Chp 11 Sensory Organs MedTerms Definitions

  1. canthus
    angle where the eyes meet
  2. cilia
    hair cells
  3. tarsus
    provides stiffness of the eye giving shape
  4. conjunctiva
    provides protective layering
  5. what are the three layers of the eye?
    • sclera: white part of the eye; maintains shape, tough fibrous tissue
    • chroid: middle layer that contains many blood vessels
    • retina: sensitive and innermost layer; receives nerve impulses and transmits them to the brain
  6. anterior chamber vs. posterior chamber
    • anterior chamber: behind the cornea, in front of the iris
    • posterior chamber: behind the iris, in front of ligaments

  7. posterior segment
    makes up 2/3 of the eyeball filling it with vitreous humor that contains millions of fibers.
  8. rods vs. cones
    • rods: black and white
    • cones: color
  9. macula
    light sensitive area in the center of the retina
  10. fovea centralis
    middle pit of macula and contains ONLY CONES, no rods since it has high concentrations of color
  11. optik disc
    "blind spot" NO CONES AND RODS
  12. uvea
    pigmented layer of the eye
  13. ciliary body
    located in chroid layer, set of muscles that adjust thickness of lens to focus.
  14. iris
    colorful circular structure that surrounds the pupil; controls amount of light passing through by contracting muscles
  15. cornea
    focuses light rays entering the eye
  16. pupil
    black circular opening which permits light to enter the eye
  17. accommodation
    process whereby the eyes make adjustments for seeing objects at various distances
  18. convergence
    inward movement of the eyes towards each other
  19. emmetropia
    normal relationshpi between the refractive POWER for the eye and the SHAPE of the eye that enables light rays to focus correctly on the retina
  20. refraction
    ability of the lens to bend light rays so they focus on the retina
  21. visual acuity
    ability to distinguish object details and shape at distance
  22. ptosis
    drooping of the upper eye lid due to paralysis
  23. chalazion
    nodule or cyst usually on the upper eye lid
  24. ectropion
    eversion of the eyelid; turning it outwards
  25. entropion
    inversion edge of the eyelid; inward eyelid
  26. hordeolum
    "stye" pus filled and painful lesion on the eye
  27. periorbital edema
    swelling of the tissues surrounding the eye(s)
  28. subconjunctival hermorrhage
    bleeding between the conjunctiva and the sclera
  29. uveitis, iritis
    inflammation of the uvea
  30. corneal abrasion
    scratch to cornea
  31. diabetic retinopathy
    damage to retina due to complication of DM
  32. anioscoria
    condition where the pupils are unequal in size
  33. cataracts
    loss of transparency of the lens that causes a progressive loss of visual clarity
  34. floaters (vitreous floaters)
    particles of cellular debris that float in the vitreous humor casting shadows
  35. photopsia
    presence of what appears to be flashes of light
  36. miosis
    contraction of pupil in response to light, prescription of illegal drugs
  37. mydriasis
    dilation of the pupil caused by injury, disease or drugs
  38. nystagmus
    involuntary, constant movement of the eyeball.
  39. papilledema (choked disc)
    swelling and inflammation of the optic nerve at point of entrance through optical disc
  40. retinitis pigmentosa
    progressive degeneration of the retina that affects night and peripheral vision.
  41. glaucoma
    group of diseases characterized by increased intraocular pressure that damages the retinal nerve fibers and optic nerve. BLOCKAGE OF FLOW OUT OF THE EYE.
  42. open angle glaucoma (chronic)
    trabecular mesh is gradually blocked causing pressure
  43. closed angle glaucoma (acute)
    fluid cannot reach trabecular mesh causing pressure in the front of the eye
  44. macular degeneration
    progressive condition where macula is damaged, resulting in loss of vision; not blind.
  45. diplopia
    double vision
  46. hemianopia
    blindness in one half of the visual field
  47. monochromatism
    color blindness
  48. nycatalopia
    night blindness
  49. photophobia
    excessive sensitivity to light causing headache
  50. presbyopia
    change in vision relating to aging
  51. strabismus
    disorder in which the eyes point in a different direction or are not aligned correctly
  52. esotropia
    cross eyed
  53. exotropia
    snake eyes
  54. refractive disorder
    focusing problem that occurs when lens and cornea do not bend light
  55. ametropia
    images do not focus properly on the retina
  56. astigmatism
    uneven curvatures of the cornea causing inability to focus
  57. hyperopia
  58. myopia
  59. amblyopia
    dimness of vision; partial loss
  60. scotoma
    "blind spot" abnormal diminished vision surrounded by an area of normal vision.
  61. snellen chart
    chart measures visual acuity
  62. diopter
    unit of measurement of the lens' refractive power
  63. PERRLA
    Pupils are Equal, Round, Responsive, to Light and Accomodation
  64. enucleation
    removal of the eyeball
  65. concave lens
    inward; for myopia, nearsighted
  66. convex lens
    for hyperopsia; farsighted
  67. retinopexy
    used to reattach the detached area in a retinal detachment
    • pinna (auricle): external portion of the ear
    • external auditory canal: transmits sound waves to tympanic membrane
    • cerumen: earwax
    • tympanic membrane: eardrum
    • mastoid process: temporal bone containing hollow air space that surrounds the middle ear.
  70. auditory ossicles
    • malleus; hammer
    • incus; anvil
    • stapes; stirrup
  71. eustachian tube
    auditory tube; equalizes air pressure
    • oval window; vibrations enter through here
    • cochlea; sound vibrations are converted into impulses
    • organ of Corti; receives vibrations and relays them to auditory nerve fibers.
    • semicircular canals
    • acoustic nerves
  73. air conduction
    sound waves enter the ear through the pinna and travel down the external auditory canal then strike the eardrum
  74. bone conduction
    eardrum vibrates and causes the auditory ossicles of middle ear to vibrate.
  75. sensorineural conduction
    sound vibrations reach the inner ear.
  76. barotrauma
    pressure related condition caused by change in altitude; flying in an airplane, driving in the mountains.
  77. cholesteatoma
    epidermal cyst in the middle composed of epithelial cells and cholesterol
  78. otosclerosis
    ankylosis of the bones of the middle ear; conductive hearing loss
  79. menieres disease
    rare chronic disorder in which the amount of fluid in the inner ear increases intermittently.
  80. tinnitus
    ringing, buzzing in the ear.
  81. presbycusis
    gradual loss of sensorineural hearing
  82. conductive hearing loss
    occurs when sound waves are prevented from passing from the air to the fluid filled inner ear; earwax buildup, infection,
  83. sensorineural hearing loss
    damage to hair cells within the ear. "nerve deafness"
  84. weber and rinne tests
    use of a tuning fork to distinguish between conductive and sensorineural hearling losses
  85. fenestration
    surgical procedure in which a new opening is created in the labyrinth to restore hearing loss
Card Set
Chp 11 Sensory Organs MedTerms Definitions
sensory organs