Title: Midterm Study Guide
Course: 15SP-HIS-120-W02-A & P OF AUDITORY AND SPEECH > Section: Lessons

- HIS 120: ANATOMY AND PHYSIOLOGY
- MIDTERM STUDY GUIDE
- The Outer Ear
  - Also referred to as the auricle or pinna
    - Funnels sounds into the earcanal
    - Pinna Effect=Most efficient at picking up high-frequency sounds due to the geography of the outer ear (folds, crevasses)
    - Also aids in localization to sound (tell what direction sounds are coming from)
    - Pathologies or problems of the outer ear
      - Anotia=absence of the outer ear
      - Microtia=malformation of the outer ear
  - The External Auditory Canal (EAC)
    - Aka external auditory meatus or earcanal for short
    - ~1 inch (2.5cm) long in adults
    - Actually an elliptical shape, NOT round
    - The outer 2/3 of the EAC in cartilaginous
    - The inner 1/3 (closest to eardrum) is bony
    - Cerumen, or wax, is made in the earcanal
    - Most common pathologies or problems of the earcanal:
      - Wax build-up
      - Otalgia=ear pain
      - Otitis Externa=aka swimmer’s ear or outer ear infection (bacterial)
      - Atresia=absent or closed earcanal
      - Stenosis=narrowing of EAC
      - Otomycosis=fungal infection of EAC
      - Exostoses=bony growth in EAC, common in cold water swimmers
      - Osteoma=bony tumor in EAC
  - The Tympanic Membrane (TM) or eardrum
    - Separates the outer ear from the middle ear
    - Concave, disc-like structure which vibrates in response to sound entering the EAC.  This vibration sets into motion the middle ear bones
    - Attached to the malleus, the largest and first middle ear bone
    - Composed of 3 layers
    - Annulus=ring of tissue surrounding the TM which attaches it to the EAC
    - Pars tensa=largest surface area of TM that is taut or tense; composed of medial (middle) and inferior (bottom-most) portion of TM
    - Pars flaccida=looser and smaller area of TM; most superior or topmost part of TM
    - Umbo=the point on the TM where the greatest retraction/movement occurs
    - The TM is visualized using an otoscope.  The process of viewing the TM through an otoscope is called otoscopy, and should ALWAYS be performed before a hearing test.
    - Most common pathologies or problems of the tympanic membrane:
      - Myringitis=inflammation of TM
      - Tympanosclerosis=thickening and scarring of the TM
      - Perforation=a hole or tear in the TM

- The Middle Ear
  - Air-filled space between outer and inner ear
    - acts as the impedance-matcher between outer and inner ear
      - overcomes the loss of energy when sound is transmitted from one medium (air in the outer ear) to another (fluid in the inner ear)
  - Ossicles
      - the 3 smallest bones of the body: malleus, incus, stapes AKA hammer, anvil, and stirrup
  - The stapedius and tensor tympani muscles
  - The Eustachian tube
    - Connects the middle ear to the back of the throat (nasopharynx)
    - Purpose is to equalize pressure between the middle ear and regular, atmospheric pressure in earcanal
    - More horizontally oriented in young children=more likely to get ear infections
  - Most common middle ear pathologies:
    - Otitis media (OM)=middle ear infection
      - Otitis media with effusion (fluid)
      - May be acute (sudden onset) or chronic (long-lasting)
    - Eustachian tube dysfunction=malfunction of Eu tube (popping, crackling, pressure pain)
    - Patulous Eustachian tube
      - Eustachian tube is stuck open (patent)
      - Autophony, hearing one’s own voice in head, is common complaint
    - Otosclerosis
      - Bony growth over stapes footplate and fixation to oval window
    - Ossicular chain discontinuity
      - Loss of connection between the ossicles; usually due to head injury
    - Cholesteatoma
      - An erosive tumor composed of skin, protein, and fats
  - Treatment for Conductive HL
    - Medical
      - Antibiotic eardrops, oral antibiotics for bacterial infections
    - Surgical
      - Myringotomy (incision in TM), pressure-equalization tubes, ossicular repair, stapedectomy (removal of stapes and prosthesis placement)
    - Amplification

- The Inner Ear
  - Contains our organs of hearing and balance
    - Cochlea
      - 3 chambers: scala vestibuli, scala media, scala tympani
      - Oval and round windows
      - Contains endolymph and perilymph
      - Traveling wave theory
    - Semicircular canals and otolith
      - Superior, posterior, and horizontal SCCs detect changes in rotation of head
      - Otolith=utricule and saccule; detect changes in linear movements of head
      - All contain endolymph
  - Most common inner ear pathologies (typically results in sensorineural hearing loss)
    - Presbycusis=Age-related hearing loss; effects the high frequencies first
    - Noise-Induced Hearing Loss (NIHL)
    - Meniere’s disease
    - Ototoxicity
    - Perilymph fistula=Hole (fistula) at the oval window
    - Superior Semicircular Canal Dehiscence=Hole or thinning of the bony lining of the superior SCC; results in CONDUCTIVE loss
  - Treatment for SNHL
    - Hearing Aids, Hearing Assistive Technology, Cochlear Implants
    - CANNOT be treated medically
  - Most Common Vestibular Disorders
    - Benign paroxysmal positional vertigo (BPPV)
    - Meniere’s disease
    - Vestibular neuritis
    - Vestibular labyrinthitis
    - Migraine
  - Tinnitus and Hyperacusis

Attached Files: | - HIS 120 MIDTERM STUDY GUIDE.docx.pdf