OS III, Ex II, auditory lecture 1

Question 1

What are the 3 parts of the inner ear?

Answer 1

External, middle, inner

Question 2

Parts of external ear?

Answer 2

auricle, ceruminous glands

Question 3

Auricle is made of what?

Answer 3

elastic cartilage and sking

Question 4

Parts of auricle?

Answer 4

helix, antihelix, tragus, antitragus, concha and lobule

Question 5

What are ceruminous glands?

Answer 5

modified apocrine glands that secrete cerumen

Question 6

What is ear wax?

Answer 6

combo of cercumen, sebacous gland secreation, and desquamated meatal cells

Question 7

what are the external ear sebaceous glands associated with?

Answer 7

hairs

Question 8

What nerves innervate the external ear and external acoustic meatus?

Answer 8

greater auricular, lesser occipital, auriculotemporal, facial and vagus

Question 9

What innervates middle ear?

Answer 9

glossopharyngeal

Question 10

what connects tympanic cavity to nasopharynx?

Answer 10

auditory tube

Question 11

What opens the tubal cartilage?

Answer 11

levatory tensor paliti, and salpingopharyngeus

Question 12

what are used to amplify vibrations from membrane to oval window?

Answer 12

ossicles, malleus, incus, stabes

Question 13

Oval window leads to where?

Answer 13

cochlea

Question 14

What muscles are activated to dampen vibrations through ossicles?

Answer 14

tensor tympani: low frequency, stapedius: extream stapes vibrations

Question 15

What innervates the tensor tympani?

Answer 15

V3 - trigenimal

Question 16

What innervates stapedius?

Answer 16

VII - facial

Question 17

What is the chorda tympani?

Answer 17

Both a sensory and autonomic nerve that branches from facial VII to V#

Question 18

What nerve has sensory neurons that mediates taste from front of tongue?

Answer 18

Chorda tympani off the facial nerve

Question 19

What do the parasympathetics from the chorda tympani innervate?

Answer 19

Submandibular and sublingual salivary glands.

Question 20

Why may the corda tympani be impacted by otitis media, ear infection of middle ear?

Answer 20

because it passes between tympanic membrane and malleus, the first ossicle

Question 21

what is the center depression of tympanic membrane called?

Answer 21

umbo, its caused by malleous tension

Question 22

What should you be able to see if looking at ear drum auriscopically?

Answer 22

malleus, incus, stapes, cone of light, tence and flacid parts

Question 23

What can caouse otitus media?

Answer 23

Fluid buildup that blocks middle ear, negative pressue that pulls bacteria/virus up from pharynx.

Question 24

What could an invection of middle ear do?

Answer 24

perforate tympanic membrane, then spread through tegmen tympani cause brain abcss or meningitis.

Question 25

What conditon damages middle ear an mastoid by growing out of control?

Answer 25

Cholesteatoma

Question 26

What is choleasteaoma?

Answer 26

ear canal skin fills with cysts that migrate through porforation of tympanic membrane.can erode ossicles.

Question 27

what part of inneer has the hearing receptors?

Answer 27

Cochlea

Question 28

What is chochlea?

Answer 28

fluid filled spirally formed bony canal

Question 29

What are the three parts of cochlea?

Answer 29

Chochlear duct (scala media) scala vestibuli (top), scala tympani (bottom)

Question 30

What is the fluid of the cochlear ?

Answer 30

endo lymph that is screated by stria vascularis is in the cochlear duct while Periymph is in the scala vestibuli and tympani which are continuous.

Question 31

Endolymph is high in what ion?

Answer 31

K + - potassium

Question 32

Perilymph is high in what ion?

Answer 32

Na+

Question 33

what encloses the organ of corti?

Answer 33

Cochlear duct ie scala media

Question 34

What does the oval window vibration come in contact with?

Answer 34

the scalia vestibula and its perilymph that eventually becomes scalia tympani on its way to the round window.

Question 35

What is the sound tranduction for each part of ear?

Answer 35

External - air, Middle, Bone vibration, Inner - fluid vibration

Question 36

What laye does the organ of corti form on?

Answer 36

basilar membrane, an epithelial layer

Question 37

What covers organ of corti?

Answer 37

tectoral membrane

Question 38

what are the types of non-neural receptor cells?

Answer 38

both innner and outer hair cells

Question 39

What comes in contact with the tectoral membrane from the organ of corti?

Answer 39

stereocilia/microvili that activate sensory neurons of choclhelar nerve

Question 40

What causes bend in the sterreocilia part of receptors?

Answer 40

sound waves and their vertical oscilations of the basilar membrane.

