (vi) mmuniclpnlbodwsmmenmlhemppb'ofdm health and may even lead to cancer. germ-free and an efficient disposal. e Taking stimulants and sedatives are unnecessary and spoil habits. 2. Llstmythreeadvanmgesgfadulybnh. 3 * Drinking alcoholic beverages is definitely (0) harmful to one’s own body as well as to society. (i) (iii) The living rooms should be well ventilated for fresh air and sunlight. Fresh air brings oxygen and Economic Importance of Housefly. The sunlight kills germs. housefly is a kind of natural scavenger cleaning 15.2 SOCIAL HYGIENE AND SANITATION and consuming the left-overs of the food, etc. But the dangers which the housefly poses to human life All public places such as schools, office are so serious, that it is often designated as Public ) buildings, bathrooms, lavatories, cinema halls, etc., Enemy No. 1. It spreads numerous diseases including should be kept clean. dysentery, cholera, typhoid, etc. The eating places such as hotels, restaurants, The manner in which the housefly spreads roadside dhabas and their surroundings must be kept diseases : clean and free of flies. All eatables must be covered. All utensils, cups, glass-tumblers and spoons, etc., 1. Hairy body and legs pick up filth : The body must be thoroughly washed preferably with soap and and specially the legs are hairy or spiny. They hot water. easily pick up filth containing germs from dirty places. Such a fly contaminates our food by All public drains and garbage must be covered sitting on it A resting housefly always keeps on and some disinfectants such as bleaching powder, rubbing its legs against themselves and over the lime, etc., must be frequently sprinkled. body, thus dropping particles of filth. The civic bodies (municipalities, etc.) must 2. Pouring out saliva : Food is also contaminated ensure the supply of clean germ-free drinking water with germs when the housefly moistens the and an efficient sewage disposal. foodstuffs by pouring out its saliva on it, or Control of Disease-carriers (Vectors). when it vomits (regurgitates) food which it has Vector is any agent that acts as an intermediate swallowed from dirty places. carrier of the pathogen. Many insects and other 3. Excreta : It deposits its excreta while it feeds, animals spread diseases. Steps should be taken to and thus contaminates human food. control or to eradicate them. Control of houseflies 4. Direct transmission of germs : Sometimes it mosquitoes and cockroaches should be given directly conveys the infection. For example, maximum priority. These three are considered the germs of trachoma ( a disease of the eyes) are worst public enemies. € 139)- Downloaded from https:// www.studiestoday.com  Downloaded from https:// www.studiestoday.com directly transferred when a fly which once settled dwelling places. Spraying on ponds and marshy on the infected eyes of a patient, next time sits places kills the life-history stages. on the eyes of a healthy person. Elimination of breeding places. Breeding places Control of the housefly. There are several should be destroyed. Small ponds and puddles methods to control houseflies. should be filled up. 1. Elimination of breeding places. All refuse from 3 Spraying on stagnant water. Kerosene or some houses, and all animal and human excreta should other greasy oil should be poured over the water be removed at regular and frequent intervals and to make a thin film on the surface. The oil kills disposed off in such a way that the flies cannot the larvae and pupae when they come to breathe breed in it. If the refuse be covered by a layer of on the surface. earth, enough heat is produced in it by 4. Biological control. Certain fishes such as decomposition, which is sufficient to kill the Gambusia should be introduced in the ponds. maggots, if any. They selectively devour mosquito larvae. Spraying. Houses and breeding places should be sprayed with DDT and other insecticides. Avoidance. Food should be kept well protected and covered. Flies should not be allowed to sit on the body. Sleeping babies should be protected by baby umbrellas. 