H-Disorders 1

  1. chromosomes
    • -structures that carry DNA inside cells
    • -humans have 46 grouped into 23 pairs
    • -23rd is sex linked chromosomes
  2. Gene
    segment of DNA on a chromosome that determines a trait
  3. alleles
    • -diff. forms or values of a gene that an individual may posses (blue/brown eyes)
    • -one comes from mom, one from dad
  4. homozygous
    the 2 alleles are the same
  5. heterozygous
    the 2 alleles are different (one will be dominant)
  6. hemizygous
    only 1 allele is present
  7. patterns of inheritance
    • -autosomal dominant
    • -autosomal recessive
    • -X-linked recessive
  8. autosomal dominant
    • -abnormal gene on an autosomal chromosome
    • -even if child receives only one of bad gene they are going to have the disorder
  9. Autosomal recessive
    • -involves abnormal gene on an autosomal chromosome
    • -defect only occurs if child receives two abnormal copies of the gene
    • -can be a carrier for the gene
  10. X-linked recessive
    • -sex linked recessive
    • -abnormal gene on the X chromosome
    • -in males a single abnormal gene will result in the defect since they only have one X
    • -in females only occurs if receive abnormal defect from both parents
  11. Mitochondrial inheritance
    • -small amt. of DNA stored in mitochondria of a cell
    • -mito. passed on by mom
    • -100% of kids will inherit that DNA but only females will pass it on
  12. Genetic Hearing Loss
    • two types:
    • -syndromic
    • -non-syndromic
    • -50% of HL is genetic, most often autosomal recessive, nonsyndromic
  13. syndromic HL
    • -there are other medical problems in addition to HL
    • -may be autosomal recessive, autosomal dominant, or X linked
  14. Outer Ear
    • -two parts: pinna, ear canal
    • -protection, amplification, sound localization
    • -Ear Canal (EAM)-outer 1/3 cartilage, inner 2/3 bone
  15. Conductive HL
    • -HL that's a result of a problem conducting sounds to the inner ear
    • -problems with outer and middle ear result in a conductive HL
  16. Congenital Anomalies
    • -dysplasia- abnormal development of an anatomical structure
    • -aplasia- lack of development
    • -microtia- small pinna
    • -anotia- pinna is absent
    • -aural atresia- absence of ear canal
    • -aural stenosis- narrow ear canal
  17. Congenital Aural atresia
    • -usually unilateral
    • -males>females
    • -usually present with microtia
    • -can cause variable degrees of conductive HL
  18. surgical outer ear reconstruction
    • -rib graft auricular reconstruction- start at 6 yrs, 3-4 surgeries
    • -Medpor (porous polyethylene) auricular reconstruction- start 3 yrs, 2 surgeries
  19. auricular prosthesis
    • -appropriate for patients with anotia
    • -made of silicone
    • -attached with adhesive or titanium screws
  20. Exostosis (surfers ear)
    • -abnormal bony growth on ear canal
    • -encouraged by swimming in cold water
    • -makes it easier for ear to become blocked by wax or debris
    • -surgically removed
  21. External Otitis
    • -swimmer's ear
    • -involves pain swelling, drainage, itching, and HL
    • -antibiotic drops
Card Set
H-Disorders 1