Class 8 MAHARASHTRA STATE TEXTBOOK BUREAU Solutions Science Chapter 2: Health and Diseases

Differences between infectious and non-infectious diseases:

a. Hepatitis (All other diseases are caused by the carrier mosquito)

b. AIDS (All other diseases are bacterial diseases)

Infectious diseases spread through contaminated air, water, food and vectors such as insects, animals and man.

Non-infectious diseases:

1. Asthma

2. Cataract

3. Kidney stones

4. Arthritis

5. Alzheimer

6. Cystic fibrosis

7. Parkinson's disease

Improper lifestyle, incorrect diet, lack of exercise, excessive mental stress and strain, imbalance in the secretion of hormones, are the main reasons for diabetes and heart diseases.

• Different diseases like cholera, enteritis, diarrhoea, dysentery, hepatitis and typhoid are caused by water-borne pathogens.
• Boiling of water kills all disease-causing pathogens present in it.
• Filtering of water prevents infections such as Naru caused due to nematode Dracunculus.
• Boiling and filtering of water helps to control the spread of epidemics caused due to infectious agents.

• Smoking and alcoholism are two dangerous habits that may lead to addiction.
• Alcoholism causes disorders of the liver. The addict suffers from malnourishment.
• Mental and psychological conditions of the addict become abnormal. Alcoholism has adverse effects on the personal as well as social well-being of the addict.
• Smoking is an invitation for cancer. Cigarettes and bidis contain a hazardous substance called nicotine which is not only toxic but also carcinogenic.
• It causes cancers of oral cavity, tongue, respiratory tract, and lungs among the smokers.
• Therefore, addictions like smoking and alcoholism should always be avoided.

• Regular balanced diet maintains good health.
• It increases the immunity of a person which helps fight off frequent infections.
• It establishes mental well-being of a person.
• Avoiding the consumption of high calorie junk food helps to prevent the occurrence of heart disease, diabetes and obesity.
• Exercise improves blood circulation.
• Several disorders caused due to faulty lifestyle can be prevented by having regular balanced diet and exercise.
• Hence, one must always consume a balanced diet and exercise regularly to maintain good health.

• According to ABO blood grouping system, there are four major blood groups - A, B, AB and O.
• During blood transfusion, the donor's and the recipient's blood should be well-matched with each other.
• If the blood groups are not matched properly, the transfused blood may get clumped inside the body of recipient.
• Also, the blood should be checked for the presence of infections. If the blood is not checked properly, viruses causing hepatitis B or AIDS may get transmitted to other healthy persons through infected blood.
• Thus, for prevention of transmission of diseases, blood should be checked before blood donation.

a. Master 'X' stays in an area which lacks cleanliness. Since he stays near a public toilet, he is more prone to infectious diseases such as typhoid, hepatitis, choler and enteritis. His father is a drunkard, so there will always be a dearth of money in his house. He may not be able to afford proper nutritious food. Thus, his diet must be deficient in vitamins and minerals. Moreover, his mother is ignorant about the importance of health and balanced diet. So, Master 'X' may suffer from malnourishment and reduced immunity. The overall financial conditions and the addition of the father must be adding stress in the house. This increases susceptibility to infections.

b. Master 'X' should be provided with a healthy and balanced diet containing fruits, vegetables and milk. His mother must be taught the importance of balanced diet. The surroundings must be kept clean and hygienic. Food should be covered so that houseflies do not contaminate the food. Germicidal floor cleaners and disinfectants should be used to keep off the houseflies and cockroaches. His father will be taken to de-addiction centres and persuaded to leave alcoholism.

c. Since father of Master 'X' is a drunkard, he can develop diseases of liver and kidney.

a. Preventive measures of dengue:

Care should be taken to drain out stagnant or accumulated water as there is a possibility of mosquito breeding.

Water storages such as man-made containers be either covered or decanted to prevent the breeding of Aedes mosquito.

Vaccination should be done to strengthen immunity to fight against the virus.

b. Preventive measures of cancer:

Stay away from carcinogenic substances such as tobacco, gutkha, cigarette and bidi as they contain nicotine which can cause cancers of oral cavity and respiratory system.

Avoid exposure to hazardous radiations.

Consume a balanced and healthy diet.

Exercise regularly and live a stress-free life.

c. Preventive measures of AIDS:

Blood should be checked for the presence of HIV during blood transfusion.

The used syringes and needles should not be used without sterilization.

Avoid unsafe sexual contact as it is the most important mode of HIV transmission.

Spread awareness about AIDS and HIV.

Importance of balanced diet:

• The diet which contains all the nutrients such as carbohydrates, protein, fats, vitamins and minerals in balanced proportion is called a balanced diet.
• Eating a balanced diet helps to prevent malnutrition.
• Immunity increases due to balanced diet containing sufficient amount of vitamins and minerals.
• Increased immunity prevents the occurrence of diseases.
• Improper lifestyle and incorrect diet can cause hypertension, diabetes and heart disease.
• Hence, to maintain good health and keep the body in equilibrium, it is important to consume a balanced diet.

Importance of physical exercise/yogasanas:

• Blood circulation of the body improves due to exercise and yoga.
• Body and joints remain flexible.
• Mental strain and stress is reduced.
• Insomnia, arthritis, indigestion, and some other disorders can be avoided.
• Exercise helps to stay away from addictions.
• Yoga maintains the levels of hormones and enzymes in equilibrium.
• Several respiratory and circulatory disorders can be prevented by keeping control over breathing through pranayama.

Following modern diagnostic methods are used to detect cancer:

• CT scan
• MRI scan
• Mammography
• Biopsy

Treatment of cancer is done by the following methods:

• Conventional methods
• Chemotherapy
• Radiation therapy
• Surgery
• Robotic and laparoscopic surgery