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Class 8, Science, Chapter-10, Lecture-3, Human Ear (Notes)

Structure of Human Ear: 

The human ear can be divided into three main parts, viz. external ear, middle ear and internal ear.

Outer Ear: 

The outer ear is outside the body and is also called pinna. It extends into the ear canal. 
Ear canal is filled with air.

Middle Ear: 

The middle ear is composed of 

  1. the ear drum or tympanum (it is an elastic membrane, circular in shape) and 
  2. the bone ossicles (the Hammer, the Anvil and the Stirrup).

Internal Ear: 

The internal ear is composed of 

  1. a cochlea and 
  2. three semi-circular canals.

Working of Human Ear:

  • The outer ear called pinna collects the sound waves.
  • The sound waves pass through the ear canal to a thin membrane called eardrum.
  • The eardrum vibrates. The vibrations are amplified by the three bones of the middle ear called hammer, anvil and stirrup. The middle ear then transmits the sound waves to the inner ear.
  • In the inner ear the sound waves are converted into electrical signals by the cochlea and sent to the brain through the auditory nerves.
  • The brain then interprets the signals as sound.