Samsam Anatomy Test 5

ear
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Terms in this set (53)
ear
contains 2 sense organs, 3 parts: external, middle, and internal
external ear
includes the auricle and external acoustic meatus
middle ear
includes the tympanic vacuity with the ossicles, mastoid cells, and auditory tube
internal ear
includes bony labyrinth that contains the membranous labyrinth and the interal auditory meatus
external acoustic meatus
2.5cm, first part is cartilage, lined by epidermis and contains ceruminous glands, terminates at tympanic membrane
cerumen glands
wax produced, wax collects insects and dust
CN 7
muscles around the auricle are innervated by
innervation of external ear
auricular branch of CN IX and X
lesions
including infections of the canal may cause nausea or vomiting
sensory afferents of canal
carried by vagus and glossopharyngeal nerves which contain parasympathetic fibers to upper GI tract
gag reflexCN IX; induced by insect entering external auditory meatus or removing cerumenchronic infection of the external earmay lead to bony hyperplasia and narrowing of the meatus (swimmer's ear)otoscope (auriscope)clinical examination of the meatus and the membrane is done by this; supplied by shining light into a hollow speculum, cone of light seen has its apex at Umbo and expands downward and forwardmyringotomyincision through the tympanic membrane (its anteroinferior quadrant) and insertion of a tube for drainage of secretions and pus in severe cases of otitis media and/or chronic otitis mediatympanic cavitytall and narrow spaceborders of middle earlateral, medial wall, vestibular window, cochlear window, roof, floor, anterior, posteriorlateral bordertympanic membranemedial wallhas 2 openings leading to the internal earvestibular windowoval shapecochlear windowround shaperoof bordersegmental wall of petrous bone, between cranial and tympanic cavitiesfloor borderthin bony plate, beneath which passes the jugular veinanterior borderbone, separating the cavity from carotid artery; auditory canal and canal for tensor tympani muscle are seenposterior bordermastoid wall, tympanic or mastoid antrumstapescovers oval window, vibrations go through scala timpani where round window is (2ndary tympanic membrane)annular ligamentconnects stapes to oval window; with a loud sound the stapes muscle pulls stapes out of window so loud sound isn't as loud)hyperacusiscondition when stapes muscles can't function well so patient hears sounds louder than normalmost common cause of adult deafnessannular ligament can calcify around stapesauditory ossiclesthree bonds, that together with the tympanic membrane, transmit the sound across middle ear to the internal ear, malleus, incus, and stapestensor tympani muscleinserted to the handle of the malleus, inverted by V/3; tenses the tympanic membranestapedius muscleinserted neck of stapes; innervated by CN7 the stapedius branch, function; dampens stapesfacial nerves paralysiscauses loss of function of stapedius muscle and loss of dampening the sound stimuli, leading to hyperacusisauditory tubesinfection from nasopharynx can get into the middle ear throughtympanic membranea pressure difference of 100-150mmHg can rupture theinner earcomposed of membranous labyrinth which is covered by very hard bony labyrinth in petrous part of the temporal bonelabyrinthhas a middle part, the vestibule, the cochlea and the semicircular canalsperilymphbony labyrinth, clear aqueous fluid, outside, more sodiumendolymphmembranous labyinth, more potassium, more like intercellular fluidvestibulecontains the membranous saccule and utricle, both carry sensory epithelium the macula sacculi and macula utriculimaculasensory neurons about movementampulladialation in semicircular canalsmacula sacculi and macula utriculiresponsible for detecting accelerationcristi ampullaangular acceleration or turning; hair cells move toward movement and slightly further then return to restingcochleaorgan of corti, containing the hair cells involved in hearingcochlear ductfilled with endolymphscala vestibulilies above the duct, has perilymphscala tympanilies below the duct, has perilymphsensory cellsinner(one layer) and outer hair cells(multiple rows) which has cilaetectorial membranegelatinous layer; displacement of the cilia against it produces the neuronal signalorgan of balancesacculus, utriculus, and 3 semicirculuar ductsvestibulocochlear (CN VIII)sensory nerves, composed of cochlear and vestibular nervescochlear nervesinvolved in hearing, consists of the central axons of bipolar neurons lying in the spiral ganglia in the Cochlea of the inner ear, peripheral processes extend to hair cells and central axons combine to form the cochlear nervesvestibular nervesinvolved in balance, consists of the central axons of vestibular ganglion cells which merge from the base of the internal acoustic meatus. peripheral axons of the ganglion cells come from to ampullary cristae of the semicircular ducts and from macula of trickle and the saccule