1. THE EAR AND HEARING OBJECTIVES:
Explain how the ear converts sound waves into nerve impulses and identify all parts involved.
Describe the receptors and processes involved in the sense of equilibrium.

2. Collects and directs sound waves to eardrum
Pinna
Ear Canal
Eardrum
External Ear
Visible portion of ear
Collects and directs sound waves to eardrum
Eardrum boundary between external & middle ear
Wax – decreases growth of microorganisms
Small hairs – help prevent entry of foreign organisms

3. sound waves from ear drum to oval window Eustachian tube
Middle Ear
These bones transmit
sound waves from ear drum to
oval window
Eustachian tube
B/w middle ear & throat
Equalizes pressure on both sides of eardrum
Filled with air
Found w/in skull
Hammer
Stirrup
Anvil
Eustachian tube

4. Houses receptors for hearing and equilibrium Vestibule
Inner Ear
Houses receptors for hearing and equilibrium
Vestibule
Static equilibrium
Position of head with respect to gravity
Semicircular canals
Dynamic equilibrium
Rotational movements of head
Cochlea
Hearing
Converts sound waves into nerve impulses

5. HEARING))) 1. Sound waves cause Eardrum to vibrate
2. Vibrating Eardrum causes Hammer,
Anvil, and Stirrup to vibrate.
3. Stirrup causes oval window to vibrate
which causes fluid in cochlea to vibrate.
HEARING)))
4. Vibrating fluid causes basilar membrane
to vibrate
5. Vibrating basilar membrane pushes
hair cells against tectorial membrane
6. Bent hair cells generate nerve impulse
Nerve impulse transmitted to brain

6. HEARING))) 1. Sound waves cause Eardrum to vibrate
2. Vibrating Eardrum causes Hammer,
Anvil, and Stirrup to vibrate.
3. Stirrup causes oval window to vibrate
which causes fluid in cochlea to vibrate.
HEARING)))
4. Vibrating fluid causes the lower membrane to vibrate
5. Vibrating lower membrane pushes
hair cells against upper membrane
6. Bent hair cells generate nerve impulse
Nerve impulse transmitted to brain