3rd Class Science Our Body Organs of Our Body

     Organs of Our Body

Our body is made up of cells. Cells are the smallest unit of life. Cells, which are similar in structure and function, group together and perform a common function. These group of cells are called tissues. Accordingly, many similar tissues combine together and perform a common function, called organ. Eyes, nose, heart, brain, lungs, skin etc. are different organs of the body.

               Eye                                               Brain                                     Nose                                    Heart                           Lungs  

These organs perform different functions. For example, we see with our eyes, smell with our nose, heart pumps blood to all the parts of the body whereas lungs help in taking in oxygen and giving out of carbon dioxide.

Our body is a living thing and hence it performs functions like breathing, feeding, growth, reproduction, excretion and respond to changes in the environment etc.

These processes are not so simple and it can't be performed by a single organ rather many organs are involved in each process. These groups of organs are called organ system. Human body is a complex organism comprising of many organ system. Food, which we take, has to pass through a long process till are digested and absorbed by the blood. Passage of food through the body is depicted by the flow chart given below.

Look at the following chart of the flow of food in our body:

         Digestive Diseases

Uneasiness and indigestion causes due to overeating or not chewing food properly.

Diarrhea and vomiting occurs when germs or bacteria enter the body through infected food.

           How to Prevent Digestive Disease

We should eat healthy food, i.e. lots of green leafy vegetables and fruits. Food should not be eaten fast, rather it should be chewed properly. We should also drink plenty of water for proper digestion of food.

     Which one of the following is an organ of human body?

(a) Heart

(b) Eye

(c) Ear

(d) All of these

(e) None of these

Answer: (d)

Explanation

Heart, eye, ear all are the organs of human body. Therefore, option (d) is correct and rest of the options is incorrect.

     Which one of the following is the first step of food's digestion?

(a) Chewing the food

(b) Mixing of food with saliva in the mouth

(c) Swallowing

(d) Breaking of food into stomach

(e) Both (a) and (b)

Answer: (e)

Explanation

First food is chewed and mixed with saliva in the mouth, passed through the food pipe into the stomach, where food is digested and broken down into smaller pieces. From there the food passes into small intestine where further digestion takes place. Therefore, option (e) is correct and rest of the options is incorrect.