Auditory System Flashcards
three regions of the ear
- external ear
- middle ear
- inner ear
components of the external ear
- auricle
- external auditory meatus
- tympanic membrane
auricle
- S-shaped tube
- outer 2/3 is made of elastic cartilage
- inner 1/3 is made of bone
external auditory meatus location
-opening in temporal bone
external auditory meatus components
- hairs and glands
- cerumen
hairs and glands location/function
- on outer portion of sebaceous glands
- produces oil to lubricate hair and collect dust
cerumen
- aka ear wax
- waxy substance secreted by glands in outer ear
- repels insects
tympanic membrane**
- aka eardrum
- separates the outer ear from middle ear
- very thin membrane
- vibrates when hit by sound waves
middle ear components
- tympanic cavity
- auditory (eustachian tube)
- ossicles (small bones)
tympanic cavity
-lined with mucous cells
eustachian tube**
-connects nasopharynx with middle ear
ossicles components
- malleus
- incus
- stapes
malleus
-attached to tympanic membrane
incus
-interposed between malleus and stapes
stapes
-inserted into oval window of inner ear
inner ear function
-has receptors for hearing and equilibrium
which cranial nerve transmits the receptor impulses to the brain for interpretation?
-vestibulocochlear nerve
what is the inner ear also called?
-labrynth
inner ear inner membranous cavity and tube fluid components
- perilymph
- endolymph
perilymph
-surrounding water
endolymph
-inner water
inner ear components
- cochlea
- vestibule
- semicircular canals
cochlea structure
- spiraling chamber in body labyrinth (“snail”)
- used for hearing
cochlea components
-organ of corti
organ of corti
- located in inner ear
- “hair cell” receptors for hearing
auditory pathway
-cochlear division of CN VIII–> nucleus of CN VIII in medulla–> thalamus–> auditory cortex of temporal lobe (area 41,42)
vestibular apparatus components
- semicircular canals
- utricle and saccule
semicircular canals
- three horse shoe shaped structures arranged at different angles filled w fluid
- motion of head moves hair cells, creating electrical impulse conducted to brain
- important for dynamic equilibrium(i.e. spinning)
utricle and saccule
- bulging chambers in vestibule containing fluid and hair cells w suspended crystals (aka otolins)
- motion causes crystals to move the hair cells, creating electrical impulse
- important for static equilibrium(activated in acceleration; i.e. car, elevator)
vestibular pathway
-vestibular division of CN VIII–> vestibular nuclei of pons and medulla–> cerebral cortex
