- Books Name
- Science Made Easy Science Book
- Science Made Easy
- CBSE Class 9
Structure of Human Ear
→ The ear consists of three parts: outer ear, middle ear and inner ear.
→ The ears are the sense organs which help us in hearing sound.
→ The outer ear is called pinna. It collects the sound from surroundings.
→ This sound passes through the auditory canal.
→ At the end of auditory canal, is a thin elastic membrane called ear drum or tympanic memb
→ The middle ear contains of three bones: hammer, anvil and stirrup linked with one another. F
end of hammer touches ear drum and that of stirrup linked with membrane of oval window of
→ The lower part of middle ear has a narrow ‘Eustachian tube’.
→ The inner ear has a coiled tube called cochlea, which is connected with oval window. Cochle
filled with a liquid containing nerve cells.
→ Other side of cochlea is connected to auditory nerve which goes to brain.
Working of Human ear
Pinna → Ear canal → Ear drum → Hammer → Anvil → Stirrup → Oval window → Cochlea → Audi
nerve → Brain
→ When compression of sound wave strikes the ear drum, the pressure on the outside of ear d
increases and pushes the ear drum inwards.
→ While during rarefaction ear drum moves outwards. Thus, ear drum starts vibrating back an
→ These vibrations are increased by three bones and middle ear transmits these amplified pre
variations received from sound waves to inner ear.
→ In the inner ear the pressure variations are turned into electric signals by the cochlea.
→ These electric signals are sent to the brain via auditory nerve and the brain interprets them