1. The Ear
Part 1: Structure and Function

2. Ears are sense organs that respond to sound.
Introduction
Ears are sense organs that respond to sound.
Your ear converts sound waves into electrical signals that your brain interprets.
The ear’s structure is designed to receive and transmit the sound waves…

3. The ear is divided into 3 major sections:
Basic Ear Anatomy
Outer Ear
The ear is divided into 3 major sections:
Contains the pinna, ear canal & ear drum
Middle Ear
Contains 3 bones: hammer, anvil & stirrup
Inner Ear
Contains the cochlea & auditory nerve

4. Ear Anatomy Outer Ear Middle Ear Inner Ear anvil stirrup pinna cochlea
hammer
auditory nerve
ear canal
ear drum
cochlea

5. Outer Ear

6. Outer Ear
The pinna is uniquely shaped to gather and focus sound waves and direct them into the ear.
The ear canal is a hollow tube that carries sound waves towards the ear drum.
Sound waves hit the ear drum, causing it to vibrate. The drum transmits these vibrations to the middle ear where they are amplified.

7. Ear Drum
Normal ear drum
Ripped ear drum

8. Middle Ear

9. Middle Ear
The middle ear has the smallest bones in the human body, the hammer, anvil and stirrup.
Their job is to amplify the vibrations of the ear drum and transmit them to the inner ear.
The stirrup taps on the cochlea of the inner ear at a location called the oval window.

10. Middle Ear Bones
Hammer
Anvil
Stirrup

11. Middle Ear Bones: An Analogy
Anvil
Hammer
Stirrup

12. Inner Ear

13. Inner Ear
The cochlea is a snail shaped tube that is lined with mechanoreceptors that respond to sound.
The mechanoreceptors are tiny hair cells that vibrate in response to sound waves passing by.
When the hair cells vibrate, they create an electric signal called a nerve impulse which travels to the auditory cortex of the brain via the auditory nerve.

14. The Cochlea

15. Hair Cells

16. Water Current (or Sound Wave)
Inside the Cochlea: An Analogy
Water Current (or Sound Wave)
Sea Grass Motion
(or Hair Cell Motion)
A seagrass meadow

17. High vs. Low Sounds
High pitch sounds carry more energy and travel further into the cochlea.
Lower pitch sounds carry less energy and travel less far into the cochlea.

18. A Final Look
Outer Ear
Middle Ear
Inner Ear

19. Summary: How We Hear
The ear is divided into 3 sections: the outer ear, middle ear and inner ear.
At the outer ear, sound waves are focused by the pinna down the ear canal to the eardrum.
The sound waves make the eardrum vibrate.
The vibrations are amplified by the 3 middle ear bones: the hammer, anvil and stirrup.
The stirrup transfers the vibrations to the cochlea within the inner ear.
The vibrations activate hair cells inside the cochlea, which send electrical signals to the brain along the auditory nerve.
The brain interprets these signals as sound.

20. Any Questions?

21. Quiz: Anatomy of the Ear5. 4. 3. 8. 6. 1. 2. 7. 9.

22. Quiz: Anatomy of the Ear
stirrup
anvil
hammer
auditory nerve
cochlea
ear canal
oval window
Eustachian tube
ear drum