3rd Class Science Our Body Notes - Our Body

Our Body

1. Our body is like a living machine which can see, hear, smell, taste, move, grow, breathe and reproduce.

2. Our body is made up of many different parts called organs. Each organ has its own role to play.

3. The organs which help us to feel or sense the things around us are called sense organs. We have five sense organs: eyes, ears, nose, tongue and skin. These organs help us to see, hear, smell, taste and feel.

4. Sense organs take messages from the outside world and send them to the brain through nerves. After receiving the messages from the sense organs, the brain passes orders to the different organs of the body. Then the body works according to the orders.

5. The eyes help us to see the objects. We can see near and distant objects and know the shape, size and colour of the objects. Eyes give us the sense of sight.

6. The ears help us hear all types of sounds. They give us the sense of hearing.

7. The nose helps us to smell different kinds of things. We can distinguish between sweet smell or a foul smell. Nose helps us in the sense of smell.

8. The tongue helps us to taste things and helps in the sense of taste. We can taste sweet, sour, salty and bitter flavours.

9. The skin gives us the sense of feeling. It gives us the feeling of cold, hot, pain, pressure, touch, etc. It also helps us to feel if a thing is smooth or rough.

10. Organs of our body do not work alone. A number of organs in our body are connected together to do a particular kind of work. Such kind of arrangement is called an organ system.

11. Skeleton system is made up of bones and forms framework of the body. It gives form, shape and support to our body we can stand, sit, walk and move because of our bones. There are 206 bones in our body.

12. Nervous system consists of brain and nerve. It receives messages from the sense organs and other parts of the body and sends orders for the action. It controls all our actions of seeing, hearing, speaking, learning, thinking, etc.

13. Muscular system is made up of muscles. Most of the muscles are fixed to the bones. Bones and muscles work together. This system helps us to move about and do different kinds of work.
14. Respiratory system helps us to take in air from outside. We breathe in air through our nose. The hair present in the nose stop dust and germs from the air. Thus, the fresh air from the nose enters the lungs. In the lungs the blood takes oxygen from the air. This oxygen is used to 'burn' the food to get energy. The air we breathe out has carbon dioxide and is impure.

15. The digestive system helps us in taking food and making it ready for use in the body. The food we eat is in the complex form. The body cannot use it till it is broken down into a simple form. The organs of the digestive system break down food into a simple form. The digestive juices in the stomach help to make it into a soluble form.

16. The excretory system removes waste materials from the body. The kidneys, lungs and skin help to remove out waste materials from the body in the form of urine, sweat and carbon dioxide.

17. The circulatory system is made up of heart, blood and blood vessels. It carries blood to all parts of the body. The blood supplies food, oxygen and other materials to different parts of the body and take back waste materials from them.

18. The reproductive system helps us to produce babies. This system helps life on this earth to continue.

19. Our heart is located in our chest. We have two lungs located inside chest, one on each side. We have two kidneys in our abdomen.