Exam 5, week 8 review

Peripheral Auditory System - outer, middle, and inner ear. collect sound waves and transform waves to electro and mechanical energy before it goes to the brain for interpretation.

Central Auditory System - brainstem, and auditory cortex. the brain interprets what the ear has heard

Auricle/Pinna - outer ear, what you see (the ear). Helps to localize, gather, and direct sound. filled with pits and grooves.

Aplasia - a condition where the ear canal does not develop, or doesn’t develop completely

Microtia - a birth defect where the outer ear (pinna) is small and/or not formed correctly

External Auditory Meatus - ear canal, outer 3rd of the canal lined with cilia, has glands to produce cerumen (earwax)

Cilia - hair-like structures that are crucial for healing, balance, and clearing cerumen. damage to the cilia can cause hearing loss, and can be done by excessive loud noise, aging, oxygen deprivation

Cerumen - earwax

Middle Ear Cavity - transmits sound vibrations from the eardrum to the inner ear, and equalizes air pressure.

Tegmental Wall - roof of the middle ear cavity, paper thin, seperates middle ear, from the dura matter 

Tympanic Plate - curved bony plate that is part of the temporal bone.  makes up or forms the floor on the middle ear cavity 

Oval Window - space/hole that recieves vibrations from the footplate of the stapes as it moves up and down in the window

Round Window - has a thin membrane across, containing fluid in the cochlea.  serves as pressure release for the fluid inside the cochlea.  as the oval window vibrates, the round window bulges inward to allow fluid inside cochlea to move, enabling the continous vibration needed to generate nerve signals for hearing.  

Promontory - bulge or protrusion between the windows 

Pyramidal Eminence - houses the stapedius muscle, and contains a small opening that transmits the nerve to the stapedius muscle from the facial nerve 

Tympanic Membrane - thin tough layers that vibrate easily to recieve sound eaves, and transmits them to the middle ear. vibrates, and amplifies sound. Malleus is directly connected by the manubrium. Completely serperates Outer and Inner ear

Tympanic Membrane Layers - 1. outer cuticular layer 2. intermediate fibrous layer a. superficial layer of fibers that radiate out from center b.deep layer of circular fibers 3. inner mucous layer

Tympanic Sulcus - indentation on the temporal bone, where the tympanic membrane fits in 

Auditory Ossicles/Middle Ear Bones - Ossicular Chain. Malleus, Incus, Stapes. smallest bones in the body. function: transmit acoustic mechanical energy (sound waves) from tympanic membrane to the inner ear. function: keep the inner ear from being hurt by excessive vibration, they will stiffen when noise is too loud.

Stapedius Muscle - innervated by cranial nerve 7 (facial), Inserts into head/neck of stapes. Functions to rotate the stapes posteriorly

Tensor Tympani Muscle - innervated by cranial nerve 5 (trigeminal), Inserts on the upper manubrium or anterior process of malleus, functions to pull the malleus anteriorly and medially

Acoustic Reflex - triggered by loud sounds, stapedius contracts → stiffens the ossicular chain → reduce sound intensity and protect the inner ear

Eustachian Tube (auditory Tube) - functions to establish communication between middle ear and nasopharynx.  children’s eustachian tubes are shorter and more horizontal, and this can cause ear infections because it is easier for bacteria from colds to travel to the tube

Osseous Labyrinth - inside the petrous portion of the temporal bone, consists of cochlea, vestibule, and semicicrular canals.  Filled with perilymph. function: provides support and protection for the membranous labyrinth 

Membranous Labyrinth - delicate sac-like structures located within the bony labyrinth.  consists of cochlear duct, saccule and utricle, and semicircular ducts.  Filled with endolymph.  Function: contains sensory receptors for hearing and balance 

Petrous Portion - dense, pyramid portion of the skull located between the sphenoid and occipital bones that house the inner ear structures for hearing and balance. 

