Samacheer Class 7 Science - Health and Hygiene

Practices to be followed for eye care.
Do not rub the eyes
Do not watch TV / Computer for a long time.
Use cold water for cleaning the eyes.
Eat lot of carrots which is rich in vitamin A needed for good vision.
Eat fruits like oranges, sweet lemon etc., regularly.

The regular hair wash and massage of the scalp will remove the dead skin cells, excess oil and dust.
Rinsing the hair well with clear water and using good toothed comb for hair dressing is highly essential for their maintenance.

Bruises refer to scratches. It is a surface damage that does not penetrate the lower tissues.
The affected area should be washed with cold running water and cleaned with an antiseptic cram on the wound.

Yes, In case of minor bums, the affected area should be washed with cold water.
In case of severe bums, deeper layers of tissues get destroyed and blisters appear.

Safety and First Aid
First aid is the immediate treatment given to the victim of trauma or sudden illness before medical help is made available. The first aid is
To save the life
To prevent further bleeding and determine the condition of the patient.
To relive the pain
To provide a medical care available at the earliest

S.no
1.
These diseases spread from one person to another person.
These diseases do not spread from one person to another person.
2.
They are spread through contaminated air, water, food or vectors, e.g Tuberculosis, Cholera.
They are caused due to wearing out of body parts or malnutrition etc., eg. Goiter, Night blindness.

Good oral hygiene implies sound teeth and healthy gums with healthy surrounding tissues.
When you brush two times a day, it will prevent the formation of tartar and plaque on, your teeth and gums.
When you floss, it will remove food particles, plaque, and bacteria which build up between your teeth. When you start flossing, your gums may bleed a little bit, but after few days that will be stopped.
It should be started only with proper medical guidance.
Eat a well balanced diet and avoid habits like chewing tobacco.

Communicable diseases spread from one person to another person through various modes as given below.
Mode of Transmission:
Food and water borne diseases – e.g Cholera, Typhoid
Air borne diseases – e.g Tuberculosis, cold
Insect other animals borne diseases – e.g Malaria, Rabies.
Contaminated food and water, air and Insects are the modes for transmission of communicable disease.

The condition of the hair reflects the nutritional status and general health of the body. Thin, sparse and lots of hair indicates poor nutritional status.
The following measures will help to maintain hair growth and avoid hair loss.
The regular hair wash and massage of the scalp will remove the dead skin cells, excess oil and dust.
Rinsing the hair well with clear water and using good toothed comb for hair dressing is highly essential for their maintenance.
Eating a balanced diet which provides all nutrients needed for the body will promote hair growth.
Applying oil to the skin and massaging the scalp will promote hair growth.
Use of chemicals (dyes, shampoos) must be used to avoid hair loss.

Communicable diseases are those that spread from one person to another. Diseases spread through contaminated air, water, food or vectors (insects and ohter animals) are palled as communicable diseases.
Tuberculosis:
Tuberculosis is caused by Mycobacterium tuberculae.
It spreads from one person to another person through air by spitting and prolonged contact with sharing materials of the patient.
Symptoms:
Fever, weight loss, Chronic cough, blood spitting and difficulty in breathing.
Prevention and treatment:
Getting BCG vaccination
Giving special attention to the patient,
Regular medication like DOT
Cholera:
Cholera is caused by Vibrio cholera.
It spreads through the consumption contaminated food or water.
Symptoms:
The symptoms of Cholera is vomiting, severe diarrhoea and cramps in legs.
Hepatitis:
Hepatitis is one of the most dangerous and fatal diseases caused by Hepatitis Virus A, B, C, D, E.
Its mode of transmission are contaminated water, sharing of needles and blood transfusion.
Symptoms:
Loss of appetite, (Anorexia), vomiting, eyes and urine in yellow color.
Prevention and treatment:
Drink boiled water.
Proper cleaning of hands.

The tissue damage caused by heat, chemical, electricity, sunlight or nuclear radiation is known as Bums. Mostly bums are caused by scalds, building fires, flammable liquid and gases. According to burning. There are three types of bums.
First-degree bums affect only the outer layer (called the epidermis) of the skin.
Second-degree bums damage the epidermis and the layer beneath it called ther dermis.
Third -degree bums involve damage or complete destruction of the skin to its full depth and damage to underlying tissues also. People who experience such bums often require skin grafting.
First Aid for Burning
In case of minor bums, the affected area should be washed with cold water and an antiseptic cream should be applied. In case of severe bums, where deeper layers of tissues get destroyed and blisters appear, use of water should be avoided. The burnt area should be covered with a clean non-sticking cloth or bandages. Larger bums need immediate medical attention.
It is very important to keep a fire extinguisher readily available.

Communicable Diseases are those that spread from one person to another. Diseases spread through contaminated air, water, food or vectors (insects and ohter animals) are called as Communicable diseases.
The communicable diseases are caused by disease causing microbes such as Bacteria, viruses etc.
These microbes are found in contaminated food, water, air etc.
Some of them like the malarial parasite complete their life cycle in the body of a mosquito.
Thus air food and water, sweat act as modes of transmitting these microbes from an infected person to a healthy person.
E.g. The cycle given below shows how food and water borne diseases are transmitted.S.no
Mode of Transmission
Examples
1
Contaminated food and water
Cholera, Typhoid
2
Contaminated air
Tuberculosis
3
Insect / Animal borne diseases
Malaria, Rabies

Many people are tired and do not have the energy to perform day to day activities. They tired and tend to sleep in the classroom or work place. Though sleep can be due to various reasons, the common reason for this condition is Anaemia.
People who are Anaemic have less number of Red blood cells in their blood.
The Red blood cells have haemoglobin which caries oxygen to all the cells of the body.
People who are Anaemic will have less slow oxygen supply to all the cells of the body.
Energy production in the cells is less and they feel tired and sleepy always. This is due to in the diet. Prevention : Eat food rich in Iron.