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EAR (Internal ear (Membranous labyrinth (Enlargement in the center…

- - - - Utriculus
        
        3 semicircular duct - balance
        
        End of each duct ampullae close to utriculus
        
        Endolymph set to motion by head movement
        
        Pressure on minute barrier (cristae ampullares)
        
        Deflect sensory hair from receptor --> nerve impulse
        
        Maculae in walls of succulus and utriculus
        
        detect head position
      - Succulus
        
        cochlear duct - hearing
- - - - Receives sound
  - - - Prevent dust from tympanic membrane
- - - - Thin partition btw meatus and tympanic cavity
      - Slanted: Dorsal surface more lateral than ventral
        
        Larger surface
      - Fibrous tissues btw epidermis and mucosa attaches the membrane to osseous tympanic ring of temporal bone
      - Handle of malleus embed in the medial side
        
        pull membrane medially, hollowing lateral surface
    - - Vestibular window: more dorsal, lead to vestibule
      - Cochlear window: lead to cochlear [cavity]
    - - Ossicles
        
        Tensor tympani
        
        Upper part of malleus handle
        
        Pull tympanic membrane inward when vibrate (tense it)
        
        Supplied by trigeminal n. (mandibular branch)
        
        Stapedius
        
        Neck of stapes
        
        Damps down vibration, minimize overly loud sounds to inner ear
        
        Supplied by facial n.
        
        Malleus
        
        Head articulates wt body of stapes
        
        Perceive and magnify oscillation from tympanic membrane
        
        Incus
        
        Articulates with body of stapes
        
        Stapes
        
        base sit in vestibular window
        
        Set in motion, cause vibration of fluid in inner ear
        
        Stimulates neuroreceptor cells
    - - Equalization of pressure
      - Narrow lumen, laterally compressed, usually collapsed
      - Opens to lateral wall of nasopharynx
        
        Marked by accumulation of lymphoid body (tubal tonsils)
    - - Enlarged bulbous extensions, may help in perceiving vy. low and high frequencies