1 / 25

The “Ear” is housed within the TEMPORAL BONE

The “Ear” is housed within the TEMPORAL BONE. The Outer Ear Consists of:. The Pinna - cartilaginous, highly variable in appearance, some landmarks. External Auditory Canal (or external auditory meatus) - 2.5 cm tube. Pinna Landmarks. Helix Antihelix Concha Tragus Intertragal Notch

vanida
Download Presentation

The “Ear” is housed within the TEMPORAL BONE

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The “Ear” is housed within the TEMPORAL BONE

  2. The Outer Ear Consists of: • The Pinna - cartilaginous, highly variable in appearance, some landmarks. • External Auditory Canal (or external auditory meatus) - 2.5 cm tube.

  3. Pinna Landmarks • Helix • Antihelix • Concha • Tragus • Intertragal Notch • Antitragus

  4. External Auditory Canal • lateral portion-cartilage • medial portion-osseous • lined with epidermal (skin) tissue • hairs in lateral part • cerumen (ear wax) secreted in lateral part.

  5. Outer Ear Functions • Amplification / Filtering • Protection • Localization

  6. The Middle Ear:A cleft within the temporal bone • Lining is mucous membrane • Tympanic Membrane separates it from EAC • Eustachian tube connects it to nasopharynx • Also Connected to Mastoid Air Cells

  7. Middle Ear Structures 1- Malleus 2- Incus --Ossicles 3- Stapes 4- Tympanic Membrane (Eardrum) 5- Round Window 6- Eustachian Tube

  8. Middle Ear Muscles 1.The StapediusAttaches to Stapes,Contracts in Response to Loud sounds, chewing, speaking; Facial (VIIth cranial) nerve 2. The Tensor TympaniHelps open Eustachian tube

  9. Middle Ear Functions • Impedance Matching • Filtering • Acoustic Reflex

  10. These sounds get through the middle ear most readily

  11. INNER EAR Two Halves: • Vestibular--transduces motion and pull of gravity • Cochlear--transduces sound energy (Both use Hair Cells)

  12. Within S. Media is the Organ of Corti

  13. The Stereocilia on IHCs and OHCs • OHCs (at top) • V or W shaped ranks • IHC (at bottom) • straight line ranks

  14. Cochlear Functions • Transduction- Converting acoustical-mechanical energy into electro-chemical energy. • Frequency Analysis-Breaking sound up into its component frequencies • Bekesy’s Traveling Wave • Active Tuning from OHCs

  15. Afferent & Efferent Neurons

  16. IHC activation alters firing rate

  17. Afferent neurons have their cell bodies in the Spiral Ganglion (4)

  18. Major Components of the Central Auditory Nervous System (CANS) • VIIIth cranial nerve • Cochlear Nucleus • Superior Olivary Complex • Lateral Lemniscus • Inferior Colliculus • Medial Geniculate Body • Primary Auditory Cortex <Trapezoid Body> Brainstem Mid-brain Thalamus Temporal Lobe

  19. AUDITORY CORTEX MEDIAL GENICULATE BODY INFERIOR COLLICULUS LATERAL LEMNISCUS SUPERIOR OLIVARY COMPLEX COCHLEAR NUCLEUS

  20. Mid-Saggital View of Brain 4th Ventricle Corpus Callosum Cerebellum Thalamus Pons

  21. Cortical Processing • Pattern Recognition • Duration Discrimination • Localization of Sounds • Selective Attention

  22. Cerebral Dominance/Laterality • Language Processing in the left hemisphere. (Remember the right ear has the strongest connections to the left hemisphere) • Most people show a right-ear advantage in processing linguistic stimuli

More Related