DISEASES
Think about the last time you were sick. How did you feel? Being sick is not fun. Sometimes you have to stay in bed. You may not want to eat. You may not be able to play with your friends. Very small living organisms are all around you right now. They are so small that you need a microscope to see them. These very small living organisms are called germs. Germs are in the air. Germs are on your desk. Germs are even inside your body.
Germs can cause diseases. A disease is a sickness. Different germs cause different kinds of diseases.
There are many kinds of germs. Bacteria are one-celled germs. Some bacteria may make you sick. A sore throat may be caused by a type of bacteria. Not all bacteria make you sick.
The cells of bacteria can have three shapes.
A virus is the smallest kind of germs. It grows inside the cells of other living things. A virus can make you sick. Some viruses cause colds, flu, and other diseases.
Germs Live in Your Body
Your body is a warm place, in which germs can live. Your body has food for them. It also has water for them. Germs need warmth, food, and water. Most of germs can grow where there is warmth, food, and water.
Your body kills most of the germs that grow inside it. Sometimes it cannot kill enough of germs. When too many germs begin to grow, you become sick. Your body may need help to fight the germs. Medicine kills some kinds of germs.
How You Are Protected
Suppose you are at a football game. You hear people yell "Defense!". They want their team to defend their goal. To defense means to protect or guard. The team without the ball tries to stop the other team from scoring. They protect their goal. Your body has ways of protecting itself from germs.
Your skin is one kind of defense. It can stop germs from entering your body. If the skin is cut or broken, germs can enter your body. Keeping cuts clean is one way to help your skin protect your body.
Some germs do enter your body. Certain cells in your blood kill these germs. These blood cells are another defense against diseases.
Another body defense is producing antibodies. An antibody is a chemical in blood that kills germs. Each antibody kills a certain kind of germs.
Antibodies are produced by your body in two ways. Each time you are sick because of a germ, the blood makes antibodies kill that kind of germ. Antibodies are also made after you are given a vaccine. A vaccine is made of dead or weak germs that cause your blood to produce antibodies. These antibodies kill any of those germs that may enter your body.
You can also help protect your body from diseases. Wash your hands with soap and water after you use a toilet. Do not get too close to people who are sick. Have your doctor give you checkups.
NUTRITION
Nutrition is the science that deals with food and how the body uses it. Food supplies the energy for every action we perform. It also provides substance that the body needs to build and repair its tissues imd to regulate its organs and systems.
A proper diet helps to prevent certain illnesses and aids in recovery I'mm other. Eating a balanced diet is the best way to ensure that the liody receives all the food substances it needs. The daily diet should Include a certain number of servings from each of five food groups:
vegetables;
fruit;
breads, cereals, rice and pasta;
milk, yogurt and cheese;
meat, poultry, fish, dried beans and peas, eggs and nuts.
Food provides certain chemical substances needed for good health. I he substances, called nutrients, perform one or more of three functions:
1. They provide materials for building, regaining or maintaining body tissues.
2. They help to regulate body processes.
3. They serve as fuel to provide energy.
I liere are six main groups of nutrients. Water is the most critical nutrient. One can live without other nutrients for several weeks, but «1 can go without water for only about one week. The body needs «Hit to carry out all its life processes. Adults should consume about! 2.5 litres of water a day. Carbohydrates include all sugars and •.inn lies. They serve as the main source of energy. The main sugar in It»id is sucrose, ordinary white or brown sugar. Fructose comes from (n*»‘.l fruits and many vegetables. Lactose is found in milk. Foods con- hilnliig starches include beans, breads, cereaJs, com, pasta (macaroni). hin nre a highly concentrated source of energy and they are composed "i mi alcohol called glycerol and substances called fatty acids. Proteins luiivide energy and serve as one of the main building materials of the Muscle, skin, cartilage and hair are made up largely of proteins. Every cell contains proteins called enzymes, which speed up chain* nl reactions. Minerals are needed for the growth and maintenance u| body structures. Calcium, magnesium, phosphorus are essential pail ti| the bones and teeth. There are trace elements which include chruml um. cooper, fluorine, iodine, iron and zinc. Iron is an important pail nl haemoglobin. Vitamins should be supplied daily in the diet.
