3rd Class Science Our Body Sensory System

   Sensory System

We can see beautiful scene, hear pleasant sound, smell good things, taste delicious food, feel softness with the help of our sense organs eyes, ear, nose tongue and skin respectively. These sense organs constitute sensory system in our body.

These sense organs receive stimulus from the surroundings and send these messages to the brain through nerves for interpretation. Our brain respond to the stimuli with the help of these sense organs. Sense organs are called as receptor of information. For example, if we see snake coming towards us, eyes send this message to brain, brain interprets the situation and instruct the body to run. These process; occurs in a fraction of second.

Sense organs help in receiving stimuli from the surrounding and respond accordingly.  

         Problems in Sense Organs

A person affected of night blindness can't see in dark. A person affected of colour blindness can't differentiate between colours.

Visibility becomes less in cataract which generally occurs in old age.

Person can't hear at all (deaf) or can hear only loud sound if there is problem in ear.

          How to Keep Fit

Our sensory organs should be cleaned all the time. Eyes should be washed with clean water. Food rich in vitamin A is good for eyes. We should eat healthy and balanced diet. We should not play music at very loud sound.

     Match the following

P.                       P. Tasting

Q.                           Q. Smelling  

R.                   R. Seeing   

S.                       S. Feeling

T.                               T. Hearing  

(a) P-R, Q-Q, R-P, S-S, T-T                            

(b) P-Q, R-S, S-T, T-P, Q-R

(c) P-P, Q-Q, R-R, S-S, T-T                            

(d) P-T, Q-S, R-P, S-Q, T-R

(e) None of these  

Answer: (a)

Explanation

Eyes to see, nose to smell, tongue to taste, ear for hearing, and skin to feel. Therefore, option (a) is correct and rest of the options is incorrect.

     Which one of the following is not an eye disease?

(a) Cataract

(b) Sprain

(c) Myopia

(d) Hypermetropia

(e) Blindness

Answer: (b)

Explanation

Cataract, myopia, blindness, hypermetropia are eye diseases, whereas sprain is a muscular problem. Therefore, option (b) is correct and rest of the options is incorrect.

Human body also has a tail but it is a very short, stubby bone present at the base of the backbone.

There are more than 350 joints in the body.

Sneezes blow out of the nose at the speed of up to 95 miles per hour.

An average person breathes about 21,600 times every day

When we exercise, the heart beats faster i.e. more than 150 times each minute.

An adult’s stomach holds about 1 liter of food.

Enamel, the outside of tooth is the hardest substance in the body.

Bread, rice, potatoes, and pasta contains a lot of carbohydrates and milk, cheese, fish, meat and beans contain a lot of protein.

The size of heart is of a clenched fist.

When muscles work hard, they produce heat as well as movement.

A new born baby has more than 300 bones, but an adult has only about 206 bones because some of bones fuse together as a person grows.