Mechanism of Hearing – Class 11 | Chapter – 21 | Biology Short Notes Series PDF

Mechanism of Hearing: How does ear convert sound waves into neural impulses, which are sensed and processed by the brain enabling us to recognise a sound ?

Mechanism of Hearing

  • The sound waves travel to the ear canal (external auditory canal in the figure). This is a tube-shaped opening in the ear.
  • At the end of the ear canal, the sound waves hit the eardrum (tympanic membrane). This is a thin membrane that vibrates like the head of a drum when sound waves hit it.
  • The vibrations pass from the eardrum to the hammer (malleus). This is the first of three tiny bones that pass vibrations through the ear.
  • The hammer passes the vibrations to the anvil (incus), the second tiny bone that passes vibrations through the ear.
  • The anvil passes the vibrations to the stirrup (stapes), the third tiny bone that passes vibrations through the ear.
  • From the stirrup, the vibrations pass to the oval window. This is another membrane like the eardrum.
  • The oval window passes the vibrations to the cochlea. The cochlea is filled with liquid that moves when the vibrations pass through, like the waves in water when you drop a pebble into a pond. Tiny hair cells line the cochlea and bend when the liquid moves. When the hair cells bend, they release neurotransmitters.
  • The neurotransmitters trigger nerve impulses that travel to the brain through the auditory nerve (cochlear nerve). The brain reads the sound and “tells” you what you are hearing.

Biology Quiz & Notes Physics Quiz & Notes Chemistry Quiz & Notes

Follow on Facebook

By Team Learning Mantras