Hearing, Balance And Coordination

Question 1

What is pitch discrimination ?

Answer 1

Differentiate high pitches (High freq) and low pitches (low freq)
Lose high pitch first because close to oval window so hair cells constantly being used (teen)
Low freq = old age

Question 2

What is sound ?

Answer 2

Pressure waves in the air.

Question 3

How does pressure waves in tympanic duct result in sound ?

Answer 3

Go through cochlear duct 
Hair cells push against tectorial membrane 
Action potential 
Signal sent to Brain 
Converted to sound

Question 4

What are the membranes in the organ of corti?

Answer 4

Tectorial Membrane = lots of sensitive hair cells and membrane folded on top
Basilar membrane - support and surround hair cells

Question 5

What are the two ducts of the cochlea ?

Answer 5

Oval window (at top ) = vestibular ducts 
Round window (at bottom) = tympanic duct

Question 6

Where are the pressure waves extinguished ?

Answer 6

Round window is where pressure waves are extinguished

Question 7

What happens at the oval window ?

Answer 7

Vibrated by stirrup at the opening of inner ear

Question 8

Where do sound impulses travel to to get to the brain ?

Answer 8

The vestibulocochlear nerve

Question 9

Where does the auditory tube lead to? And purpose ?

Answer 9

Links to throat (underneath the oval window)

Allows pressure to be equalised so ear drums aren’t ruptured

Question 10

What is the cochlear ducts?

Answer 10

Membranous lybranyth filled with endolymph

Question 11

What is the bony labyrinth ?

Answer 11

On outside, filled with perilymph fluid

Question 12

What is an ampulla ? What does it detect?

Answer 12

Each canal has a swollen ampulla
Each ampulla contains a crista bound to a swaying cupola
Crista attached to bundle of nerves (vestibulochloear nerve)
Movement of the head displaces the cupula because endolymph filled cupula which causes hair to bend (like seaweed in sea waves)
this stimulates the sensitive hair cells
SENSES ROTATION and BALANCE
The crista ampullaris itself is a cone-shaped structure, covered in receptor cells called “hair cells”. Covering the crista ampullaris is a gelatinous mass called the cupula. Upon angular acceleration (rotation), the endolymph within the semicircular duct deflects the cupula against the hair cells of the crista ampullaris. The hair cells respond by stimulating neurons that innervate them.

Question 13

How many loops are there in the semi circular canal?

Answer 13

3 loops at 90 degrees apart from one another so pick up any movement of head from any plane

Question 14

What if the swollen area of the inner ear before the semi circular canal ?

Answer 14

Vestibule - sensory organs of equilibrium = knowing where your head is in space even with eyes closed -

Question 15

What is the name of the specialised hair cells in the semi circular canals ?

Answer 15

Stereocillia - part of balance section

Question 16

How many bones in the inner ear and what is it filled with?

Answer 16

Inner ear filled with air and equivalent to atmosphere pressure which connects to auditory tube
3x tiny bones which link sound waves from ear drums to inner ear

Question 17

What happens when sound waves enter the ears and name the three bones

Answer 17

Sound waves - pressure waves
When waves hit ear drum then ear drum vibrates then pushes against 1st of bones - hammer
Then pushes against 2nd bone = incus then passes vibration onto the stirrup (3)
Vibrates against a membrane that communicates with inner ear

Question 18

What protects ear when volume too loud?

Answer 18

Tiny bones are stabilised with ligaments and tiny muscles that don’t vibrate too loudly is noise level is too high

Question 19

What is the outer ear (folded cartridge) called

Answer 19

Pinna