Getting to know Our Body

Our body has various parts just like a machine (Figure 1.1). These parts are called organs. Organs work together to make our body work

Whenever we look into a mirror we see many of our organs (Figure 1.2) i.e. eyes, ears, nose, etc. These are called external organs. The organs present inside our body are called internal organs

Major Body Parts and their Functions

Eyes

The eyes make us see the world around us. We have a beautiful world around us which is full of colours such as green trees, blue sky, etc. Eyes are the only organs of our body which can see this beauty and make our lives

Ears

At the end of the school time when the bell rings we become happy and start packing our bags for going home. Have you ever thought which part of your body makes you hear this sound? It is the ears which receive the sounds from all around us and make us hear (Figure 1.4).

Teeth

Teeth are very important part of our body. We chew our food with the help of teeth (Figure 1.5).

Count the number of teeth in your mouth. How many are they? We have two sets of teeth in our life time, one is milk teeth and the other is permanent teeth (Figure 1.6).

Milk Teeth

It is the first set of teeth which starts appearing at the age of 6 months. At the age of 3 years we usually have 20 teeth.

Permanent Teeth

Milk teeth start falling from 5 to 6 years of age. They are replaced by permanent teeth which are 32 in number

Getting to know Our Body

Bones

Look at the Figure 1.7. It shows the bones which are present in our body. Bones make up the structure of our bodies. We call this structure the skeleton. An adult skeleton is made up of 206 bones. The skeleton provides support to the body. Bones give shape to the body. The skeleton protects soft parts of our body. For example, heart is protected by ribs. What protects our brain?

Joints

Figure 1.8: Leg bones The point where two bones meet is called a joint. Joints help in movement. Some joints are fixed and do not move. For example, the joints in our skull. Some joints move a little, like the joints in our spine. Some joints move a lot, like our elbows and knees (Figure 1.9)

Getting to know Our Body

Muscles

Muscles perform many functions in the body. Muscles help us in walking, running, lifting things, writing and many other actions (Figure 1.10).

Movement of our Body by Muscles

Muscles can contract or relax. A bone is attached to the muscles for movement. Muscles can move a bone when they contract or relax. Muscles contract when they get message from the brain. For example, if you want to pick up your book, the brain will send a message to the muscles. On getting the message, the muscle contracts and pulls up the bone attached (Figure 1.11). After doing this the muscle will relax, which means that it will return to its normal size. In this way, you pick up your book or other things

Brain

Brain is the control centre of our body (Figure 1.12). The brain commands our muscles when to move. It makes us laugh and cry. It allows us to learn new things. It keeps on working even when we are asleep.

The brain receives different information from organs such as eyes, ears and nose. The brain reads each message and decides how our body should respond

Getting to know Our Body

Heart

Sometimes we get hurt and get a cut, blood flows out and we need a bandage to stop the bleeding. The blood in our body is continuously circulating. It is a need of our body. The flow of blood keeps us alive. Heart is the organ which pumps the blood so that it circulates throughout our body (Figure 1.13).

Figure 1.13: Heart

Stomach

Have you ever thought where the food you eat goes in the body? It is well chewed by the teeth and is pushed into the stomach (Figure 1.14). The stomach churns up the food. It breaks up the food into a sort of soup. Some of it is absorbed for body functions and the rest goes out as a waste.

Figure 1.14: Stomach

Lungs

We have two lungs in the right and left side of our chest. The lung on left is a little smaller than the lung on the right because it has to make room for our heart to fit in our chest. These are the organs which help in breathing (Figure 1.15). Breathing means taking air in the lungs and sending it out. Lungs take oxygen from the air and send it to the whole body.

Figure 1.15: Lungs

Getting to know Our Body

Skin

It is an important organ of the body which performs many functions such as it covers the body altogether (Figure 1.16). It stops germs and dirt from getting into the body

Figure 1.16: Skin of hand

Healthy body

Eating healthy food and doing regular exercise make our body healthy. These are the foods which you love to eat every day (Figure 1.17).

But all these foods are not healthy foods. food Healthy foods are the ones which contain all those things which our body needs. This food helps in our growth and makes our body strong. Vegetables, rice, flour, pulses, fruits, meat and meat products, milk and milk products are healthy foods (Figure 1.18).

Excess of everything is not good for health.

Foods which are not good for our health are called unhealthy foods, Example of unhealthy foods are chocolates, sweets, cold drinks etc. (Figure 1.19).

Eating too much of them can make our stomach upset and can harm our teeth.

We should walk and play daily. It makes us strong and healthy (Figure 1.20). Without this, bones and muscles become weak, and are easily damaged.

Getting to know Our Body

Malaria and Dengue Fever

Malaria and dengue are the diseases which are spread by mosquitoes. Malaria is caused by micro-organisms called Plasmodium. Plasmodium are transferred to human blood by the biting of Anopheles mosquito (Figure 1.21)

Figure 1.21 Biting action of Anopheles mosquito

Dengue Fever and its Prevention

You might have heard about viruses. Viruses are tiny living things that can only be seen with the help of a powerful microscope. Dengue fever is caused by a special type of virus. It is spread by Aedes mosquitoes which develop in the environment of standing clean water

Aedes mosquito, which spreads dengue fever, has black and white stripes on its body. This mosquito usually bites at dawn and dusk. Dengue virus is transferred to human body by the biting of Aedes mosquito. Biting action of Aedes mosquito is shown in Figure 1.22

Figure 1.22 Biting action of Aedes mosquito

The presence of dengue virus in the body of a person  can be known by the symptoms of the disease and the blood test.

Symptoms of Dengue Fever

Severe headache and vomiting.

• High fever and pain in the back and joints.

• Rash with red and black spots on body.

• Pain behind the eyes.

 • Usually bleeding from nose and gums.

Saftey Precautions

• Apply mosquito repellent lotion on your exposed body parts when you are going out.

• Sleep under mosquito net (Figure 1.23).

• Wear dress that covers maximum parts of your body (Figure 1.24).

• Keep doors and windows screened and closed especially in the morning and in the evening (Figure 1.25).