15.3 MOSQUITOES AND DISEASES 1. Anopheles mosquito spreads malaria in man, monkeys and birds, etc. The malaria germ is a protozoan Plasmodium. Culex mosquito spreads elephantiasis (filariasis), 154 COCKROACHES caused by a nematode worm Wuchereria. These are very common household insects A third mosquito, Aedes spreads yellow fever breeding mostly in the connecting manholes and and dengue, both caused by their respective sewers. They extend their activities to kitchens, viruses. cupboards and wardrobes. They eat and spoil food, The germs of these diseases are spread when the paper and clothes. They are also suspected to be mosquitoes bite to suck blood. With this blood, the carriers of certain viral diseases, including possibly mosquitoes receive germs of the particular disease, a cancer-causing virus. Spraying DDT and other which grow and multiply within their body. When insecticides in their breeding places is an effective such infected mosquitoes bite a healthy person, these method of control. germs are introduced into his body through the saliva. 15.5 RATS Before sucking blood the mosquito first injects its Rats are serious domestic pests. Besides eating saliva into the skin, which contains a substance that grain and other foods they also spread germs of prevents clotting of blood to facilitate suction. certain diseases. Rat-flea is a parasite which lives CONTROL OF MOSQUITOES on rat’s skin. It may carry germs of plague. Plague Several steps are recommended to destroy had spread as a serious epidemic during the earlier mosquitoes in different stages : part of twentieth century in many parts of the world 1. Spraying. Adult mosquitoes should be destroyed killing a number of people. Rats should be trapped and disposed off or be killed by suitable rat poisons by spraying DDT and other insecticides in (raticides). Q140) Downloaded from https:// www.studiestoday.com  Downloaded from https /l www.studiestoday.com 157 THE THREE COMMON WATER BORNE DISEASES In case the water supply agencies are not very cautious in purifying water, the residents of the area may suffer from three common diseases, cholera, typhoid and dysentery which may take the form of severe epidemics. 1. Cholera You have already read a little about cholera under “Diseases caused by Bacteria”. The main 15.6 CONTAMINATION OF WATER AND WATER- points are as follows : BORNE DISEASES o Infection of intestinal tract is by a bacillus Vibrio Contamination means unwanted entry of cholerae. disease germs into drinking water or edible o It appears as sudden onset with sickness and foods. severe diarrhoea and vomiting * No urination due to shortage of water in the body, Clean and germ-free drinking water is very urea accumulates in the blood, which is highly essential for personal and public health. poisonous and causes death. Contamination of potable (drinking) water can occur in several ways such as : Infection of cholera occurs through o Sewage if improperly disposed of, leaks into sub contaminated water and also by dust and flies that soil and may contaminate water supplies. sit on excreta and may transfer germs to exposed foods. Food handlers with dirty hands can also * People defecating or urinating near lakes, rivers transmit the germs. or ponds may contribute to contamination of water. 2. Dysentery e Animal wastes and washings from dairies, There are two forms of dysentery — bacillary poultries, efc. may also be drained into water and amoebic. bodies. (i) Bacillary dysentery. The causative agent is a Besides the above principal sources of bacterium (Shigella). It occurs frequently contamination, there can be a variety of industrial among children. The disease is marked by and agriculture wastes that may contain poisonous loose motions (diarrhoea), intestinal pain and chemicals and can be harmful to human health. For mild fever. Patients are treated with antibiotics. example : Prevention includes drinking safe (boiled) e Industrial wastes containing mercury cause water and avoiding flies from contaminating abnormalities in the nervous system. food. o Tannery wastes contain the pathogen anthrax (i) Amoebic dysentery. The causative agent is a bacilli and are the most serious water pollutants. protozoan Entamoeba histolytica. * Pesticides especially DDT are most serious water pollutants, pesticide concentration in humans PSEUDOPODIUM cause hormonal imbalance, leading to cancer. * Presence of fluorides in drinking water causes NUGLEUS tooth disorders, bone disorder and in higher BLOOD CELL concentration it causes neuro — muscular disorders and may be fatal to life. Fig. 18.4 Entamoeba histolytica {141) Downloaded from https:// www.studiestoday.com  Downloaded from