Sense Organs

Sense Organs of Human Body for Class 5 Science

From this concept, the students will learn about the sense organs of human body.

After reading the concept, students will be able to:

• Identify the parts of the human eye.
• Understand the structure of human ear.
• Know about the function of nose.
• Understand the roles of human tongue taste buds.
• Know about the skin sense organ.
• Get an idea about the defects of vision and their correction and hearing impairment.

Each concept is explained to class 5 students using descriptions, illustrations, and concept maps. After you go through a concept, assess your learning by solving the two printable worksheets given at the end of the page.

Download the worksheets and check your answers with the worksheet solutions for the concept of the Sense Organs of Human Body provided in PDF format.

• The organs in our body that help us see, hear, taste, smell and feel are called sense organs. They are a vital part of the nervous system.

The five sense organs in our body are the eyes, ears, nose, tongue and skin.The sensory function of the nervous system depends on the sense organs, which collect information by the sensory receptors present in them.Sensory receptors perceive the external environment signals, which are then passed on to the brain and interpreted.

 

Eyes:

• The organs of sight are the eyes.
• Eyes are sensitive to light.
• The colour of the eye varies from person to person. The part of the eye which imparts its colour is the iris. It is filled with melanin.
• The eyes can receive the light rays and make an image on the retina.
• Light falling on the retina activates the light receptors present there, which in turn, generate electrical impulses. These impulses are then sent to the brain via the optic nerve.
• The region of sight in the brain interprets those signals which make us realise the things we see.
• The scientific study of sight is called optics.
• There are several disorders related to the eyes. The sight disorders are cured by using the lens.
• Age-related disorder like cataract is cured by surgery.

 

 

Ears:

• The sense organs which can perceive sound are called ears.
• The ear can be categorised into—outer/external ear, middle ear and inner ear.
• The outer ear is responsible for receiving the sound waves, which are sent to the middle ear afterwards.
• The middle ear comprises three bones, malleus, incus and stapes. After receiving the sound waves, these bones turn them into electrical impulses that are then sent to the brain via the inner ear.
• The inability to hear is called deafness.
• Deafness can be due to birth defects or physical injuries after birth.
• Deafness is cured by using a hearing aid.

Nose:

The nose helps us to perceive the sense of smell.Sense of smell is regulated by the olfactory centre in our brain.The nose performs the following functions—

1. It is a vital part of the respiratory system. The nostrils in the nose are used for inhaling air.
2. The hair present inside the nose help in filtering the air by blocking the entry of dust, pollens etc.
3. The nose also plays a role in the sense of taste, and this is why we tend to lose our sense of taste when we catch a cold.

 

• The inability to detect smell is called Anosmia.

Tongue:

The organ which helps us to perceive different tastes is called the tongue.The region of the brain that controls the tongue’s functioning is called the gustatory region.The tongue comprises taste buds on its outer surface which help detect different tastes.The tongue can identify sweet, sour and bitter tastes. There are different regions meant for different tastes on the tongue.The inability to taste is called Ageusia.

Skin:

• The largest organ that covers our body is the skin.
• Skin receptors allow us to perceive temperature, pain, texture and pressure.
• There are neural receptors present on the skin that generate nerve impulses. These impulses are then transferred to the brain.
• The inability to feel anything is called tactile anaesthesia.

 New Words:

Did You Know?

Crickets hear by using an organ named the tympanum, which is located on their front legs.The smallest bone of the human body is located in the middle ear.We blink our eyes at least 15 times in a minute.

 

Whiskers in animals are used for tactile sensation.The body of the grasshopper is covered with hair which helps in the detection of movement of air.Good smells make us feel happy.Bear can smell its food from 18 miles away.