anatomy ear

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anatomy ear
2013-06-11 11:58:49
anatomy ear

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  1. the hearing mechanisms consists of what 3 divisions?
    the external, middle, and inner ear
  2. function of external ear:
    particularly associated with protection but also with resonance and transmission
  3. middle ear function:
    is associated with absorption and transformation of acoustic wave energy into mechanical vibratory energy
  4. inner ear function:
    absorbs and transforms mechanical energy into a series of neural impulses which then is interpreted by the CNS into acknowledgment and interpretation of sound
  5. outer ear consists of:
    auricle (or pinna) and external auditory meatus
  6. middle ear consists of:
    drum membrane and auditory ossicles
  7. inner ear consists of:
    vestibular system and cochlea
  8. lateral 1/3 to 1/2 of the auditory meatus is _______, while medial portion is _______.
    • lateral: cartilaginous
    • medial: osseous
  9. The skin lining the meatus is adherent to the _________.  
    the lateral 1/3 of the canal has ________ which produce Cerumen
    • periosteum and perichondrium
    • cilia and modified sebaceous glands
  10. what are the 3 layers of the tympanic membrane?
    • skin
    • fibers
    • mucous membrane
  11. what does the ear do when sound gets too loud?
    The bones of the middle ear are supported by muscles which normally allow free motion but can tighten up and inhibit the bones' action when the sound gets too loud.
  12. the lateral 1/3 of the auditory tube is _______
    bone and short
  13. the medial 2/3 of the auditory tube pass thru a partial tube of ______ which is attached to _______________.
    • cartilage
    • to the base of the skull with its medial end projecting through the mucosa of the nasopharynx
  14. the auditory tube is normally closed. when does it open? and what muscles open it?
    opens momentarily when we swallow or yawn by the action of levator palati and tensor palati muscles
  15. what is the purpose for the occasional opening of the auditory tube?
    meant to keep the atmospheric pressure equalized on both sides of the tympanic membrane
  16. A delicate membranous                                    inner ear(labyrinth) is enclosed and protected by:
    a bony chamber that is referred ti as the bony labyrinth
  17. what type of components make up the inner ear?
    • hearing (auditory)--- cochlea
    • balance (vestibular)--- semicircular canals and the vestibule
  18. how is the cochlea involved with hearing?
    As the stapes pushes back and forth against the cochlea, it compresses the fluid to create waves in the fluid-filled compartments. Depending on the characteristics of the waves, specific nerve messages (impulses) are created. These messages then travel through the cochlear nerve (the hearing branch of the eighth cranial nerve) to the base of the brain (brainstem) and brain where they are interpreted.
  19. what CN is responsible for the sense of hearing and it is also pertinent to balance?
    Cranial nerve VIII: The eighth cranial nerve is the vestibulocochlear nerve
  20. what are the 5 organs housed in the inner ear that are responsible for vestibular (balance) system?
    vestibular organs are the three semicircular canals, the saccule, and the utricle. (The saccule and the utricle make up the vestibule.)
  21. what are the semi circular canals responsible for?
    what is the saccule and the utricle responsible for?
    • The semicircular canals:  detection of rotation (angular acceleration).
    • Saccule and utricle: detection of straight-line (linear) acceleration and gravity.