Ear Flashcards
The ear is what type of organ?
vestibulocochlear organs
what are two main functions of the ear?
- hearing
2. equilibration
Equilibration function of the ear comprises of what 3 aspects?
- balance
- sense of position
- sense of acceleration or deceleration
what are 3 portions of the ear?
- external ear
- middle ear
- inner ear
what does the external ear consist of? (3 parts)
- auricle
- external acoustic meatus
- canal
where does the external ear end?
tympanic membrane or eardrum
what are auricles?
cartilaginous skeleton
what are other names of external acoustic meatus?
external auditory meatus or canal
what does external acoustic meatus has? (2 parts)
- external cartilaginous part
2. inner bony part
what are the helix of the auricles?
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what are the tragus?
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how is the cartilaginous part of the external meatus angled?
- angled downwards
- sightly curved
- concave forwards
what to do with the auricle when examining the tympanic membrane?
gently pull the auricle upwards and backwards
what are the external meatus lined by?
skin continuous with the auricle
what are in cartilaginous part of the external acoustic meatus?
- hair follicles
2. sebaceous glands(along with other glands called ceruminous glands)
what are sensory innervation of the external meatus?
- auriculo-temporal nerve from the trigeminal ,cranial nerve V) 耳廓神经
- cervical nerve plexus颈神经丛
what are sensory innervation of a large part of the auricle?
- auriculo-temporal nerve from the trigeminal ,cranial nerve V) 耳廓神经
- cervical nerve plexus颈神经丛
what are also believed to sensory supply part of the lining of the canal?
vagus
irritation of part of the canal lining cause?
nausea, bradycardia, coughing, and other unpleasant systemic effects
what are middle ear also called?
tympanic cavity
what are in tympanic cavity?
air space with three tiny bones( auditory ossicles)
where are auditory ossicles located?
middle ear/tympanic cavity
what are functions of ossicles?
conduct sound from the tympanic membranes to the inner ear
what does tympanic membrane( 1cm in diameter) separate?
separates the external meatus from the tympanic cavity
what are different coverings of the 2 layers of the tympanic membranes?
- outer surface: epidermis
2. inner membrane: mucous membrane
what is layer between 2 epithelial tympanic membranes?
a thin fibrous layer
how is the tympanic membrane when seen from the outer aspect?
fairly tense and concave
what is a flaccid or floppy part superior to tympanic membrane called?
handle of the malleus (forming a slightly raised ridge)
what are functions of the tympanic cavity?
conduct sound from the tympanic membrane to the tiny membrane that interfaces with the inner ear
where does the tympanic cavity situated?
within the temporal bone
posterior tympanic cavity communicates with?
mastoid air cells 乳突细胞
mastoid antrum via aditus(opening)
http://chestofbooks.com/health/anatomy/Human-Body-Construction/images/Fig-103-Right-temporal-bone-The-outer-surface-has-bee.jpg
anteriorly tympanic cavity communicates with?
nasopharynx via auditory tube
https://openi.nlm.nih.gov/imgs/512/377/1876255/PMC1876255_431_2007_461_Fig4_HTML.png
what are auditory tubes also called?
pharyngo-tympanic tube
Eustachian tube
auditory tube is divided into two canals?
- one for air
2. one containing muscle: tensor tympani
what muscle help dampens loud sounds in the middle ear?
- tensor tympani (attach to the handle of the malleus)张力鼓掌（附在锤骨的柄上）
- stapedius( dampen the movement of the stapes)
what supply tensor tympani?
trigeminal nerve(V)
what supply stapedius?
facial nerve(VII)
What is the promontory?
medial wall of tympanic cavity formed a bulge
what lies upon the promontory?
tympanic nerve plexus 鼓神经丛
where is oval window situated?
upper part of the media wall of tympanic membrane
what is oval window also called?
fenestra vestibuli
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what are on either side of the oval window?
- base of the stapes
2, fluid of the vestivule of the inner ear
what are corresponding membrane of oval window that can vibrate in the opposite phase?
round window (fenestra cochleae )
what is round window also called?
fenestra cochleae
where is round window situated?
on the medial wall of the tympanic cavity below the oval window
what are vibrations of oval window and round window?
when oval window vibrates inwards, the round window vibrates outwards
what is the roof of the tympanic cavity called?
tegmen tympani
what does tegmen tympani separate?
separates cavity from the middle cranial fossa
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the tympanic cavity floor is directly above ?
jugular foramen and jugular bulb
anteriorly: carotid canal
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what opening in anterior wall of the tympanic cavity?
- opening of the auditory tube
2. carotid canal (lower part of anterior wall)
what main structure in the posterior wall of the tympanic cavity?
facial canal
what does the facial canal do?
transmit the facial nerve just above aditus into the mastoid antrum
what are two branches of the facial nerve?
emerge from the facial canal and enter the tympanic cavity
- upper most nerve to stapedius muscle
2, chorda tympani (sensory of anterior 2/3 of tongue)
what are three ossicles to transmit the vibrations from the tympanic membrane to the oval window?
- malleus (the hammer)
- incus (the anvil)
- stapes (the strirrup)
acoustic connections of the chain of three ossicles?
- handle of the malleus ( connects to tympanic membrane)
2. footplate/base of stapes (connects to oval window) acts as a “tilting plunger”
what are inner ear also called?
vestibulocochlear apparatus
where does inner ear lies?
petrous part of the temporal bone
where is membranous labyrinth?
lodged within bony labyrinth (similar arrangement )
are ducts of the membraneous labyrinth all continuous with each other?
yes
what are relationship of endolymph and perilymph?
perilymph surrounded by endolymph
where is perilymph?
between the ducts and the walls of the bony labyrinth
what is essential organ of hearing?
cochlea
what are other portions of the inner ear other than the cochlea?
saccule, utricle and the semicircular ducts
cochlea VS bony labyrinth?
cochlear is part of the bony labyrinth
cochlear duct VS membranous labyrinth?
bony labyrinth contains the cochlear duct, a part of the membranous labyrinth
describe cochlea?
helical tube
around 2.5 turns
base lying against lateral end of internal acoustic meatus
the bulge of basal coil of the internal acoustic meatus form?
promontory
what is the modiolus of the cochlea?
central supporting core
what is spiral lamina?
a spiral shelf course up towards the apex around the modiolus
what are utricle and saccule?
bony labyrinth contains the utricle and the saccule of the membranous labyrinth
semicircular canals VS bony labyrinth
semicircular canals are part of the bony labyrinth
what are arrangement of three semicircular canals?
at right angles to each other
sensitive to movement of fluid and particles
