Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download parts of the ear combined act as a transducer
Document related concepts
Transcript
All parts of the ear combined act as a transducer, changing acoustic energy into electrochemical energy! Three parts (some sources add a fourth)! 1." Outer! 2." Middle! 3." Inner! 4." Auditory nerve and pathway! Auricle(pinna) ! ! helix - curled outer margin! ! anthelix - interior border! ! crura anthelicis - bifrication of the anthelic! ! ! triangular fossa - space surrounded by crura anthelicis! concha - entrance to ear canal! ! targus - epithelium-covered cartilage! ! antitargus - across from targus! External Auditory Meatus - outer ear canal! ! !! Tympanic Membrane (ear drum) - boundary between outer and middle ear! ! - extremely thin three-layered sheet of tissue! ! !-outer layer extension of EAM! ! !-inner layer extension of middle ear lining! ! !-middle layer fibrous tissue providing structure! ! umbo - most distal point of attachment to malleus! ! cone of light - taut portion! ! ! pars flaccida - flaccid portion lacking fibrous tissue! anterior malleolar fold! ! posterior malleolar fold! Ossicles! ! malleus! ! incus! ! stapes! Medial wall! ! oval window! ! round window! Anterior wall! ! entrance of Eustachian tube! Muscles! ! ! stapedius! tensor tympani! Malleus (hammer)! ! -largest! ! -point of attachment to tympanic membrane! ! -manubrium! Incus (anvil)! Stapes - (stirrup)! ! -footplate rests on oval window! Both reduce strength of the signal (lower frequency) reaching the cochlea! Stapedius (6 mm long) !! Tensor tympani (25 mm long)! ! origin: embedded in bone of posterior wall of middle ear! ! ! insertion: posterior neck of the stapes! bone) ! ! innervation: stapedial branch of VII (facial)! ! insertion: upper manubrium malli! ! function: rotates stapes posteriorly stiffening middle ear ! innervation: V (trigeminal)! system! origin: cartilaginous part of the Eustachian tube (housed in ! function: pulls malleus antero-medially (reducing range of motion) stiffening ! ! !middle ear! Medial Wall! ! ! ! Oval window- connects to scala vestibuli! !resting point of stapes! Round window- connects to the scala tympani! Anterior wall! ! Entrance to Eustachian tube (pharyngotympanic tube)! Vestibule - entry way to cochlea! Semicircular canals - vestibular system (balance)! ! superior (anterior vertical)! ! posterior (posterior vertical)! ! lateral (horizontal)! Cochlea (hearing)! Scala vestibuli -filled with perilymph! Scala tympani - filled with perilymph! Scala media (cochlear duct) - sensory apparatus for hearing! ! !filled with endolymph! ! ! -Reissner#s membrane! -Basilar membrane! ! -Organ of Corti! ! !-inner and outer hair cells! ! !-Tunnel of Corti!
