1. How Does Your Ear “Catch” Sound Waves?
Your Ear Does Three Basic Things:
Channels the sound waves into your ear (the job of the pinna)
Vibrates due to the sound waves (the job of the ear drum and the bones of the inner ear)
Translates the vibration into an electric signal that your brain recognises as sound (the job of the cochlea)

2. The Ear (hearing) To Receive sound To Help us maintain our balance
The ear is a complex organ that has 3 functions:
To Receive sound
To Help us maintain our balance
To Detect the body’s spatial movement *

3. Video

4. The ear is divided into 3 sections:
The external ear
The middle ear
Inner ear

5. The outer ear The outer ear is composed of 2 parts:
The pinna (outer ear)
The auditory canal

6. The Pinna – Channels the Sound Waves Into Your Ear
The pinna is the outside part of the ear
It acts as a funnel that captures the sound
It also helps you to determine where a sound is coming from

7. The auditory canal
the auditory canal brings the sound to the middle ear
It protects the ear drum and internal ear from insects, bacteria and dust
The canal has hairs and secretes a wax that capture the foreign particles *

8. The Middle Ear The ear drum The ossicles The Eustachian tube
Composed of :
The ear drum
The ossicles
The Eustachian tube

9. 2. The Eardrum – Very sensitive membrane that vibrates When It is Hit By a Sound Wave
Sound waves travel down the ear canal and hit the tympanic membrane or ear drum (a cone-shaped piece of skin)
The ear drum vibrates when this happens
Eardrum seals the middle ear from the outside world.

10. The Ear Drum Is Connected to 3 Bones of the Inner Ear
There are three tiny bones inside your inner ear that vibrate whenever the ear drum vibrates
They “amplify” the vibrations (make the vibrations stronger)

11. The Ossicles (smallest bones in the body)
The first bone is called the “hammer”
The second is the “anvil”
The third is the “stirrup”
The bones transmit the sound vibrations of the ear drum to the inner ear *

12. The Eustachian tube
This tube is about 4cm long that leads from the middle ear to the pharynx
The tube is normally closed when one swallows or yawns
Its purpose is to equalize the pressure on each side of the ear drum *
Eustachian tube

13. The Inner Ear The inner has three parts The vestibule
The semicircular canals
The cochlea
Semi-circular canals
vestibule
stirrup
anvil
hammer
cochlea

14. The Vestibule The vestibule is located at the entrance to the cochlea
It contains nerve cells that are sensitive to body movements and the earth’s gravitational force
Info from the vestibule is processed in the cerebellum (balance and posture) *

15. Semi circular canals
3 rings filled with cochlear fluid oriented in different planes that allow us to orient ourselves in space *

16. When the head moves the liquid in the canals moves and this is sensed by the sensor cells and info is sent to and computed by the brain *

17. Cochlea- Changing a Vibration into an Electric Signal
The main hearing organ (shaped like a snail shell)
The cochlea is filled with liquid and lined with cilia that transform sound vibrations into nerve impulses
Each cilia reacts to its own frequency (high near the vestibule low at the extremity)
The sound info is sent to the brain via the auditory nerve *

18. The bones of the inner ear are connected to the cochlea
When the bones vibrate they create fluid waves in the cochlear fluid

19. Inside the cochlea are tiny hairs
When these hairs are moved (by the waves in the cochlear fluid) they send an electric signal through the cochlear nerve and to the brain
Your brain interprets these electric signals as a sound

20. Auditory Pathway (Sound Path)
Stimulus -> Pinna -> Auditory canal -> Eardrum -> Hammer -> Anvil -> Stirrup -> Vestibule ->Cochlea -> Cilia -> Nerve cells -> Auditory nerve -> Temporal lobe

21. Balance The ears also play an important role in balance
Inner ear continuously monitors the position of the head
The constant monitoring can, for example, help a diver find the water’s surface
The cells also help keep your balance when you are not moving (stabilize our posture)
(the ears and eyes work together in this…stand up and close your eyes and see what happens)

22. Balance in motion
Other cells in the inner ear maintain balance when our bodies are moving
They allow us to detect changes in speed and direction
Helping us walk and dance without falling over