The Ear

Question 0

Sound frequency

Answer 0

Measured in Hz

Cycles/sec

Question 1

What is sound?

Answer 1

Audible variations in air pressure

Question 2

Sound range

Answer 2

20 Hz to 20,000 Hz

Question 3

What is infrasound?

Answer 3

Low frequency sound that can be felt but not heard by humans

Question 4

Where is the organ of Corti located?

Answer 4

In the cochlea of the inner ear

Question 5

What is the auricle and what does it do?

Answer 5

Outer ear cartilage

Collects sound waves

Question 6

What is the external auditory meatus and what does it do?

Answer 6

Ear canal

Receives vibrations of sound waves and directs them towards tympanic membrane

Question 7

What is the function of the middle ear?

Answer 7

Amplifies and concentrates sound waves

Question 8

What is the tympanic reflex?

Answer 8

Protective mechanism
Requires loud and repetitive sound
Muscle tenses to keep ossicle from pushing stapes to oval window

Question 9

What is the tympanic cavity?

Answer 9

An air-filled space behind the eardrum that separates outer and inner ear

Question 10

What part of the ossicle is connected to the tympanic membrane?

Answer 10

Malleus

Question 11

What part of the ossicle connects the malleus to the stapes?

Answer 11

Incus

Question 12

What is the smallest bone in the body?

Answer 12

Stapes

Question 13

What part of the ossicle connects the incus to the oval window?

Answer 13

Stapes

Question 14

What structure is the entrance to the inner ear?

Answer 14

The oval window

Question 15

What structures does the Eustachian tube connect?

Answer 15

Middle ear to nasopharnyx

Equalizes pressure on both sides

Question 16

Why does our hearing decline with age?

Answer 16

Ossicles become ossified

Question 17

What is the bony canal in the temporal bone in inner ear?

Answer 17

Osseous labyrinth

Question 18

What is the membrane within the osseous labyrinth?

Answer 18

Membranous labyrinth

Question 19

How do lymphs of the ear differ?

Answer 19

Different ionic concentrations

Endolymph is high in K+

Question 20

Which fluid fills the space between the osseous and membranous labyrinth?

Answer 20

Perilymph

Question 21

Which fluid fills the membranous labyrinth?

Answer 21

Endolymph

Question 22

Why are there more outer hair cells?

Answer 22

They are responsible for amplification of sound

Question 23

Fluid in scala vestibule and scala tympani

Answer 23

Perilymph

Question 24

Fluid in scala media

Answer 24

Endolymph

Question 25

Basilar membrane contains:

Answer 25

: 16000 hearing receptor cells

Question 26

How the cochlea works:

Answer 26

: pressure from oval window -> pushes perilymph into scala vestibuli -> round window membrane bulges out

Question 27

What type of projection does the auditory nerve have?

Answer 27

Bilateral projection

Question 28

CNS structures associated with hearing

Answer 28

Inferior colliculi Medial geniculate nucleus of thalamus Insular cortex

Question 29

Lesion in the auditory cortex causes:

Answer 29

: normal auditory function because of bilateral projection

Question 30

With a cochlear implant :

Answer 30

: hair cells bypassed

Question 31

Utricle hair cells

Answer 31

Depolarization inward

Question 32

Saccular macula hair cells

Answer 32

Depolarization out wards

Question 33

What type of crystals are within the saccule and the utricle?

Answer 33

Calcium carbonate crystals

Question 34

Head movement is :

Answer 34

: opposite of fluid movement

Question 35

Push-pull arrangement of semicircular canals

Answer 35

Rotation causes excitation of a semicircular canal on one side and the inhibition of a semicircular canal on the other side

Question 36

What responds to gravitational pull?

Answer 36

Otoliths within gelatinous material

Question 37

What does the kinociliumdo?

Answer 37

Keeps otoliths embedded in gelatinous material

Question 38

Balance is a ________ pathway

Answer 38

Descending, controls motor

Question 39

All signals are _________ in brainstem and midbrain but __________ within cortex

Answer 39

Bilateral | Contralateral

Question 40

What are cupula?

Answer 40

Long rows with hair cells embedded in the crista ampullaris

Question 41

What is the vestibulo-ocular reflex?

Answer 41

Line of sight fixed on visual target Senses rotation of head and commands compensatory movement of eyes in opposite direction

Question 42

How are the EOMs excited by the VOR?

Answer 42

Semicircular canals -> vestibular nucleus -> CN nuclei -> EOMs

Question 43

What are the movement detectors of hearing and balance?

Answer 43

Periodic waves Rotational Linear force