Hearing

Question 1

Audiology

Answer 1

The study, assessment, management and rehabilitation of adults and children with hearing, auditory and balance disorders.

Question 2

Loss of signal

Answer 2

Reduced audibility, usually higher frequencies

Question 3

Loss of clarity

Answer 3

Difficulty picking out sounds from noise

Question 4

Loss of amplitude sensitivity

Answer 4

Harder to hear quieter sounds

Question 5

If you loose frequency range what is the kind of sounds most likely to go

Answer 5

Higher frequency sounds
Eg fricative sounds

Question 6

What does spectral detail mean

Answer 6

Inability to differentiate different frequencies of sound

Question 7

What is frequency measured in

Answer 7

Hertz

Question 8

How do you calculate Hz

Answer 8

1 / period (in seconds)

Question 9

What is the function of the central auditory system

Answer 9

-function is to transform the neural code from the periphery into meaningful precepts of the world
-there are a series of auditory areas (primary, secondary) responsible for sound processing
-these regions project to different sensory and cognitive systems

Question 10

2 Ear canal functions

Answer 10

-channel sound into the tympanic membrane
-protect the tympanic membrane

Question 11

How does the ear canal protect the tympanic membrane

Answer 11

-wax and hair traps dirt and foreign objects
-epithelial skin cells migrate slowly outwards, carrying wax and debris out of the ear canal

Question 12

2 middle ear functions

Answer 12

Impedance matching
Acoustic reflex

Question 13

What does impedance matching mean

Answer 13

There is a mismatch in mediums. Energy comes in as pressure changes and ends up being fluid vibrations in the cochlea

Question 14

What does acoustic reflex mean

Answer 14

Middle ear muscles contract in response to loud sounds. Reducing energy transferred
Thought to protect cochlea from damage

Question 15

Inner ear function

Answer 15

Oval window - interface between middle ear and cochlea
Stapes is fused to the oval window
Movement of stapes causes vibration of the cochlea fluids

Question 16

What does the tectorial membrane in the cochlear do

Answer 16

Extends above organ of corti
Made from gelatinous material

Question 17

Reissners membrane in cochlear

Answer 17

Separates fluid in scala media from that in scala vestibulaire
Very thin

Question 18

Helicotrema of cochlea

Answer 18

Hole that connects scala vestibulu and scala tympani

Question 19

Basilar membrane

Answer 19

One membrane forming the cochlear partition
Movement of cochlear fluid causes basilar membrane to move to

Question 20

How many rows of outer hair cells do you have

Answer 20

Three rows

Question 21

What do the outer hair cells act as

Answer 21

Cochlear amplifier

Question 22

How do the outer hair cells act as a amplifier

Answer 22

-steroilia movement causes +ve ions (potassium primarily) to enter cell from scala media
-this causes depolarisation of the cell
-which causes the cell body to change shape (length) in a process called electromotility

Question 23

Amplification

Answer 23

-largest stereocilia of the outer hair cell is embedded In the tectorial membrane. When the hair cell shortens (due to polarisation) they pull the tectorial membrane down toward the basilar membrane
-this amplifies the motion of the basilar membrane

Question 24

Inner hair cells

Answer 24

-around 3500 in the cochlea
-converts movement of the tectorial membrane into action potentials
-movement of the stereocilia causes the same depolarisation as for the outer hair cells
-this triggers a release of neurotransmitter at the base of the cell

Question 25

Hair cell loss

Answer 25

-outer hair cells are susceptible to damage (drugs/noise)
-leads to a loss of amplification so we loose sensitivity to sounds ie hearing loss
-electromotility decreases with age (Presbycusis)

Question 26

Cochlear implants

Answer 26

-as a treatment for profound deafness, an array of electrodes on a wire can be inserted which will send electrical signals to the auditory nerve
-bypasses the outer ear, middle ear and the cochlear hair cells.