ANATOMY AND PHYSIOLOGY OF THE EAR 1 Main Components of the Hearing Mechanism Outer Ear Middle Ear Inner Ear
Central Auditory Nervous System 2 Structures of the Outer Ear Auricle (Pinna) Collects sound Helps in sound localization
Most efficient in directing high frequency sounds to the eardrum 3 External Auditory Canal
Approximately 1 inch in length S shaped Lined with cerumen glands Outer 1/3rd cartilage; inner 2/3rds mastoid bone Increases sound pressure at the tympanic membrane by as much as 5-6 dB (due to acoustic resonance) 4 Mastoid Process
Bony ridge behind the auricle Provides support to the external ear and posterior wall of the middle ear cavity 5 Tympanic Membrane
Thin membrane Forms boundary between outer and middle ear Vibrates in response to sound Changes acoustical energy into mechanical energy 6
The Ossicular Chain A: Malleus B: Incus C: Stapes Ossicles are smallest bones in the body
Act as a lever system Footplate of stapes enters oval window of the cochlea 7 Eustachian Tube
Lined with mucous membrane; connects middle ear to back of the throat (nasopharynx) Equalizes air pressure Normally closed except during yawning or swallowing Not a part of the hearing process 8 Stapedius Muscle
Connects the stapes to the middle ear wall Contracts in response to loud sounds; known as the Acoustic Reflex 9 Structures of the Inner Ear Cochlea - Snail-shaped organ with a series of fluidfilled tunnels; converts mechanical energy into electrical energy
10 Structures of the Inner Ear (Cont.) Oval Window located at the footplate of the stapes; when the footplate vibrates, the cochlear fluid is set into motion Round Window functions as the pressure relief port for the fluid set into motion initially by the movement of the stapes in
the oval window 11 Organ of Corti The end organ of hearing; contains stereocilia and hair cells. 12 Hair Cells
Frequency-specific High pitch sounds = base of cochlea Low pitch sounds = apex of cochlea When the basilar membrane moves, a shearing action between the tectorial membrane and the organ of Corti causes hair cells to bend 13
Vestibular System Consists of three semicircular canals Shares fluid with the cochlea Controls balance No part in hearing process 14
Central Auditory System 8th Cranial Nerve or Auditory Nerve carries signals from cochlea to brain Fibers of the auditory nerve are present in the hair cells of the inner ear Auditory Cortex: Temporal lobe of the brain where sound is perceived and analyzed
15 How Sound Travels Through The Ear... Acoustic energy, in the form of sound waves, is channeled into the ear canal by the pinna. Sound waves strike the tympanic membrane, causing it to vibrate like a drum, and changing it into mechanical energy. The malleus, which is attached to the tympanic membrane, starts the ossicles into motion. (The middle ear components mechanically amplify sound). The stapes moves in and out of the oval window of the cochlea creating a fluid motion. The fluid movement within the cochlea causes membranes in the Organ of Corti to shear against the hair cells. This creates an electrical signal which
is sent via the Auditory Nerve to the brain, where sound is interpreted! 16 QUESTIONS? 17
Meiosis Practice Test. ... How does the genetic content of cells resulting from meiosis and mitosis differ? Mitosis they are different. ... Quiz Friday on meiosis. Meiosis packet due friday. Test corrections. SEPARATE SHEET OF PAPER!!! Question #
If have a curved surface (wave front) and the bottom of the surface moves slower than the top the surface will have a torque on it which will tend to turn the curved surface towards the slow speed area. ......
Interprocess Communication CSE 380 Lecture Note 8 Insup Lee Interprocess communication Shared Memory Message Passing Signals Shard Memory Shared Memory in Solaris Processes can share the same segment of memory directly when it is mapped into the address space of...
Apurva Joshi (AJ) Senior Program Manager. When Bad Things Happen to Good Apps: Troubleshooting Application on Azure App Service. ... Application Issues. Impacts . specific. customer SLA (Hey, Man) Generic FAQ. No SLA impact (OMG!!!) Platform Issue. Impacts . multiple.
Market Structures for U.S. Water Quality Trading Richard T. Woodward & Ronald A. Kaiser Texas A&M University Pollution trading is on the rise A national SO2 market is active NOx is traded in numerous regional markets Trading in Greenhouse gases...
The LORD Doesn't Know… Many who claim to know Him. The LORD doesn't know… Many who claim to know Him (Mat 7:21-23 NKJV) "Not everyone who says to Me, 'Lord, Lord,' shall enter the kingdom of heaven, but he who...
The carbon cycle. Changes in atmospheric carbon dioxide levels. Relationship between gas concentrations and the enhanced greenhouse effect. The precautionary principle. Use of precautionary principle to justify action. Effects of global warming on arctic ecosystems. J WERBA - IB BIOLOGY
EEO Investigations (Closures) The measure for FY 07 : 50% of complaints filed will be closed within the regulatory time frames. Definitions: A closure is an investigation where the notice of election is sent to the complainant or a case...
Download Presentation
Ready to download the document? Go ahead and hit continue!