Exercise 25: Hearing and Equilibrium Flashcards
Anatomical structures of the external ear
Pinna Lobule External auditory canal Ceruminous glands Tympanic membrane
Anatomical structures of the middle ear
Malleus Incus Stapes Oval window Auditory tube (pharyngotympanic)
Anatomical Structures of the inner ear
Cochlea
Vestibule
Semicircular canals
Pinna
Description: elastic cartilage covered with skin, “antenna”
Function: collects and directs sound waves into the external acoustic meatus
Lobule
Earlobe
External acoustic meatus
Description: short, curved tube filled with ceruminous glands
Function: transmits sound waves from the auricle to the tympanic membrane
Ceruminous glands
Produce cerumen (earwax)
Tympanic membrane
Description: thin connective tissue membrane that vibrates in response to sound
Function: transfers sound energy to middle ear ossicles
Middle ear
A small air-filled chamber, the tympanic cavity
Malleus
“Hammer”, attached to tympanic membrane
Incus
“Anvil”, articulates with malleus and stapes
Stapes
“Stirrup”, base fits into oval window
Function of the auditory ossicles?
Transmit vibratory motion of eardrum to oval window.
Dampened by tensor tympani and stapedius muscles.
Oval window
Description: membrane covered opening, stapes sits on it
Function: transmits vibrations from stapes to perilymph of scala vestibuli
Auditory tube (pharyngotympanic tube)
Description: connects middle ear to nasopharynx
Function: equalizes the pressure in the middle ear cavity with the external air pressure so that the tympanic membrane can vibrate properly
Tensor tympani and stapedius
Tensor tympani attaches to malleus.
Stapedius attaches to stapes.
Help attenuate the vibrations of the tympanic membrane and ossicles.
Contracts to lower amplitude of vibration and volume.
Contract when you’re speaking so your voice doesn’t seem overly loud to you.
Bony labyrinth
Cavity in temporal bone that includes the semicircular canals, the vestibule, and the cochlea.
Filled with perilymph.
Cochlea
A spiral, conical bony chamber.
Extends from anterior vestibule.
Coils around bony pillar called modiolus.
Contains cochlear duct.
Contains the organ of Corti (hearing receptor).
Scala tympani
Terminates at round window
Contains perilymph
Scala vestibuli
Contains perilymph
Scala media
Contains endolymph
Conduction deafness
Something hampers sound conduction to fluids of inner ear (impacted earwax, perforated eardrum)
Sensorineural deafness
Results from damage to neural structures
Tinnitus
Ringing in the ears without auditory stimuli
Meniere’s Syndrome
Labyrinth disorder that affects the cochlea and semicircular canals, causing vertigo, nausea, and vomitting
Vestibular receptors monitor…
Static equilibrium
Semicircular canals monitor…
Dynamic equlibrium
Uttricular hair cells respond to…
Horizontal movement
Saccular hair cells respond to…
Vertical movement
Static equilibrium
Monitoring process of head position and acceleration in a straight line
Dynamic equilibrium
Monitoring process of rotational acceleration of head
