The Eyes and Ears

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Chapter 10

• The Eyes and Ears

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Function of the Eye

• Let light in
• Pupil
• Focus light
• Lens

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Function of the Eye

• Transform light into nerve impulses
• Retina
• Send nerve impulses to the brain
• Optic nerve

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Inner Eye Outer Layer

• Cornea
• Transparent anterior portion
• Allows light into the eye
• Helps focus light onto the back of the eye
• Sclera
• White of the eye
• Tough protective covering

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Inner Eye Middle Layer

• Middle layer also called the uvea
• Choroid
• Inner layer of sclera
• Contains blood vessels

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Inner Eye Middle Layer

• Ciliary body
• Ciliary muscles
• Adjust shape of the lens for focusing
• Ciliary process
• Produces aqueous humor

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Inner Eye Middle Layer

• Iris
• Colored portion
• Center is pupil

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Inner Eye Inner Layer

• Retina
• Several layers of nervous tissue
• Contain rods and cones that transform light into
  nerve impulses
• Fovea centralis
• Macula lutea
• Optic disc (blind spot)

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Inner Eye

• Lens
• Not part of the layers
• Held in place by suspensory ligaments

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Inner Eye

• Lens
• Bends the light
• Refraction
• Focuses light by changing shape
• Lens accommodation
• If elasticity is lost
• Reading glasses are needed

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Inner Eye Chambers Anterior

• Contains aqueous humor produced by ciliary
  processes
• Flows from posterior chamber through the pupil to
  anterior chamber

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Inner Eye Chambers Anterior

• As aqueous humor is produced
• Excess flows out trabecula into the canal of
  Schlemm and into venous system
• Inability to drain causes glaucoma

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Inner Eye Chambers Posterior

• Filled with vitreous humor
• Jelly-like
• Maintains spherical shape of the eyeball
• Holds retina firmly against the choroid
• Transmits light

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Outer Eye

• Orbital cavity
• Extrinsic ocular muscles
• Eyelids
• Conjunctival membrane
• Lacrimal apparatus

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Additional Word Parts Roots

• ambly/o dull dim
• Coagulati/o to condense to clot
• Dipl/o double
• Emmetr/o in proper measure
• Is/o equal

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Additional Word Parts Suffixes

• -conus cone-shaped
• -edema accumulation of fluid
• -iasis abnormal condition process
• -metrist specialist in the measurement of
• -ory pertaining to

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Additional Word Parts Prefixes

• Myein- to shut
• Presby- old age
• Pseudo- false

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Roots

• Aque/o water
• Blephar/o eyelid
• Chori/o choroid
• Choroid/o choroid membrane
• Conjunctiv/o conjunctiva
• Core/o pupil

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Roots

• Corne/o cornea
• Cycl/o ciliary body
• Dacryocyst/o lacrimal sac
• Goni/o angle (of the anterior chamber)
• Irid/o ir/o iris

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Roots

• Kerat/o cornea
• Lacrim/o tears
• Mi/o contraction less
• Mydri/o wide dilation dilatation
• Ocul/o eye
• Ophthalm/o eye

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Roots

• opt/o vision sight
• Palpebr/o eyelid
• Papill/o optic disc
• Phac/o phak/o lens
• Phot/o light
• Pupill/o pupil

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Roots

• Retin/o retina
• Scler/o sclera
• Ton/o tension
• Trabecul/o meshwork lattice
• Uve/o uvea
• Vitre/o glasslike gel-like

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Suffixes

• -chalasis relaxation
• -opia -opsia visual condition vision
• -tropia turning
• -tropion turning

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Aging Eye

• Lens becomes denser, harder, and thicker
• Reading glasses
• Presbyopia
• Changes in the way photoreceptors and pupils
  receive light
• Require more light to see

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Common Diseases Eye

• Cataracts
• Errors in refraction
• Hyperopia
• Myopia
• Astigmatism
• Glaucoma
• Macular degeneration

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Abbreviations Eye

• Accom accommodation
• OD (oculus dextra) right eye
• OS (oculus sinistra) left eye
• OU (oculus unitas) both eyes

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Abbreviations Eye

• PERLA pupils equal, react to light
  and accommodation

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Abbreviations Eye

• PRK photorefractive keratectomy
• EOM extraocular movement

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Abbreviations Eye

• IOL intraocular lens
• IOP intraocular pressure
• VA visual acuity
• VF visual field

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Ear

• Function
• Hearing
• Detection and transduction
• Prominent role in maintaining balance
• External ear
• Middle ear
• Inner ear

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External Ear

• Auricle or pinna
• External auditory meatus
• Eardrum or tympanic membrane

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Middle Ear

• Ossicles
• Tiny bones
• Malleus
• Incus
• Stapes

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Middle Ear

• Oval window
• Transmits sound to inner ear
• Eustachian tube
• Equalizes air pressure

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Inner Ear

• Bony labyrinth
• Perilymph
• Membranous labyrinth and endolymph
• Vestibule
• Semicircular canals
• Cochlea

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Roots

• Audi/o hearing
• Audit/o hearing
• Aur/o ear
• Cochle/o cochlea
• Labyrinth/o inner ear labyrinth
• Myring/o tympanic membrane eardrum

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Roots

• Ossicul/o ossicles
• Ot/o ear
• Salping/o eustachian tube
• Staped/o stapes
• Tympan/o tympanic membrane eardrum

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Suffix

• -cusis hearing

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Aging Ear

• Structural changes
• Decreased sound waves getting to the inner ear
• Loss of hearing
• Presbycusis
• Decreased sense of balance

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Common Diseases Ear

• Deafness
• Conductive
• Sensorineural

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Common Diseases Ear

• Menieres Disease
• Hearing loss
• Pressure in the ear
• Vertigo
• Tinnitus

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Abbreviations Ear

• AC air conduction
• AD (auris dextra) right ear
• AS (auris sinistra) left ear
• AU (auris unitas) both ears
• BC bone conduction

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Abbreviations Ear

• EENT eyes, ears, nose, throat
• ENT eyes, nose, throat
• HD hearing distance
• NIHL nerve-induced hearing loss
• TM tympanic membrane