Auditory Senses

What is hearing?

Our perception of sound

What is adequate stimulus for hearing?

Soundwaves

What is innervation hearing?

Auditory nerve

Where is the location of sound perception in the brain?

The auditory center

What are the 2 distinct functions of the ear?

Hearing and Equilibrium

What part of the ear catches soundwaves?

The outer/external ear

What do vibrations of the tympanic membrane result in?

Vibrations of fluidin the inner ear

What is the boundary between the outer and middle ear?

Tympanic membrane (Ear drum)

What part of the ear are the 3 ossicles located in?

The middle ear

What are the 3 ossicles?

• Malleus

• Incus

• Stapes

What are ossicles?

Tiny bones

What is the boundary between the middle and inner ear?

The oval window

Define the inner ear

Endolymph-filled membranous labyrinth suspended within a bony labyrinth

What is the name of the tube that equalizes pressure in the ear (Opens with pressure)?

The eustachian tube

What is the pinna?

The outer part of your ear (The skin). Think of huge elephant pinna

What are the 6 parts of the middle ear?

1. Tympanic membrane

2. Malleus

3. Incus

4. Stapes

5. Eustachian tube

6. Oval window

What are the 2 organs of the inner ear?

cochlea and semicircular canals

What is the cochlea?

A coiled structure in the inner ear that contains the receptors for hearing

What are semicircular canals?

Serve as the body’s balance organ

What is the function of the cochlea?

Converts sound pressure impulses from the outer ear into electrical impulses, which are passed on to the brain via the auditory nerve

How many cochlea does someone have in total?

Two (One in each ear)

How many chambers is the cochlea divided into?

Three

T/F The canals run the entire length of cochlea

True

What are the two large chambers present in the cochlea?

1. Scala vestibuli

2. Scala tympani

What is the smaller chamber in the cochlea?

Scala media

What is the name of the fluid that fills the two large chambers of the cochlea?

Perilymph

What connects the scala vestibuli and scala tympani at the apex/end of the cochlea?

Helicotrema

What does the scala media contain?

Basilar membrane

What is the scala media filled with?

endolymph

What is the basilar membrane?

A flexible membrane that is the receptor for hearing

Where is located on top of the basilar membrane?

Hair cells

What are the receptor cells in the cochlear duct imbedded in?

Bone

What is another name for the scala media?

cochlear duct

What is the organ of corti?

The sensory organ for hearing located in the cochlea of the inner ear

Describe the movement of the tectorial membrane

Moves a little bit but not much

Describe the movement of the basilar membrane

Moves up/down like waves

Where are the outer hair cells located?

They are pushed up against the tectorial membrane as basilar moves

What position are stereocilia at when at rest?

Erect

A ____ Frequency and ____ Amptitude sound wave looks longer

Low, High

A ____ Frequency and ____ Amptitude sound wave looks more compacted

High, Low

Describe the path that the soundwave takes in the ear

1. Sound vibrations strike the eardrum

2. The 3 ossicles vibrate and the footplate of the stapes moves at the oval window

3. Movement of the oval window causes the fluid inside the scala vestibuli and scala tympani to move

4. Fluid movement against the cochlear duct sets off the nerve impulses, which are carried to the brain via the cochlear nerve

Whats the first step in the path that the soundwave takes in the ear

Sound vibrations strike the eardrum

Whats the second step in the path that the soundwave takes in the ear

The 3 ossicles vibrate and the footplate of the stapes moves at the oval window

Whats the third step in the path that the soundwave takes in the ear

Movement of the oval window causes the fluid inside the scala vestibuli and scala tympani to move

Whats the Last step in the path that the soundwave takes in the ear

Fluid movement against the cochlear duct sets off the nerve impulses, which are carried to the brain via the cochlear nerve