Auditory Physiology

Question 1

What is the outer ear for?

Answer 1

Helps you collect sound

Question 2

What is the middle ear for?

Answer 2

Transmission of sound

Question 3

What is the inner ear for?

Answer 3

The conversion of sound into neural impulses

Question 4

What is the transmission of sound thru the external part of the ear?

Answer 4

Enters via pinna (auricle) and into the external auditory canal

Question 5

Then from the canal, where do vibrations reach?

Answer 5

The tympanic membrane

Question 6

What bone Is the middle ear?

Answer 6

Temporal bone of skull

Question 7

Sensation to the middle ear is provided by which nerve?

Answer 7

Glossopharngeal nerve (CN9)

Question 8

What does vibrations of the tympanic membrane cause?

Answer 8

The ossicles to vibrate

Question 9

What are the ossicles?

Answer 9

3 bones
Malleus
Incus
Stapes
MIS

Question 10

Ossicles
What bones are they?
What do they have between them?

Answer 10

Smallest bones of the body

Synovial joints between them

Question 11

What do the ossicles then hit on?

Answer 11

Transfer the vibrations to the oval window of the scala vestibuli

Question 12

The amount of energy transmitted to the inner ear can be lessened by contraction of what 2 small muscles?
What are they innervate by?
What do they connect to?

Answer 12

Tensor tympani
Mandibular division of trigeminal
Attaches to malleus

Stapedius
Facial nerve (CN7)
Stapes

Question 13

These muscles protect the inner ear from….

But can’t protect it from….

Answer 13

Continuous loud noise

Sudden intermittent loud sounds

Question 14

What is the inner ear called?

Answer 14

The cochlea (organ of hearing)

Question 15

What is the cochlear duct filled with?

Answer 15

Endolymph

Extracellular fluid with high conc of K+ & low Na+

Question 16

What is scala vestibuli and tympani filled with?

Answer 16

Perilymph

Similar to CSF

Question 17

When waves of pressure get to the oval window of the scala vestibuli, where does it go?

Answer 17

Scala vestibuli—-> helicotrema —-> scala tympani —-> round window (relieves pressure)

Question 18

Where is the Basilar membrane?

Answer 18

Above scala tympani and below cochlear duct

Question 19

The base of the Basilar membrane is….. thus sensitive to …..

Answer 19

Narrow and stiff

High frequency’s

Question 20

The apex of the Basilar membrane is….. thus sensitive to …..

Answer 20

Wider and less stiff

Low frequency’s

Question 21

What happens to the stereocilia on basilar membrane?

Answer 21

Bent against stationary tectorial membrane

Question 22

What neurotransmitter is released by the hair cells?

Answer 22

Glutamate onto afferent neurones

Question 23

This results in APs in the neurons, the axons of which join to form the….

Answer 23

Cochlear branch of the vestibulocochlear nerve

Question 24

What is the path of the vestibulocochlear nerve, the cochlear branch?

Answer 24

Cochlear nuclei
Superior olivary nucleus
Inferior colliculus
Medial geniculate body 
Primary auditory cortex, in wernickes area

Question 25

Where is the primary auditory cortex found and why?

Answer 25

Temporal lobe Surrounded by wernickes area Auditory info is interpreted and understood here

Question 26

What is a way to remember the pathway?

Answer 26

I’M Auditory Inferior colliculus Medial geniculate body Auditory info

Question 27

Then what must the pathway be for vision?

Answer 27

Superior colliculus | Lateral geniculate body

Question 28

What does the Corda tympani do and run through?

Answer 28

Branch of the CN5 Conveys taste info from tongue Runs through middle ear to carry taste messages to brain

Question 29

Inflammation of the facial nerve can lead to pain where?

Answer 29

Behind the ear | Also paralysis of facial muscles and failure to close eye

Question 30

What is wernickes area important for? | What happens if wernickes area is damaged?

Answer 30

Processing and understanding language in the brain | Not able to understand questions and speech will be incomprehensible

Question 31

What does the vestibular system comprise of?

Answer 31

3 semicircular canals filled with endolymph 2 sac like swellings, the utricle and saccule (otolithic organs) Hair cells

Question 32

What do the otolithic organs provide info about?

Answer 32

Linear acceleration | Changed in head position in relation to gravity

Question 33

What nerve is supplied by the vestibular system?

Answer 33

Vestibular branch of the vestibulocochlear nerve (CN8)

Question 34

What is vestibular info used for?

Answer 34

Control of eye muscles Reflex mechanisms of maintaining upright posture and balance Conscious awareness of the position and acceleration of the body - proprioception