Chapter17 part 7 p.590-2 anatomy of ear Flashcards
equilibrium sensation inform of position of head in space by monitoring what 3 things
gravity, linear acceleration, rotation
internal ear is located in petrous part of the _________ bone of the skull
temporal
What is the basic receptors for hearing and equilibrium
hair cells
3 anatomical regions of ear
external, middle, internal
outer fleshy cartilaginous region
auricle/pinna
passageway that pinna surrounds
external acoustic meatus/auditory canal
external acoustic meatus ends at
tympanic membrane/eardrum
glands found in external ear + their secretion
ceruminous glands secrete cerumen
middle ear also called
tympanic cavity
What does the middle ear communicate w/ and through what?
nasopharynx- auditory tube/pharyngotympanic tube/Eustachian tube
mastoid air cells-small connection
describe 2 portions of auditory tube+ its function
- narrow, near connection to middle ear- supported by elastic cartilage
- near opening to nasopharynx- broad and funnel shaped
equalize pressure on either side of tympanic membrane
microorganism invasion through auditory tube
otitis media
middle ear bones (collectively and individual)+ function
auditory ossicles- connect tympanic membrane w/ receptor complex of internal ear
malleus, incus, stapes
malleus function
hammer- attach at 3 points to interior surface of tympanic membrane
incus function
anvil0 middle - attach malleus to stapes
stapes function
edge of base of tapes bound to edge of oval window
oval window
oepning in tempora bone that surrounds internal ear
joints between auditory ossicles
synovial joints
How are sounds amplified?
ossicles act as lever system
tympanic membrane is 22 times larger and heavier than oval window
2 muscles that protect tympanic membrane and ossicles from violent movement
- tensor tympani
2. stapedius
tensor tympani inserts on
handle of malleus
contraction of tensor tympani has what kind of effect?
pulls malleus medially + stiffen tympanic membrane
tensor tympani innervated by motor fibers of mandibular branch of what nerve
trigeminal nerve V
stapedius muscle innervated by what nerve?
facial nerve VII
tensor tympani originates where
petrous part of temporal bond and auditory tube
stapedius muslce originates where
posterior wall of middle ear
stapedius inserts where?
stapes
contraction of stapedius does what?
pulls stapes + reduce mvmt of stapes at oval window
superificial contours of internal ear formed by layer of dense bone known as
bondy labyrinth
walls of bony labyrinth continuous w/ what
surrounding temporal bone
delicate interconnected network of fluid filled tubes inside the bony labyrinth
membranous labyrinth
where are the receptors of the internal ear found?
membranous labyrinth
between the bony and membranous labyrinth flows what
perilymph
what is perilymph
liquid that closely resembles cerebrospinal fluid
membranous labyrinth contains
endolymph
what is endolyph
fluid w/ electrolyte concentrations that differ from those of typical body fluids
3 subdivision of bony labyrinth
- vestibule
- semicircular canals
- cochlea
what is vestibule + name the sacs
pair of membranous sacs- saccule, utricle
function of vestibule
sensation of gravity and linear acceleration
semicircular canals enclose slender________
semicircular ducts
receptors in semicircular ducts stimulated by
rotation of head
vestibular complex
combination of vestibule and semicircular canals
define cochlea
spiral-shpaed, bony chamber
cochlea contains _____ of membranous labyrinth
cochlear duct
where is the cochlear duct located?
sandwiched between pair of perilymph- filled chambers
2 small areas where the wall of the bony labyrinth is not dense bone- describe them
round window- thin, membranous partition that separates perilymph of the cochlear chambers from air- filled middle ear.
oval window- collagen fiber cnnect bony margins of this opening to base of the stapes
