Hard hearing

Anatomy
1. Tympanic membrane
2. Middle ear
Hearing pathway
1. Hair cells of the organ of Corti
  1. Bipolar cells of the spiral (cochlear) ganglion
    1. Cochlear nerve (CN VIII)
      1. Cochlear nuclei
        Trapezoid body
        Superior olivary nucleus
        Lateral lemniscus
        Nucleus of the inferior colliculus
        Medial geniculate body
        Auditory radiation
        Transverse temporal gyri of Heschl
Physiology of hearing
1. Sound collected through external ear
  1. Sound travels through ear canal
    1. Vibrates eardrum
      1. Vibrates ossicles
        Sound ripples hair cells
        Auditory nerve conducts impulse to brain
2. Impedance matching
  1. Sound waves converted into pressure waves in fluid
    1. acoustic impedance of fluid is much greater than that of air
      1. combination of the tympanic membrane and ossicles act as an impedance matching device in order to transfer the same frequency as the original sound waves
        Done via 2 mechanisms
        Increased force of movement of stapes
        The surface area of TM
Causes of ear discharge
1. Ear infections
  1. Foreign body impaction
    1. Mastoiditis
2. Ear examination
  1. Otoscope
    1. Tuning fork
      1. Audiometry
      2. Rinne's test
        Conductive hearing loss
      3. Weber's test
        Sensorineural hearing loss
Otits media
1. Symptoms
  1. Ear pain
    1. Vertigo
      1. Tinnitus
      2. Spinning sensation even though the body is stationary with respect to the surrounding.
    2. Wax buildup
    3. Sore throat
    4. Foreign object
2. infection of the middle ear
3. Complications
  1. Cholesteatoma
    1. destructive and expanding growth consisting of keratinizing squamous epithelium in the middle ear and/or mastoid process
    2. Aural polyp
      1. growth in the outside (external) ear canal or middle ear. It may be attached to the eardrum (tympanic membrane), or it may grow from the middle ear space.
4. Management
  1. Ibuprofen or acetaminophen
  2. Antibiotics
    1. Amoxicillin
      1. Ceftriaxone

Nächster

Hard hearing

Beschreibung

Zusammenfassung der Ressource

Medienanhänge

ähnlicher Inhalt

	Erstellt von Fatima Alkhateeb vor etwa 6 Jahre