clinical anatomy of ear and taste Flashcards
what nerve supplies the portion of the ear highlighted orange?
C2, 3 spinal nerves (via lesser occipital nerve)
what nerve supplies the portion of the ear highlighted yellow?
facial nerve (CNVII)
what nerve supplies the portion of the ear highlighted purple?
greater auricular nerve (C2, C3)
what nerve supplies the portion of the ear highlighted blue?
auricular nerve (via vagus)
what nerve supplies the portion of the ear highlighted green?
auriculotemporal nerve (via CNV3)
what are 1 and 2 ?
1= concha 2= tragus
what is the main function of the tympanic cavity?
-to conduct sound waves in the air towards fluid filled cavities of the inner ear
how does the size of the bones change in the tympanic cavity and why?
-they decrease in size from lateral to medial for amplification
what are the bones of the tympanic cavity?
- stapes
- incus
- malleus
what are a,b and c?
a= malleus
b=incus
c=stapes
what type of joints join together the stapes, incus and malleus and why?
-synovial joints to allow for smooth movement
fill in the blank
oval window
what are the two muscles in the tympanic cavity?
- tensor tympani muscle
- stapedius muscle
where does the tensor tympani muscle run from?
it runs from the cartilaginous portion of the eustachian tube to the handle of the malleus
what is the role of the tensor tympani muscle?
-it dampens sound by reducing vibrations of the tympanic membrane
what innervates the tensor tympani muscle and why?
CNV3 (mandibular)
-reduces sound of chewing
where does the stapedius muscle run from?
-the pyramidal eminence to neck of stapes
what is the role of the stapedius muscle?
-it dampens sound by reducing the vibrations of stapes on oval window
what nerve innervates the stapedius muscle?
CN VII (Facial)
what occurs in the eustachian tube to equalise pressure?
-the palate muscles open
where is the eustachian tube located?
it runs from the anterior wall of the middle ear cavity to nasopharynx
what is otitis media?
-middle ear inflammation
why can tonsillitis or pharyngitis mimic otalgia (earache)?
as they are all supplied by CN IX (the glossopharyngeal nerve)
what are most of the nasopharynx and oropharynx supplied by for sensory?
CN IX (glossopharyngeal)
what is most of the laryngopharynx sensory supplied by?
CN X (vagus nerve)
what can mastoiditis lead to?
osteomyelitis
how may the tympanic cavity be accessed during surgery?
-through the mastoid
where is the mastoid antrum located in relation to the tympanic cavity?
-it is continuous with the tympanic cavity
what is the mastoid antrum lined with?
mucosa
where is the otic capsule located?
-in the temporal bone
what is the otic capsule like compared to the temporal bone (in terms of density)?
otic capsule is denser
how developed is the otic capsule at birth?
fully developed
what are the two labyrinths contained within the otic capsule?
- bony labyrinth
- membranous labyrinth
what is the bony labyrinth?
-a cavity of the otic capsule
what is the membranous labyrinth?
a labyrinth suspended within the bony labyrinth
what type of lymph is the bony labyrinth filled with?
perilymph which is similar to extracellular fluid
what type of lymph is found within the membranous labyrinth?
endolymph which is similar to intracellular fluid
how does hearing work?
- sound waves make the tympanic membrane vibrate
- vibrations are transmitted through ossicles
- footplate of stapes vibrate in oval window
- vibration of stapes creates pressure waves in perilymph
- hair cells in the cochlea are moves, action potentials are stimulated and conveyed to the brain by cochlear nerve
- pressure waves descend and become vibrations again
- pressure waves are dampened at the round window
what suspends the cochlear duct?
spiral ligament
what is the cochlear apparatus divided into?
- scala vestibuli
- cochlear duct
- scala tympani
what is affected in conductive hearing loss?
- external ear
- middle ear
what is affected in sensorineural hearing loss?
-inner ear
what is responsible for balance and perception of head movement in the ear?
-vestibular apparatus
what parts of the vestibular apparatus detect angular movement change?
-semicircular movement change
what parts of the vestibular apparatus detect linear movement change?
utrcile= horizontal Saccule= vertical
what innervates the posterior 1/3 of the tongue (vertical part) and what innervates the anterior 2/3 of the tongue (horizontal part)?
posterior 1/3 (horizontal part)= glossopharyngeal CNIX for taste and general sensory
anterior 2/3 (vertical part)= general sensory is mandibular part of trigeminal nerve CNV3 and taste is CN VII facial nerve
