Anatomy 5 Flashcards
auricle sens innerv? blood supply? lymph drain?
skin -> auriculotemp & greater auricular nn; ext ac meatus & outer TM -> auriculotemp & CN10 nn. superficial temp & post auricular aa. (post -> mastoid, ant -> parotid, inf) -> sup cerv -> deep cervical LN
external acoustic meatus = what shape? lat vs med part = ?
s shaped tunnel. cartilage w/ sebaceous & cerumen glands vs bony
TM: pars flaccida vs pars tensa. malleolar stria vs umbo. cone of light
aka shrapnell membrane, small, flaccid vs lg, taut. attaches malleus handle in inner TM vs puckering of TM drawn inward attaching low tip of malleus. triangle light d/t otoscope
know tympanic cavity borders. what does it house?
Lec 41, slides 9-10. ossicles
describe E tube
connects tympanic cavity w/ nasopharynx. sup part = bony, distal part = cartilage. yawn/swallow opens e tube –> equalize mid ear pressure w/ atm pressure
describe nn w/in tympanic cavity?
CN7 in facial canal -> chorda tympani b/w mal/tensor tympani & inc and leaves thru petrotympanic fissure to infratemp fossa; n to stapedius. CN 9 -> tympanic plexus -> promontory -> lesser petrosal n
describe tympanic muscles: tens tympani & stapedius
V3 & 7; stabilize ossicles or else hyperacusis
know inner ear bony & membranous labyrinths. describe cochlea. describe organ of Corti
Lec 41, slide 16. around modiolus; scala vestibuli & tympani both w/ perilymph connecting via helicotrema; membranous cochlear duct w/ endolymph. in/outer hair cells in cochlear duct; perilymph displaces basilar mem -> bend stereocilia in tectorial mem; displaced outer hair cells -> amplify amplitude, displaced inner hair cells (1o sensory receptors) -> AP of afferent cochlear n -> send to CNS as sound
utricle & saccule. know fxn of maculae
parts of mem labyrinth w/in bony vestibule housing maculae detecting gravity pull & linear acc; stereocilia & kinocilium in gelatinous otolithic mem; otolith mem capped by CaCO3 crystals (otoconia) detecting gravity & linear acc. head tilt -> otoliths drag otolith mem in direction of gravity. Lec 41, slide 25
sens pathways for inner ear
corti -> spiral ganglia -> coch n -> CN8 -> hearing
macula -> vestib ganglia -> vestib n -> CN8 -> gravity & lin acc
crista ampullaris -> vestib ganglia -> vestib n -> CN8 -> rot/angular acc
cryptotia vs polyotia vs preauricular sinus vs microtia vs stahl’s bar vs prominent ears
upper pole = buried under temporal skin vs persistent preauricular tissue included in pinna vs incomplete fusion of 1/2nd pharyngeal arches vs diminutive ear, from FAS or thalidomide vs flat helix, duplicated upper crus antihelix vs absent/incomplete antihelical fold
what’s otosclerosis?
tissue overgrowth -> stapes fixed to oval window
transduction pathway
stereocilia on tect mem -> K+ channels open -> influx K+ -> depol -> influx Ca2+ -> synaptic vesicles fuse w/ plasma mem -> NT released to aff periph n
describe basilar membrane. freq for human hearing & speech?
narrow/stiff at base, wide/flexible at apex; low freq/taller cilia travel to apex, high freq/shorter cilia travel to base. 20-20000Hz, 100-8000Hz
mid ear reflex
stapedius/CN7 LMN caudal to sup olivary complex; tensor tympani/V3 motor nucleus rostral to sup olivary complex -> cochl n gives aff info -> reflex = bil to protect inner ear from loud sounds