The Ear And Cn Viii: Anatomy, Auditory And Vestibular Microanatomy & Function

Front 1

What is the auricle composed of?

Back 1

elastic cartilage

Front 2

What two nerves provide sensory innervation to the auricle and external acoustic meatus?

Back 2

1. auriculotemporal n.(V3)
2. greater auricular n. (branch of the cervical plexus, C2-3)

Front 3

What is the blood supply to the auricle and external acoustic meatus? What are these vessels branches of?

Back 3

1. posterior auricular artery
2. superficial temporal artery
Both are branches of the external carotid a.

Front 4

the external acoustic meatus stretches from the _________ to the ___________.

Back 4

concha to the tympanic membrane

Front 5

In the external acoustic meatus: the lateral 2/3 of the canal is _____________, while the medial 2/3 is __________.

Back 5

cartilage
bone (temporal bone)

Front 6

the skin lining the external acoustic meatus is continuous with the ___________.

Back 6

tympanic membrane

Front 7

What portion of the malleus articulates with tympanic membrane?

Back 7

the handle and lateral processes of the malleus articulate with the tympanic membrane

Front 8

The lateral wall of the middle ear is formed by the ______________.

Back 8

tympanic membrane

Front 9

what is the sensory innervation to the external surface of the tympanic membrane?

Back 9

1. auriculotemporal n. (V3)
2. auricular branch of CN X

Front 10

what is the sensory innervation to the INTERNAL surface of the tympanic membrane?

Back 10

glossopharyngeal n. (IX)

Front 11

List the bony contents of the tympanic cavity.

Back 11

malleus, incus, stapes

Front 12

Name the muscles (2) found in the tympanic cavity. What is the innervation to each?

Back 12

1. stapedius - branch of facial n. (VII)
2. tensor tympani - mandibular n. (V3)

Front 13

The chorda tympani is a branch of which nerve? What information does it carry?

Back 13

facial n. (VII)
carries taste from anterior 2/3 of tongue

Front 14

the tympanic plexus of nerves arises from the ___________ nerve and from sympathetic fibers of__________.

Back 14

1. glossopharyngeal n. (IX)
2. the internal carotid plexus

Front 15

What provides sensory innervation to the mucosa of the tympanic cavity, the pharyngotympanic tube and the mastoid air cells?

Back 15

tympanic plexus

Front 16

The tegmentum tympani separates __________ from ________. This is known as the __________ recess.

Back 16

separates the tympanic cavity from the middle cranial fossa.
epitympanic recess

Front 17

The floor of the tympanic cavity separates ___________ from ___________.

Back 17

separates the tympanic cavity from jugular bulb

Front 18

the lateral wall of the tympanic cavity consists of _________.

Back 18

the tympanic membrane

Front 19

The medial wall of the tympanic cavity consists of _________.

Back 19

the oval window, stapes base, cochlear promontory, round window.

Front 20

The anterior wall of the tympanic cavity opens into _____1_____ and ______2_____.

Back 20

1. pharyngotympanic tube
2. canal for tensor tympani

Front 21

The posterior wall of the tymp. cavity provides passage between the ________ and _________. This passage contains _________.

Back 21

tympanic cavity and the mastoid antrum.
Contains a canal for the facial n.

Front 22

Where exactly is the tympanic plexus located?

Back 22

The tympanic plexus sits on the PROMONTORY. (not on the tympanic membrane as many think)

Front 23

The chorda tympani runs anterior -> posterior, and it weaves between what two important structures?

Back 23

the tensor tympani and malleus

Front 24

What are the contents of the bony labyrinth ? (3)

Back 24

1. Cochlea
2. Vestibule
3. Semicircular canals

Front 25

the bony cells in the inner ear contain ___________.

Back 25

perilymph

Front 26

The semicircular canals, utricle and saccule are components of the _______________.

Back 26

vestibular system

Front 27

Where are otolith organs called maculae found? Which system are they involved with?

Back 27

found in the utricle and saccule of the vestibular system.

Front 28

The ________ maculae are found on the lateral wall, whereas the _________ maculae are found on the floor.