Question 41

How does distortion of stereocilia produce hearing?

Answer 41

Distortion produce depolarization that causes release of transmitter to sensory neurons.

Question 42

What contains cell bodies of sensory neurons of the cochlear nerves?

Answer 42

spiral gnaglion

Question 43

How are tones differentiated ?

Answer 43

by the difference in basilar membrane stiffness and width. Narrow is stiff and detects high frequency while the further away membrane is wide and flexable and detects low frequencys.

Question 44

How does the difference in membrane stiffness detect specific sound.

Answer 44

sound frequency will only vibrate membrane at max amplitued in specific spots

Question 45

What do 95% of the sensory neuron axons in the cochlear nerve innervate?

Answer 45

inner hair cells, while the other 5% innervate outter hair cells.

Question 46

What do inner hair cells respond to?

Answer 46

basilar membrane movements at specific frequencies

Question 47

So what do outter hair cells do?

Answer 47

enhance weak auditory signals transduced by inner hair cells.

Question 48

What happens to outer hair cell in response to bending?

Answer 48

electromitile contraction followed by elongations, recoil amplifies.

Question 49

What type of feedback does the outer hair cell uses?

Answer 49

positive feedback

Question 50

What leads to hearing loss?

Answer 50

loud noise that damages outer hair cells.

Question 51

What increases our ability ito distinguish between frequencys that are close together?

Answer 51

outer hair cells, they sharpen sound peak from dull and rounded

Question 52

What is the primary auditory path?

Answer 52

Auditory nerve from cochlea - dorsal/ventral cochlear nuclei in medulla

Question 53

How many paths from medullary cochlear nuclei?

Answer 53

dorsal cochlear nucleus (red) and the ventral cochlear nucleus (black olive)

Question 54

what nuclei detects quality of sound so can distinguish between similar dounds?

Answer 54

red dorsal cochlear nucleus

Question 55

What does the superior olive ventral cochlear nucleus do?

Answer 55

Localizations

Question 56

Path from either the dorsal cochlear or the ventral cochlear?

Answer 56

up to lateral leminiscus, inferior colliculus, medial geniculate, primary suditory cortex in temp lobe.

Question 57

what localizes low frequencies?

Answer 57

time difference

Question 58

What localizes high frequency?

Answer 58

intensity

Question 59

What is the inferior colliculus for?

Answer 59

somatosensory for head orientation for sound localization.

Question 60

what does the medial geniculate body of thalamus do?

Answer 60

project sound. To cortex tonotopically, high frequency medial, low freq lateral.

Question 61

Where is the primay auditory cortex?

Answer 61

superior temporal lobe

Question 62

two streams of auditory association cortex

Answer 62

Ventral - speech comprehension, and dorsal - sensory motor for vocal artuculation.

Question 63

Ventral stream of auditory association cortex is for what?

Answer 63

comprehension of voice, language etc, wernikes area

Question 64

Wernikes area is for what?

Answer 64

Understanding speech : integrate auditory visual and somatosensory aspects of language

Question 65

What parts of written word are most importaint?

Answer 65

first and last letter, brain wil figure out the rest.

Question 66

What are involved in higher levels of auditory activity?

Answer 66

bilaterally, tenporal paretal and motor cortices.

Question 67

What is most involved in specific sides of brain?

Answer 67

singing is more right

Question 68

How does music in auditory cortex cause emotion?

Answer 68

It effects limbic regions: amygdala, cingulate cortex, hippocampus and insula

Question 69

what regulates outer and inner hair cells to regulate sensitivity to sound especially at low leves

Answer 69

Efferent olivochochlear nerurons from superior olive

Question 70

what would help supress background noise?

Answer 70

olivochochlear efferents

Question 71

what stimulates efferent olivarycochlear efferents?

Answer 71

input from cochlear nuclei, reticular formation, auditory cortex

Question 72

two types of deafness

Answer 72

conductive - tympanic membrane, sensorineural - damage to cochlea or cochlear portin of VIII

Question 73

What is subjective tinnitus?

Answer 73

sound sinsation without external stimulation.

Question 74

Broad Causes of tinnitus?

Answer 74

abnormal neural activity in path, change in primary auditory cortex,

Question 75

more specific causes of tinnitus

Answer 75

disease process, TMJ, neurological damage, infections, drug side effects.

Question 76

two types of tinnitus?

Answer 76

subjective and somatic

Question 77

What is somatic tinnitus

Answer 77

specific type of subjective, with 2 or more causes

Question 78

What can cause somatic tinnitus?

Answer 78

trigeminal relays afferent info, can send excitary projections.