7. middle and inner ear (workbook) Flashcards
what is the middle ear also known as?
tympanic cavity
what does the middle ear contain?
3 ossicles that transmit vibrations from the tympanic membrane to the inner ear in the petrous temporal bone
anteriorly, what does the middle ear communicate with?
nasopharynx via the pharyngotympanic (eustachian) tube
what is the nasopharynx part of?
upper respiratory tract - therefore potential route for infection to spread into middle ear
posteriorly, what does the middle ear communicate with?
mastoid air cells
why is it important that the middle ear communicates with pharyngotympanic tube (eustachian)?
allows equalisation of air pressure between the middle ear and the atmosphere
why is equalisation of air pressure between the middle ear and the atmosphere important?
allow for transfer of sound energy to the internal ear
what is the normal state of the pharyngotympanic (eustachian) tube?
usually closed, being intermittently opened by the pull of attached palate muscles when swallowing
what lies in the upper part of the tympanic cavity?
the ossicles (malleus, incus, stapes)
what is attached to the tympanic membrane from the middle ear?
handle of malleus
what does the body of malleus articulate with?
incus
what does the incus articulate with?
stapes
what is the articulation between ossicles?
synovial joint
serve to relay vibrations encountered by the tympanic membrane to the inner ear
what does the stapes articulate with?
bony labyrinth of the internal ear at the OVAL WINDOW
what is an important anatomical relation of the middle ear?
the facial nerve
where does the facial nerve lie? (within the middle ear)
within the facial canal
what separates the facial nerve from the middle ear cavity?
thin bony partition
what can middle ear infection lead to?
lesion of the facial nerve
what is the inner ear also known as?
the labyrinth
what does the labyrinth (inner ear) consist of?
a series of channels hollowed out of the petrous temporal bone (bony labyrinth) surrounding the membranous labyrinth
what does the membranous labyrinth contain?
fluid called endolymph
what does the membranous labyrinth contain?
fluid called endolymph
what separates the bony and membranous labyrinth?
perilymph fluid
what does the cochlea contain?
cochlea duct - hearing
what does the cochlea contain?
cochlea duct - hearing
what do the semicircular canals communicate with?
the vestibule (balance) and are perpendicular to each other
what does the cochlear duct accommodate?
the spiral organ of Corti
what does the spiral organ of Corti contain?
the receptors of the auditory apparatus (hearing)
what do the utricle and saccule contain?
receptors that respond to ROTATIONAL acceleration and the static pull of GRAVITY
what do the utricle and saccule contain?
receptors that respond to rotational acceleration and the static pull of gravity
what disease can affect the vestibular and cochlear components of the inner ear?
diseases e.g. Meniere’s disease
what are symptoms of Meniere’s disease?
vertigo (room spinning)
hearing loss,
tinnitus (dizziness),
feeling of pressure / fullness in the ear