https:// www.studiestoday.com o This organism enters our body through Symptoms : contaminated water and food. It establishes » Body ache in the lining of large intestine where it o Eyes yellowish, deep yellow urine (due to bile feeds by engulfing red blood cells of the pigments) patient’s intestine. This amoeba has no o Enlarged liver contractile vacuole and bears one large blunt pseudopodium. Prevention : o When fully mature it forms cysts which pass * Hepatitis vaccine out through faeces. The cysts remain active Proper hygiene for a long time. On reaching a new host through * Avoid taking fat rich substances contaminated water and food they split off to infect a new individual. PROGRESS CHECK 3. Hepatitis mw(;)lf the following statements are True (T) or There are three types of hepatitis. The name (i) Contamination means entry of germs by insect hepatitis refers to liver (hepatos = liver), meaning bite 2 T/F inflammation of liver. There are three types of (ii) Sewage is the commonest source of contaminationof hepatitis — Hepatitis A is the infectious hepatitis water in the cities T/F transmitted through contaminated water. The other (iii) Cholera is marked by acute diarrhoea and no two types (hepatitis B and hepatitis C) are passed urination TF through blood and other body fluids. (iv) Typhoid is caused by a type of worm T/F (v) Mosquitoes are the source of dysentery germs T/F POINTS TO REMEMBER > For keeping healthy we require three things : a balanced diet, proper personal hygiene, and good sanitation > Personal hygiene includes cleanliness of hands, skin, teeth, eyes, ears, etc. > Physical exercise improves blood circulation. > Healthy habits such as keeping to regular timings in one’s daily routine of taking food or going to bed, etc. keep one fit. All public places must be kept clean. Vv Housefly breeds in cowdung, horsedung, etc. and its life-history includes egg, larva (maggot), pupa and v imago (adult). Housefly spreads germs of several diseases including dysentery, typhoid, cholera, etc. Anopheles mosquito transmits malaria and Culex mosquito transmits filaria. Mosquitoes breed in water and all the stages in the life-history of Culex and Anopheles slightly differ in shapes or postures Cockroaches and rats are common household pests which spoil and damage our food and other articles. Contaminated water produces three very common diseases - cholera, dysentery, hepatitis. Hepatitis (actually hepatitis A) is a viral disease causing inflamation of liver and symptoms of eyes turning yellow, and passing deep yellow uring. {142)- Downloaded from https:// www.studiestoday.com  Downloaded from https:// www.studiestoday.com A. MULTIPLE CHOICE TYPE 2. Describe the different ways by which the housefly X No urination due to shortage of water in the body contaminates our food. is a typical symptom of 3. Suggest any two methods of controlling flies. (a) typhoid (b) malaria 4. List any three effective methods for controlling (c) dysentery (d) cholera mosquitoes. Which one of the following is an unhealthy habit? (a) Removing wax from inside the ears C. SHORT ANSWER TYPE (b) Keeping the mouth closed while breathing 1. Name the two common kinds of mosquitoes and (c) Sleeping for only 6-7 hours the diseases they transmit. (d) Sharing towels with others 2. How would you differentiate between Culex and The protozoan that causes malaria is : Anopheles mosquitoes pertaining to their : (a) Entamoeba histolytica (b) Euglena (@) eggs, (c) Paramecium (d) Plasmodium (ii) larvae and the chemical substance mainly responsible for tooth (iii) adults disorders is (a) calcium (b) chloride D. LONG ANSWER TYPE (c) flourides (d) iodides 1. Give suitable explanations for the following : Thyphoid is caused by (i) One should breathe by nose and never by (a) housefly (b) bacteria mouth. (c) virus (d) None of the above (ii) Hands must be washed before eating food. B. VERY SHORT ANSWER TYPE (iii) Eating places must be kept free of flies. 5 Match the stages of housefly in Column I with a 2. How are cockroaches and rats harmful to humans. characteristic in Column II. 3. Name the two types of dysentery and their Column 1 Column 11 causative germs and give one main precaution (a) Eggs (i) Sucking proboscis against them. (b) Adult (i) Barrel-shaped (c) Pupa (iii) White cylindrical (d) Larva (iv) Legless {143 Downloaded from https:// www.studiestoday.com