Back 28

Utricle maculae on lateral wall
Saccule maculae on floor

Front 29

Receptor cells for the vestibular system are mostly __________, with one long _____________.

Back 29

microvilli
kinocilium

Front 30

cells that are surrounded by one large, cup shaped afferent nerve ending are ________ (Type I or II) cells.

Back 30

Type I

Front 31

cells that are surrounded by multiple afferent nerve endings are called _________ (Type I or II) cells.

Back 31

Type II

Front 32

Efferent endings on both type I and II cells are ________ (+) or (-).

Back 32

(-)

Front 33

1. The surface covered with calcium carbonate crystals known as ____________.
2. What lies directly beneath the otolith layer?

Back 33

1. Otoliths
2. a gelatinous, glycoprotein layer

Front 34

The otoliths pull the gelatinous covering in response to _______________.

Back 34

changes in position related to gravity.

Front 35

Hair cells deflected TOWARDS the kinocilium causes ___________ (+) or (-), whereas hair cells deflected AWAY from the kinocilium cause ___________. (+) or (-)

Back 35

Towards - excitation
Away - inhibition

Front 36

_________ are sensitive to gravity; they help to percieve movement and orientation in space. They are also used to maintain equilibrium and balance.

Back 36

Maculae

Front 37

Semicircular ducts lie within the semicircular canals; they have enlarged regions called ampulae that contain ________________.

Back 37

cristae ampullaris receptors

Front 38

The semicircular ducts are very similar to the maculae. What is the difference?

Back 38

Walls are thicker
gelatinous convering much thicker and is called the cupula.
There are no otoliths

Front 39

What will cause the cupula to bend?

Back 39

acceleration or deceleration of the head.

Front 40

Once the cupula bends what happens?

Back 40

Bending of the cupula causes bending of the hair cells; this causes either depolarization (bending towards the kinocilium) or hyperpolarization (bending away from the kinocilium)

Front 41

What is the proposed function of the endolymphatic sac and duct?

Back 41

thought to absorb endolymph and remove debris via endocytosis

Front 42

The cochlear duct, organ of Corti and scala vestibuli are components of _________.

Back 42

the auditory system

Front 43

The scala vestibuli and tympani are filled with ________.

Back 43

perilymph

Front 44

The stapes transmits sound waves to the inner ear via ___________.

Back 44

the oval window

Front 45

Once transmitted by the oval window, sound waves cause shearing and oscillation of ____________.

Back 45

The organ of Corti

Front 46

What structure relieves wave pressure in the inner ear?

Back 46

the round window

Front 47

What is the stria vascularis and what is it's function?

Back 47

vascularized epithelium in the lateral wall of the Cochlear Duct. It controls the ion content of endolymph.

Front 48

The Organ of Corti is separated from the Scala Vestibuli by the ________ membrane; also separated from the Scala Typmani by the ___________ membrane.

Back 48

Vestibular membrane
Basilar membrane

Front 49

Is there a kinocilium in the organ of Corti?

Back 49

NO. There is one "tallest hair" that has a basal body

Front 50

_________ cells are found between inner and outer hair cells: they form an "inner tunnel" between the outer and inner hair cells. Why is this tunnel important?

Back 50

Pillar Cells
The inner tunnel is used in sound transduction

Front 51

Which ganglion innvervates the inner and outer hair cells of the Organ of Corti?

Back 51

The Spiral Ganglion

Front 52

In terms of auditory function: what occurs during Compression? How about rarefaction?

Back 52

Compression - during lateral shearing of stereocilia, the tips deflect away from the basal body.
Rarefaction - membranes and stereocilia move in the opposite direction

Front 53

Movement of the sterocilia causes ____________ in the hair cells.

Back 53

depolarization and neurotransmitter release

Front 54

Depolarization and action potential release of the hair cells causes _____________.

Back 54

an action potential to fire in the axons of the spiral ganglion neurons

Front 55

_______ frequency sound in detected at the base of the cochlear duct, whereas ________ frequency sound in detected at the apex of the cochlear duct.

Back 55

High - at base
Low - at apex