Vestibule - central chamber of bony labyrinth.  houses 2 sacs - utricle + saccule which are part of the balance system.  these sacs contain sensory receptors that detest linear acceleration and position of the head 

Semicircular Canals - 3 bony canals, they contain the 3 semicircular ducts of membranous labyrinth.  responsible for detecting rotational movement of the head 

Cochlea - organ of hearing, spiral shaped cavity, contains cochlear duct that houses organ of corti-the sensory organ for hearing

Semi-circular ducts - fluid filled tubes in the inner ear that detect rotational movement of the head to help maintain balance.  part of the vestibular system.   anterior(superior) rotate side to side (shaking head no), lateral (nodding head up and down), posterior (tilt head side to side).

Ampulla - bulb-shaped enlargement at the base of each semicircular canal in the inner ear.  responsible for maintaining balance, and spatial orientation.  contains crista ampullaris (sensory organ lined with hair cells)

Tonotopic - describes the tonotopic organization of the inner ear, a principle where the inner ear’s cochlea is mapped to sound frequencies.  High frequency sounds are processed at the base of the ear (narrow, more tense).  Lower frequency sounds are processed at the apex (wider, more flaccid)

Modiolus - central pillar of bone that the cochlea coils around 

Internal Auditory Meatus - superior portion contains facial nerve, and superior vestibule nerve.  inferior portion contains cochlear nerve and inferior vestibular nerve.  functions to transmit cranial nerve 8, which carries sensory info for hearing and balance.  Damage can cause hearing loss, vertigo

Perilymph - fluid in the bony cochlea, contains membranous cochlea, 

Endolymph - fluid inside membranous cochlea 

Cochlear Duct - convert sound vibrations into electrical signals that the brain can interpret as sound, houses the organ of corti 

Static System - functions to percieve position in space, knowing hwere gravity is, position of the head, if it is straight or tilted 

Kinetic System - perception of rotation and exelleration of the head

Endolymphatic Duct - narrow, fluid filled tube located in the inner ear.  connects the endolymphatic sac to the membranous labyrinth. maintains fluid balance, and pressure within the membranous labyrinth 

Crista Ampularis - highly developed sensory cell, sense acceleration and deceleration through hair cells embedded in a gelatinous structure called the cupula 

Cupula - gelatin-like mass, cilia embedded in it, floating in an endolymph fluid, detects movement and motion for balance 

Occulomotor nerve - controls eye movement, controls the pupil and lens of the eye 

Vertigo - the sensation of spinning and/or whirling 

Nystagmus - the rapid rocking movement of the eyes.  

Motion Sickness - causes by a mismatch between tour eyes and vestibular system

Angular Accelerations - detected by the semicircular canals, part of the vestibular system 

Basilar Membrane - membrane in the cochlea that bears/supports the organ of corti.  narrow and more tense at the base, and becomes wider and more flaccid as it coils 

Vestibular Membrane - thin membrane in the cochlea of the inner ear that seperates the scala vestibuli and the scala media.  acts as a barrier between different fluid fille chambers 

Reissners Membrane - acts as a barrier and assists in diffusion of endolymph and perilymph, to maintain their distinct ion concentrations

Helicotrema - small opening at apex of cochlea where the scala vestibuli and scala tympani connect.  connection allows pressure changes from the oval window to be transmitted through the inner ear fluid and eventually reach the round window causing the basilar membrane to vibrate 

Organ of Corti - sensory structure, converts sound vibrations into electrical signals that are transmitted to the brain for interpretation.  also called spiral organ (of corti)

Supportive Cells - function not entirely clear, 4 types, phalangeal, rods of corti, ells of deiters, supporting cells of hensen, 

Receptor Cells (sensory) - inner and outer hair cells 

Tiplinks - between stereocilia, coiled fibrals that join the stereocilia, when just 1 stereocilia is bent/moved, the tiplinks will cause the rest to fall in motion and do the same 

Stereocilia - hair-like projections on inner hair cells that assist with converting mechanical motion into electrical signals, for the brain to process.  the bending of these causes ion channels to open at the tips of the cilia, then glutimate is released to the neuron axons of the auditory nerve 

