Ear, hearing, and vestibular

Question 1

What is audition?

Answer 1

Process to perceive the frequency and intensity of the sound and its localization in the space

Question 2

What are the parts of the external ear?

Answer 2

Auricle or pinna
External auditory canal

Question 3

What is the main function of the external ear?

Answer 3

Collection and funneling of sound

Question 4

What are the structures in the middle ear?

Answer 4

Tympanic membrane
Tensor tympani muscle
Stapedius muscle
Ossicles
Eustachian tube
Nerves
Blood vessels
Lymphatics

Question 5

What are the three ossicles?

Answer 5

Malleus
Incus
Stapes

Question 6

What are the functions of the middle ear?

Answer 6

Impedance matching
Protection of inner ear structures
Static pressure equilibration
Preferential route of conduction

Question 7

What is impedance matching?

Answer 7

Ability of wave to be transferred from are to liquid in the ear

Question 8

What aids in impedance matching in the ear?

Answer 8

Area of tympanic membrane compared to oval window
Lever advantage formed by malleus on incus

Question 9

What is the tympanic reflex?

Answer 9

Also called attenuation or acoustic reflex

Activated by sounds that are intense, low frequency, and of long duration
Reduces sensitivity to own voice
Contraction of tensor tympani and stapedius

Question 10

What is the function of the eustachian tube?

Answer 10

Equalize pressure to allow for a state conducive to efficient sound conduction

Question 11

What are the parts of the inner ear?

Answer 11

Cochlea
Vestibular apparatus

Question 12

What is perilymph?

Answer 12

Fluid in bony labyrinth that is similar to ECF

Question 13

What is endolymph?

Answer 13

Fluid in membranous labyrinth that is similar to ICF

Question 14

What is the receiver for sound waves?

Answer 14

Auditory hair cells on the organ of Corti

Question 15

What are the components of sound?

Answer 15

Amplitude
Frequency
Loudness
Pitch

Question 16

What causes pitch discrimination?

Answer 16

Displacement of basilar membrane in organ of Corti

Question 17

Where does the organ of corti project?

Answer 17

To bipolar spiral ganglion to auditory N component of CN VIII to cochlear nucleus

Question 18

Where does the cochlear nucleus project?

Answer 18

Superior olivary nucleus bilaterally

Question 19

Where does the superior olivary nucleus project for audition?

Answer 19

Fibers ascend in lateral lemniscus to inferior colliculus in midbrain

Question 20

Where does the inferior colliculus project for audition?

Answer 20

To medial geniculate nucleus of thalamus to auditory cortex

Question 21

What are the auditory association areas?

Answer 21

22, 21, 20, 42

Question 22

What is the primary auditory cortex area?

Answer 22

41

Question 23

What areas are concerned with interpretation and integration of auditory impulses?

Answer 23

21, 20 and 42

Question 24

What does the localization of sound depend on?

Answer 24

Interaural time difference
Interaural intensity difference

Question 25

Where are the interaural time differences processed?

Answer 25

Binaural inputs to medial superior olive

Question 26

Where are the interaural intensity differences processed?

Answer 26

Binaural inputs to lateral superior olive and medial nucleus of the trapezoid body

Question 27

What are the two types of hearing loss?

Answer 27

Conductive Sensorineural

Question 28

What systems are involved in the vestibular apparatus?

Answer 28

Sensory input from vision Proprioception Vestibular system

Question 29

What structures make up the bony labyrinth?

Answer 29

Cochlea Vestibule Semicircular canal

Question 30

What structures make up the membranous labyrinth?

Answer 30

Cochlear duct Saccule Utricle Semicircular ducts

Question 31

Where is the membranous labyrinth located in the inner ear?

Answer 31

Within the bony labyrinth

Question 32

What structures make up the vestibular apparatus in the inner ear?

Answer 32

Semicircular canals Utricle Saccule

Question 33

What is the utricle concerned with?

Answer 33

Linear acceleration and static equilibrium in the horizontal dimension

Question 34

What is the saccule concerned with?

Answer 34

Linear acceleration and static equilibrium in the vertical dimension

Question 35

What are the semicircular canals concerned with?

Answer 35

Angular/rotational acceleration

Question 36

What structure of the labyrinths houses the utricle and saccule?

Answer 36

Vestibule

Question 37

What are the sensory receptors in the semicircular canals?

Answer 37

Cristae ampullaris

Question 38

What are the sensory receptors in the utricle and saccule?

Answer 38

Macula - otolithic organ

Question 39

What are the three semicircular canals?

Answer 39

Horizontal/lateral Superior/anterior Inferior/posterior

Question 40

What type of cells make up the crista ampullaris?

Answer 40

Neuro-sensory epithelial cells (hair cells) Supporting/sustentacular cells Cupula

Question 41

What is the cupula?

Answer 41

Gelatinous mass that surrounds the hair cells and supporting cells, closing of the ampulla of the semicircular canal

Question 42

What are the two types of micro cilia in the vestibular system?

Answer 42

Kinocilium - longest Stereocilia - length varies

Question 43

What causes hyper- or depolarization?

Answer 43

Movement of cilia from the movement of fluid in response to movement of the body

Question 44

What is the equilibratory vestibular statokinetic reflexes?

Answer 44

Coordinate eyeball movement with head movements

Question 45

How is the vestibular system related to muscle tone?

Answer 45

Maintains muscle tone reflexly through the vestibulospinal tract

Question 46

What makes the otolithic membrane unique?

Answer 46

Presence of calcium carbonate crystal called otoliths

Question 47

What is the gravity receptor in the inner ear?

Answer 47

Macula

Question 48

What is the innervation of the vestibular apparatus?

Answer 48

Vestibular N of CN VII from bipolar vestibular ganglion

Question 49

Where does the vestibular N terminate?

Answer 49

Vestibular nuclei

Question 50

Where does the vestibular nuclei project?

Answer 50

Through medial longitudinal bundle in ascending to vestibuloocular tract, vestibulocerebellar tract, and vestibulocortical fibers, and descending branches to vestibuloreticular fibers, and descending medial longitudinal fasciculus Lateral vestibulospinal tract

Question 51

Where do the vestibulocortical fibers project?

Answer 51

Temporal lobe

Question 52

Where to the descending medial longitudinal fasciculus fibers from vestibular nuclei project?

Answer 52

To cervical segments of spinal cord and lateral vestibulospinal tract

Question 53

Where does the vestibuloocular tract terminate?

Answer 53

CN III, IV, and VI cranial nuclei to eyes

Question 54

Where does the vestibulocerebellar tract terminate?

Answer 54

Flocculonodular lobe

Question 55

Where does the vestibulospinal tract terminate?

Answer 55

Vestibuloreticular fibers

Question 56

What are the functions of the vestibular apparatus?

Answer 56

Control of tone, posture, equilibrium Guide cerebellum with labyrinth impulses Guide cerebrum for conscious vestibular sensation Statokinetic reflex Statotonic reflex

Question 57

What are the effects of a labrinthectomy?

Answer 57

Loss of equilibrium Convulsive eye movements Profound muscular weakness Vertigo

Question 58

What are causes of nystagmus?

Answer 58

Vestibular nystagmus Cerebellar nystagmus Caloric nystagmus Positional alcohol nystagmus