Ears

Question 1

Cerumen

Answer 1

ceruminous glands, that protect the ear from infections and provides a barrier to insects and water

Question 2

Perilymph

Answer 2

fluid within the bony labyrinth, surrounding membranous labyrinth

Question 3

Endolymph

Answer 3

fluid within membranous labyrinth

Question 4

Modiolus

Answer 4

• part of the cochlea and its conical-shaped structure that consists of spongy (porous) bone located at the center of the cochlea
• contains spiral ganglion

Question 5

Maculae

Answer 5

static equilibrium receptors located perpendicular to each other in the utricle & saccule

Question 6

Saccule

Answer 6

a sac of membranous labyrinth

Question 7

Utricle

Answer 7

connected to the saccule by small duct

Question 8

Otolith

Answer 8

calcium carbonate crystals forming a layer of otolithic membrane

Question 9

Ampulla

Answer 9

enlarged swelling at the end of each semicircular canal

Question 10

what structures are in the inner ear?

Answer 10

• bony labyrinth-cochlea
• cochlear duct
• bony labyrinth
• perilymph
• membranous labyrinth
• endolymph
• cochlea
• scala vestibuli
• scala tympani
• spiral organ

Question 11

what structures are in the outer ear?

Answer 11

• auricular cartilage
• external auditory meatus
• cerumen/ ear wax
• pinna/ auricle

Question 12

what structures are in the middle ear?

Answer 12

• tympanic cavity
• tympanic membrane/ eardrum
• auditory ossicles/ ear bones
• malleus (“hammer”)
• incus (“anvil”)
• stapes (“stirrups”)
• oval (vestibular) window
• round (cochlear) window
• auditory tube (eustachian tube)

Question 13

What cranial nerve is responsible for equilibrium and hearing?

Answer 13

vestibulocochlear nerve (CN VIII)

Question 14

What cranial nerve is responsible for sight?

Answer 14

optic nerve (CN V)

Question 15

what are the 3 auditory ossicles?

Answer 15

• malleus
• incus
• stapes

Question 16

difference between round window & oval window?

Answer 16

round window:
covered by a secondary tympanic membrane, which bulges outward from the fluid movement

oval window:
it is filled base of the stapes, which pushes inward

Question 17

anatomic structures in hearing?

Answer 17

• sounds waves reaching the ear directed by the pinna goes to the external auditory meatus -> tympanic membrane
• tympanic membrane vibrated by the sound waves
• malleus, passes on and amplifies the vibrations (incus & stapes) to the windows
• Vibrations of the oval window (stapes) sets the perilymph into a wave motion
• that travels through the scala vestibuli & scala tympani to the round window
• The round window bulges into the middle ear and then back into the scala tympani, reversing the fluid wave movement
• Vibrations of the scala vestibuli & scala tympani generate wave motion of the endolymph within the cochlear duct displacing the hair cells of the spiral organ
• the movement of hair cells on spinal organ = nerve impulses
• the nerve impulse passes through the cochlear branch of the vestibulocochlear nerve (CN VIII) to the hearing centers in the brain

Question 18

anatomic structures in static equilibrium?

Answer 18

• concerned with “body (head) position” relative to gravity
• otolithic membrane is moved by the weight of the otoliths under the pull of gravity

Question 19

anatomic structures in dynamic equilibrium?

Answer 19

• when the head moves, pushes the cupula bending the hair cells
• sends impulses to the vestibular branch (via CN VIII)
• detecting angular rotational acceleration of declaration of head

Question 20

scala vestibuli

Answer 20

canal of bony labyrinth communicating with the vestibule

Question 21

hair (receptor) cells

Answer 21

receptor cells of the maculae carrying impulses to the vestibular branch of CN VIII

otolithic membrane: holds hair cells at which they are embedded in

Question 22

crista

Answer 22

receptor organ found in the ampulla of each semicircular duct

composed of hair receptor cells and supporting cells = senses motion of head

Question 23

vestibule

Answer 23

the central, expanded portion of the inner ear

Question 24

membranous labyrinth of the vestibule

Answer 24

consists of two sacs: saccule & utricle

Question 25

articular cartilage

Answer 25

- the elastic framework of the pinna & external auditory meatus - covered on both sides of the skin

Question 26

external auditory meatus

Answer 26

the passageway from the pinna to ear drum - vertical & horizontal canal

Question 27

middle ear/ tympanic cavity

Answer 27

contains auditory ossicles & opening of auditory tube

Question 28

tympanic membrane/ear drum

Answer 28

- thin, semitransparent partition between the external auditory meatus & the middle ear - ear drum is vibrated by sound waves

Question 29

auditory ossicles/ear bones

Answer 29

- 3 bones extend across the middle ear from the ear drum to the oval window of the cochlea - setting up vibrations in the fluid of the cochlea

Question 30

auditory tube (eustachian tube)

Answer 30

- the passageway between the middle ear & nasopharynx - functions: - equalize pressure on both sides of the eardrum - protecting from rupture - swallowing & yawning open auditory tubes = air into the middle ear

Question 31

bony labyrinth

Answer 31

series of cavities in the temporal bone - lined with the periosteum - divided into the vestibule, cochlea, and semicircular canals

Question 32

perilymph

Answer 32

fluid within the bony labyrinth, surrounding the membranous labyrinth

Question 33

membranous labyrinth

Answer 33

- a series of tubes and sacs within the bony labyrinth - Separates the two canals of bony labyrinth and forms the cochlear duct

Question 34

cochlea

Answer 34

- snail shell-like part of the inner ear associated with hearing - Consists of an outer bony coil and an inner membranous cochlear duct

Question 35

endolymph

Answer 35

the fluid within the membranous labyrinth

Question 36

spiral organ

Question 37

cochlear duct (scala media)

Answer 37

- the spiral canal extending from the base to the apex of the cochlea, between the canals of the bony labyrinth - filled with endolymph and contains the spiral organ - divides the bony spiral labyrinth into two channels: the scala vestibuli and the scala tympani

Question 38

bony labyrinth-cochlea

Answer 38

a bony, spiral canal making a number of turns around a central bony core