Impedance - resistance to the flow of energy; water has more impedance than air, you don’t want to decrease/lose the flow of energy

Otitis Media - inflammation of the middle ear cavity.  lose some of the impedance matching functions causing loss of decibels (volume)

Spectral Analysis - the process of extracting or defining the various frequency and intensity components of a given sound 

Traveling Wave - the vibration that is transmitted to the basilar membrane

Psalm 139 13-16 - For you created my inmost being you knit me together in my mother’s womb. I praise you because I am fearfully and wonderfully made; your works are wonderful; I know that full well.   My frame was not hidden from you when I was made in the secret place, when I was woven together in the depths of the earth.  Your eyes saw my unformed body; all the days ordained for me were written in your book before one of them came to be.

Helix – outer rim of the ear, helps to collect and direct sounds into the external auditory meatus

Antihelix – inner curved ridge parallel to the helix, supports the ear shape

Concha – deep cavity leading to the external auditory meatus, includes both the cave and the cymba, funnels sound toward the tympanic membrane

Cave – lower portion of the concha, directs sound into the ear canal

Cymba – upper portion of the concha, assists in channeling sound

Crus of Helix – ridge where the helix begins above the external auditory meatus, marks the boundary of the concha

Scaphoid Fossa – narrow groove between the helix and antihelix, contributes to ear shape

Tragus – small cartilage flap in front of the external auditory meatus, helps localize sounds from front vs back

Antitragus – small projection opposite the tragus, assists in sound direction

Intertragal Incisure – notch between tragus and antitragus; entry point to external auditory meatus

Lobe – soft lower part of the ear, has no cartilage, assists with blood flow, and balance of the ear shape

Pars Flaccida – small, slack upper portion of the tympanic membrane, helps to equalize pressure

Anterior and Posterior Mallear Folds – ridges formed by the malleus attachment, help to maintain tympanic membrane tension

Pars Tensa -taut lower part of the tympanic membrane, vibrates in response to sound waves

Cone of Light – reflection of light, in the bottom area of the tympanic membrane that you see when doing an ear exam, indicates a healthy tympanic membrane

Malleolar Stria – line seen through the tympanic membrane, shows the attachment of the malleus

Umbo – central point where malleus attaches,

Isthmus –  narrow passage connecting middle and inner ear structures, part of the eustachian tube region

Spiral Lamina – bony shelf extending from modiolus, supports organ of corti

Scala Vestibuli – upper fluid-filled chamber of inner ear, carries sound vibrations from the oval window

Scala Tympani – lower chamber of inner ear, returns vibrations to round window

Scala Media – also called cochlear duct, middle inner ear chamber, contains the organ of corti, filled with endolymph for transduction

Utricle – detects horizontal linear acceleration

Saccule – detects vertical linear acceleration

Phalangeal cells (inner phalangeal cells) – supports inner hair cells

Rods of Corti – form the tunnel of corti, and provide structural support, triangle shaped?

Cells of Deiters (outer phalangeal celles) – support outer hair cells, and anchor them to the basilar membrane

Supporting cells of Hensen – support lateral side of organ of corti, and maintain ionic balance, tall columnar cells

Inner Hair Cells - primary sensory receptors for sound, convert vibrations to neural signals (mechanical to electrical)

Outer Hair Cells – amplify and fine-tune sound vibrations on the basilar membrane

Tectorial Membrane - gel-like structure above the hair cells, contracts stereocilia during sound vibrations

Shearing Action – movement between basilar and tectorial membranes that bends the hair cell stereocilia, triggers receptor potentials

Usher Syndrome – genetic disorder causing combined hearing and vision impairment.  Hellen Keller, the most famous example

Cochlear Nucleus – the first brainstem relay for auditory signals from the cochlea

Superior Olivary Complex – processes sound localization, time and intensity differences

Inferior Colliculus – midbrain center integrating auditory spatial information

Medial Geniculate Body – thalamic relay to auditory cortex, processes complex sound patterns

Auditory Cortex – final area for sound perception, interpretation, and speech understanding