The Ear Flashcards
Bony labyrinth
Inner ear network of cavities
Bony labyrinth divisions
Cochlea
Central vestibule
3 semicircular cnal
All cavities of bony labrynth contain
Perilymph fluid
Perilymph fluid
High Na, low K
In bondy labyrinth
Inner ear found
In petrous ridfe of temporal boine
Membranous labyrnth surrounded by
Bony
Membranous labyrinth filled with ____ and concentration
Endolympth (low Na, High K)
Membranous labyrinth divides _______ into _______
Bony vestibule into utricle and saccule
Utricle and saccule contain
Maculae (sensory organs)
Cristae ampularis
Sensory organs of the semicircular canals
Auricle function
Connect pressure waves and funnel into external acoustic meatus
Sound waves cause________
Tympanic membrane to vibrate
Parts of extenral ear
Pinna
External acoustic meatus
External tympanic membrane
Tympanic membrane concavity
Toward external acoustic meatus
Umbo
Center of depression of membrane…reflects bright lights
Which bone fuses to tympanic membrane
Malleus
Pars tensa of tym memb
Larger protion below malleolar fold
Pars flaccida of tym memb
Small part above malleolar fold
Chorda tympani runs in middle ear deep to
Pars flaccida of tym mem
Middle ear
Air filled cavity deep to tymp membrane
Middle ear contents
Ossicles
Stepdius and tensor tymp msucles
Chorda tympani nerve
Tymp plexus of nerves
Tympanic cavity proper
Middle ear space directly behind tympanic membrane
Epitympanic recess
Middle ear space superior and behind
Lateral wall of middle ear
Tympanic membrane
Medial wall of membrane
Prom of coch
Oval/round window
Tym plexus
Prom of facial canal
Tympanic plexus
Tympanic nerve (from CN 9) divides into branches…Innervate mucosa of middle ear..also produces lesser petrosal that provide autonomics to parotid
Ossicles transmit sounds
From air to cochlea
Malleus attaches to
Tym mem
Incus articulate with
Malleus in the epitympanic recess
Stapes articulates
With incus and fuses to oval window covering entrance to inner ear
Roof of middle ear
Tegmen tympani - thin bone separating middle ear from middle cranial fossa
Floor of middle ear
THin bone separating middle ear cavity from IJV
Epitympanic recess communicates with _____ posteriorly
Mastoid air cells
Stapedius function and innervation
CN 7
Dampens movement of loud sounds
Chorda tympani passes
Lateral wall between malleus and incus…exits via petrotympanic fissure into IT fossa
Auditory tube
How middle ear communicates anteriorly with nasopharynx
Tensor tympani passes with, function, innervation
Pharyngeotympanic tube from anterior to insert on malleus
Dampens malleus during loud sounds
V3 of CN 5
Modiolus
Central bony core of labyrinth
Supports spiral ganglion of CN 8
Spiral lamina
Projects from modiolis and divides bony cochlea
Base of cochlea
Closest to oval windowq
Apex of cochlea
At top of spiraled cochlea
What forms cochlear duct
Vestibular (roof) and basilar membrane (floor)
Cochlear duct is
CLosed sac that spirals up the cochlea but doesn’t reach the end
Cochlear duct filled with
Endolymph
Sacala vesibuli
Duct above vestibular membrane
Scala vestibuli continuous with
Sacala tympani that lies below basilar membrane
3 ducts of inner ear orinetation
Parallel
Organ of corti
Auditory sensory organ
Basilar membrane supports
Organ of corti
Organ of corti composed of
Hair cells and supporting cells
How is cranial nerve 8 depolarized
Movement of hair cells
Stapes transmits sounds into
Sacala vestibuli
How does sound wave escape cochlea?
Round window
Basilar membrane resonance
Differences in width and thickness allow for specific frequencies
Locations of frequences of basilar membrane
CLose to base - higher frequency and thicker
Basilar membrane organizes sound into a
Topographic place code along length called a tonotopic map
Path of tympanic nerve
Runs to tympanic plexus, becomes lesser petrosal, through hiatus, through foramen ovale to IT fossa, synapse in otic ganglion, run to parotid gland with auriculotemporal nerve
