Afaq NSS Science 6 - Unit 3 Structures and Functions of Sensory Organs

Afaq New Sun Series Science 6 - Unit 3 Structures and Functions of Sensory Organs

Afaq NSS Science 6 - Unit 3 Structures and Functions of Sensory Organs

Unit 3 Structures and Functions of Sensory Organs

Main Point to Remember:
  • There are five basic sense organs: skin, eye, ear, nose, and tongue
  • Skin is the sense of organ for touch. Our skin has receptors for pain, heat, cold, and touch.
  • Eye are the organs of sight and help us to see the world around us.
  • The ear is the sense organs that help us in hearing and maintain the balance of our body.
  • The nose helps us to smell different odors.
  • The sense of smell and taste are dependent on each other.
  • Our tongue is the sense organ for taste. We have four basic tastes: salty, sweet, sour, and bitter.
Important Definitions:
  • Skin: It is the largest sense organ of our body. It is the outermost layer that protects the inner parts of the body.
  • Pinna: It is the visible part of an ear, made of cartilage and covered with skin. It is a sensitive part which is effective in collecting sound waves.
  • Septum: A wall of cartilage that separates the two nostrils from each other.
  • Tongue: It is a muscular organ. It helps us to taste the food, swallow it, and feel its texture. It also helps us to talk.
  • Papillae: The tiny bumps on the tongue are called papillae.
  • Taste Buds: The taste receptors present between the two papillae are taste buds.

Excercise (Solved)

1. Answer the following questions briefly.
  1. Explain the functions of the skin.
    Ans: Skin has receptors of touch in it. It can detect various sensations such as press, pain, touch, heat, and cold.

  2. List down the basic parts of an eye.
    Ans: Following are the basic parts of an eye.
    a. Cornea:
    b. Pupil: 
    c. Iris: 
    d. Lens:
    e.Retina:

  3. Do the ears maintain body balance? How?
    Ans: Yes! Ears maintain body balance. Our inner ear contains bones of semicircular canals that are fluid-filled. When we move in any position the fluid in the canal also move, these canals have small hair as a receptor of balance that detects the change and generate nerve impulses and send message to the brain.

  4. How does the nose help us in smelling objects?
    Ans: In our nose, there is nasal cavity that contains olfactory hairs that have chemoreceptors. These chemoreceptors detect and identify various smells and send signals to the brain through nerve cells.

  5. Why cannot we taste things well when suffering from the flue?
    Ans: Because w
    hen we have a cold, due to the mucus in our nose we are not able to smell the odor and hence our brain is not able to tell us about the flavor of the dishes that we are having.
2. Answer the following question in details.
  1. What is an eye? Explain the internal structure of an eye.
    Ans:

  2. Discuss the function of the ear.
    Ans:

  3. What do you know about the sense organ for taste?
    Ans:
3. Choose the correct Option.
   

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