ALH 110: Chapter 17 (Sensory Organs PART 2 EAR)

what is the pinna/auricle

where sound waves enter; the flap of the ear that serves as the projecting part of the ear

what is the external auditory meatus

the auditory canal; leads from the pinna/auricle and is lined with glands that secrete cerumen

what is cerumen

a yellowish brown waxy substance

what is the functionality of cerumen

to lubricate and protect the ear canal

how do sound waves travel to the middle ear

sound waves move through the external auditory meatus (auditory canal) and strike the tympanic membrane (eardrum) between the outer and middle ear

what is the tympanic membrane

the eardrum; stricken with sound waves from the outer ear and rattles ossicles (three small bones) that conduct sound waves through the middle ear

what are ossicles

three small bones that conduct sound waves from the tympanic membrane through the middle ear; include the malleus, incus, and stapes

what is the malleus

the first of three ossicles to vibrate

what is the incus

the second of three ossicles to vibrate

what is the stapes

the third of three ossicles to vibrate

what is the oval window

the separation from the middle to inner ear; touched by stapes when it moves

what is the auditory/eustachian tube

a canal that leads from the middle ear to the pharynx, opens upon swallowing

what is the functionality of the auditory/eustachian tube

to prevent damage to the eardrum and shock to the middle and inner ears

what is the labyrinth

the inner ear; characterized by its circular, maze-like structure

how does sound travel from the middle ear to the inner ear

sound waves are transmitted by the movement of the tympanic membrane to the ossicles, and reach the inner ear via the fluctuations of the oval window

what is the cochlea

a bony, snail-shell shaped structure that leads from the oval window

the cochlea contains special auditory liquids called

perilymph and endolymph

what is the organ of Corti

a sensitive auditory receptor present in the cochlea

what is the function of the organ of Corti

its tiny hair cells receive vibrations from the auditory liquids and relay said sound waves to the auditory nerve fibers

what are the auditory nerve fibers

auditory center of the cerebral cortex; impulses from the cochlea’s organ of Corti are interpreted

what is the vestibule

a connector for the cochlea and semicircular canals (balance)

what does the vestibule contain

saccule and utricle, endolymph, and sensitive hair cells

how does the vestibule ensure equilibrium (balance)

the endolymph and hair cells fluctuate in response to head movements, which sends impulses in nerve fibers to the brain, which are then sent to muscles to ensure equilibrium is maintained

how does sound travel from the ear to the cerebral cortex

1. pinna (begin outer ear)

2. external auditory canal

3. tympanic membrane (end outer ear)

4. malleus (begin middle ear)

5. incus

6. stapes

7. oval window (end middle ear)

8. cochlea (begin inner ear)

9. auditory liquids and receptors in the organ of Corti

10. auditory nerve fibers (end inner ear)

11. cerebral cortex (brain)

auditory canal

channel that leads from the pinna to the eardrum; auditory meatus

auditory nerve fibers

carry impulses from the inner ear to the cerebral cortex (brain); composed of vestibulocochlear nerve (cranial nerve VIII)

auditory tube

channel between the middle ear and the nasopharynx; eustachian tube

auricle

the protruding part of the external ear; auricle

cerumen

waxy substance secreted by the external ear; earwax

endolymph

fluid within the labyrinth of the inner ear

define incus

anvil

define malleus

hammer

perilymph

fluid contained in the labyrinth of the inner ear

define stapes

stirrup

what two structures are within the vestibule

saccule and utricle

acous/o

hearing

audi/o

hearing; the sense of hearing

-gram

a record, image, or tracing produced by a diagnostic machine

audit/o

hearing

-ory

pertaining to

aur/o, auricul/o

ear

post-

after, behind, following

cochle/o

cochlea

mastoid/o

mastoid process

what is the mastoid process

a conical prominence of the temporal bone behind the ear

define conical

having the shape of a cone

define temporal

of or situated in the temples of the head

myring/o

eardrum, tympanic membrane

-tomy

cutting, incision, surgical incision

ossicul/o

ossicle

-plasty

surgical repair, reconstruction, molding, reshaping

ot/o

ear

salping/o

eustachian tube, auditory tube (fallopian tubes)

define larynx

voice box

define pharynx

throat

staped/o

stapes (third bone of middle ear)

tympan/o

eardrum, tympanic membrane

vestibul/o

vestibule

-acusis, -cusis

hearing

hyper-

excessive, high, beyond, above normal

-meter

instrument to measure

-otia

ear condition

acoustic neuroma

benign tumor in the acoustic vestibulocochlear nerve (eighth cranial nerve) in the brain

symptoms of acoustic neuroma

tinnitus, vertigo, decreased hearing

cholesteatoma

collection of skin cells and cholesterol in a sac within the middle ear

steat/o

fat

characteristics of cholesteatoma

foul-smelling discharge and perforations of the tympanic membrane

deafness

loss of the ability to hear

nerve deafness (sensorineural hearing loss)

results from impairment of the cochlea or auditory nerve

conductive deafness

results from the impairment of sound wave transmission from the external ear to the cochlea

meniere disease

disorder of the labyrinth of the inner ear; characterized by cochlear hydrops and vestibular hydrops

what are cochlear hydrops

elevated endolymph pressure within the cochlea

what are vestibular hydrops

elevated endolymph pressure within semicircular canals

symptoms of meniere disease

tinnitus, heightened sensitivity to loud sounds, progressive hearing loss, headache, nausea, and vertigo

otitis media

inflammation of the middle ear

acute otitis media

infection of the middle ear, often following a URI

URI

upper respiratory infection

suppurative otitis media

pus formation as bacteria enters the ear

serous otitis media

noninfectious inflammation with accumulation of serous fluid; results from dysfunctional or obstructed auditory tube

otosclerosis

hardening of the bony tissue in the middle ear; when bone forms around the oval window and caused ankylosis of the stapes bone

define ankylosis

stiffening

define prosthesis

artificial part

define fenestrated

opened

tinnitus

sensation of noises in the ears without an external source, caused by irritation of hair cells within the inner ear

what is tinnitus associated with

presbycusis, Meniere disease, otosclerosis, chronic otitis, labyrinthitis, and other disorders

vertigo

sensation of irregular or whirling motion either of oneself or of external objects

benign paroxysmal positional vertigo (BPPV)

repeated, brief episodes of vertigo, occuring after movement changes in the head

what does paroxysmal mean

sudden onset with a short duration

what is otoconia

calcium crystals

Epley maneuver

series of head movements to relieve symptoms of BPPV

audiometry

testing the sense of hearing

cochlear implant procedure

the surgical insertion of a device that allows sensorineural hearing-impaired people to understand speech

ear thermometry

the measurement of the temperature of the tympanic membrane by detection of infrared radiation from the eardrum

otoscopy

visual examination of the ear canal with an otoscope

tuning fork test

a test of ear conduction using a vibration source (tuning fork)

Rinne test (tuning fork test)

examiner places base of vibrating fork against patient’s mastoid bone and in front of the auditory meatus

Weber test (tuning fork test)

the tuning fork is placed on the center of the forehead and the perceived loudness of sound is the same in both ears if hearing is normal

AD

right ear

auris dextra (L)

right ear

AOM

acute otitis media