HEARING part I Flashcards
the ability to perceive sounds
HEARING
2 fundamental units of the ear
- auditory apparatus - for hearing
- vestibular apparatus - for balance
the ear is divided in 3 main regions:
- external
- middle
- internal
which collects sound waves and
channels them inward
external ear
which conveys sound vibrations to the oval
window
middle ear
which houses the receptors for hearing and equilibrium
internal ear
parts of external ear
- auricle/pinna
- external auditory meatus/canal
- tympanic membrane/eardrum
- Is a flap of elastic cartilage shaped like the flared end of a trumpet and covered by skin
AURICLE/PINNA
- upper portion of auricle/pinna
RIM (HELIX)
- inferior portion of auricle/pinna
LOBULE
- is a curved tube about 2.5 - 3 cm (1 in.)
long that lies in the temporal bone and leads to the eardrum
external auditory meatus/canal
the external auditory canal contains a
few hairs and specialized sweat glands called
ceruminous glands
ceruminous gland secrete
earwax/cerumen
- is a thin semi-transparent membrane that
separates the external ear from the middle ear
tympanic membrane/eardrum
what is the primary function of eardrum
directs sound waves to the middle ear
A small, air-filled cavity that lies in the temporal bone
Separated from the external ear by the tympanic membrane or eardrum & from the
internal ear by a thin bony partition
middle ear (tympanic cavity)
tympanic cavity contains 2 membrane-covered openings called
- oval
- round window
parts of the middle ear
- auditory/eustachian tube (pharyngotympanic tube)
- auditory ossicles (malleus, incus, stapes)
Connects the middle ear to the nasopharynx
auditory/eustachian tube
primary function of auditory tube
equalizes air pressure on both sides of the tympanic
membrane
It Includes the 3 smallest bones of the body and named after their shapes. It is connected by synovial joints
auditory ossicles
primary function of auditory ossicles
transmit sound waves from the eardrum to the fluid in the cochlea thru the oval window
– its handle is attached to the internal surface of the
tympanic membrane and its head articulates with the body of the incus
malleus/hammer
what shape is the malleus
hammer
middle bone; articulates with the head of the stapes
incus/anvil
what is the shape of incus
anvil
its base or footplate fits into the oval window
stapes/stirrups
what is the shape of stapes
stirrups
other term for inner ear
labyrinth
2 main divisions of inner ear/labyrinth
- outer bony labyrinth
- inner membranous labyrinth
- is a series of cavities in the petrous portion of the temporal bone
outer bony labyrinth
outer bony labyrinth is divided in 3 areas:
- semicircular canals
- vestibule
- cochlea
the outer bony labyrinth is lined with periosteum and contains fluid called
perilymph
- snail-shaped (FOR HEARING)
- It is a bony spiral canal that resembles the shape of a snail, making 3 complete turns
cochlea
3 compartments of cochlea
- scala vestibule
- scala tympani
- scala media/cochlear duct
- the upper passage above the bony
partition and ends at the oval window
scala vestibule
– the lower compartment below the bony
partition; ends at the round window
scala tympani
– lies between the scala
vestibule & scala tympani
scala media/cochlear duct
it separates the cochlear duct from the scala
tympani
basilar membrane
it separates the cochlear duct from the scala
vestibule
vestibular membrane
is an organ of hearing which
consists of epithelial cells, supporting cells and hair cells
organ of corti/spiral organ
receptors for auditory sensation
hair cells
30-100 sterocilia (long, hair-like micorvilli)
hair bundles
