THE BODY SYSTEMS
Body system is a group of organs which works together to form a system. The work is carried on in a very systematic manner from one organ to another. A body system keeps functioning whether we are awake or a sleep.
Our body has several systems. These are:
• The skeletal system .The respiratory system
• The nervous system .The reproductive system
• The muscular system .The digestive system
• The circulatory system .The excretory system
The Skeletal System:
The skeletal system is a framework of 206 bones. It gives form, shape, size and support to our body. The bones help the body in movements. The skull protects delicate organs like the brain and eyes. The ribs protect the lungs and heart.
The Muscular system
The ends of most muscles are joined to the bones. Along with the bones, muscles help the body to move, work and do other activities. Muscles also give shape to our body. There are over 600 muscles in our body
The Respiratory System
The organs involved in this system are nose, Wind pipe and the lungs. We breathe in air through the nose. This air enters the lungsthrough the wind pipe.
The lungs take in oxygen and supply it to the whole body through the blood. The air breathed out contains more carbon dioxide and other impurities. The fine hair in the noise blocks the dust particles contained in the air. We must breathe through the nose and not through the mouth.
The Digestive system:
The organs involved in this system are the mouth, food pipe and stomach (the small and large intestines).
The process of digestion changes food into a simple form. The process of digestion begins with the chewing of the food. Saliva mixes with the food in the mouth. This makes the food soft and easy to swallow. The food enters the food pipe and then goes in to the stomach. The food stays in the stomach for a few hours. Here it changes in to a thick liquid.
The food is completely broken down into a simple form in the small intestine. The digested food is absorbed by the blood. The undigested food passed in to the large intestine and out of the body through the anus as waste.
The Circulatory System:
The heart, blood vessels and blood are involved in this system. The heart pumps blood through blood vessels to all the parts of the body. The blood supplies oxygen and nourishment. It also carries back all the waste material from the different parts of the body.
The Excretory system
The organs involved in this system are skin, lungs, kidneys and the large intestine.
The excretory organs of mankind help in removing the body wastes regularly.
- The skin throws out sweet.
- The lungs expel carbon dioxide and other impurities.
- The kidneys throw out urine.
- The large intestine throws out solid waste (faces) through the anus.
- This keeps the body clean and healthy.
The Nervous System
This system involves nerves, spinal cord and the brain.
The nervous system is connected to every part of the body. Messages are carried from and to every part of the body through the nerves. Our actions and reactions are all controlled by this system.
We will learn more about the reproductive system in the higher classes.
4.1.5. HAIR, TEETH AND THEIR CARE
Hair and teeth are important to the body. Can you guess the use of your hair and teeth?
5.1 HAIR
Everybody is born with hair on their head. Different hair styles make each of us look different. Hair also server another important purpose. It prevents loss of body heat through the head.Look at the hair of the children in your class. Hair is of different colors and textures. Some have light brown hair. Some have straight hair and some have straight hair and some have curly hair.If you look carefully you will find some children have shiny hair. Shiny hair is healthy hair. They take good care of their hair. You, too should take care of your hair.
Hair Care:
- Wash your hair regularly. If hair is not washed regularly
- Always comb your hair neatly.
- Always use your own comb.
- Clean your comb regularly.
- Apply oil on the scalp and hair regularly.
- Hair should be kept short or tied neatly to protect it from dust.
5.2 TEETH
Do you eat solid food? Do you chew this food in to very, very small pieces? What are the parts of your body that help you in this process?
Teeth are important part of our body. Teeth give shape and structure to the face. Teeth help us to bite and chew our food. Teeth help us to chew solid food materials such as vegetables, fruits and nuts. Teeth help in speech. We are able to form words and speak clearly.
The first set of teeth which appear in a baby are called milk teeth. By the age of two years, the child has twenty teeth. By the age of two years, the child has twenty teeth. At the age of six years, the milk teeth begin to fall. New teeth, which come in the place of old teeth are called permanent teeth. By the age of twenty-five years an adult has thirty-two teeth.
Different kinds of Teeth:
We have three kinds of teeth. They have different functions.
Incisors (Biting teeth)
The front teeth are thin, flat and sharp. We need them to bite in to the food.
Canines (Tearing teeth)
These teeth are pointed and used to tear off pieces of food.
Molars (Grinding teeth)
These teeth are at the back. They are broad, flat and strong. They are used to chew food.
What can happen to our teeth if we do not take good care of them?
1. Food particles will remain between the teeth
2. Bacteria will thrive on theses food particles.
3. This will cause foul smell of the mouth.
4. The teeth will decay. Gums will get infected.
5. This may result in a toothache.
How can we take good care of teeth?
1. We should brush our teeth every morning.
2. We should also clean the tongue and massage the gums after brushing.
3. Eat plenty of fibrous fruits and raw vegetables to clean and strengthen teeth.
4. Wash and gargle every time you eat something.
5. Brush your teeth at night before bed time
more questions-
I. Choose the right answer.
a. ________________animals have strong arms and legs to climb trees.
aerial aquatic arboreal
b. ___________________ is needed by our body for making blood.
Calcium Iron Zinc
c. Mosquitoes are ____________________ that suck the blood of other animals.
carnivores parasites herbivores
d. _____________________ are needed to repair damaged parts of our body.
proteins vitamins minerals
II. Name the following.
a. Reduced activity of some animals during winter. ___________________________
b. Animals that give birth to young ones.______________________
c. A mineral that is needed to form healthy bones and teeth. ____________________
III. State True or False. If False, write the correct statement.
a. Elephants can change the colour of their skin to match their surroundings.
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b. Exercise is essential for staying healthy.
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c. Vitamins and minerals help our body to fight diseases.
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d. Removing all water from food to stop germs from growing is called canning.
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IV. Answer the following questions.
1. What are amphibians? Give an example.
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2. How does a hedgehog protect itself from its enemies?
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3. List the functions of albumen in an egg.
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4. What is a balanced diet?
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Please click on below link to download CBSE Class 4 Science Worksheet Set B
