Transcript SPECIAL SENSES COOPERx

SPECIAL SENSES
EYES,
EARS,
NOSE
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The Eyes have it!:
Lacrimal glands..produce tears to
moisten and cleanse the eye
Conjunctiva..mucous membrane that
lines eyelids and covers front of eye for
extra protection
Sclera..”white” of eye,tough connective
tissue that maintains shape of eye
Cornea..circular,transparent part of the
front of the sclera
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Parts of the Eye
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Parts of the Eye
Choroid coat..middle layer interlaced
with blood vessels that nourish eye
Retina..inner most layer of nerve cells
which transmits light impulses to optic
nerve
Iris.. Colored portion of eye located
behind cornea
Pupil..opening, center of the
iris,regulates amount of light entering
eye
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Parts of the Eye
Lens.. circular structure behind pupil, it
refracts(bends) light to focus on retina
Aqueous humor..clear watery fluid that
fills space between cornea and iris
Vitreous humor..jellylike substance that
fills area behind lens helps shape
eyeball and refracts light
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Parts of the Eye
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Diseases & Disorders of the Eye
Amblyopia..lazy eye
Astigmatism..abnormal shape of eye
causing blurred vision
Conjuntivitis..pink eye, contagious
infection caused by bacteria or virus
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Diseases & Disorders of the
Eye
Cataract..cloudy or opaque lens causing
blurred vision, halos, and gradual vision
loss
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May result from trauma or aging
Treated by surgical removal of lens
Symptoms include blurred vision, halos
around lights, gradual vision loss, milkywhite pupil in later stages
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Diseases & Disorders of the
Eye
Glaucoma..increased intraocular
pressure caused by excess aqueous
humor.
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Common after age 40
Leading cause of blindness
Symptoms include loss of peripheral vision,
halos around lights,limited night vision and
mild aching
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Diseases & Disorders of the Eye
Hyperopia..farsightedness,image focused
behind the retina
Myopia..nearsightedness,image focused in
front of the retina
Presbyopia..farsightedness caused by loss of
lens elasticity in the normal aging process
(glasses or contacts)
Strabismus..eyes do not focus together due
to muscle weakness,eyes may cross (eye
exercise or surgery)
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“LEND ME YOUR EARS”
The ear is the organ that controls
hearing and balance
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Transmits sound waves to the auditory
nerve (vestibulocochlear)
Impulses go on to brain for interpretation
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THE EAR
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PARTS OF THE EAR
Pinna or auricle..outer ear,elastic
cartilage covered by skin
External Auditory canal..external tube
or canal of ear
Tympanic membrane..eardrum,
membrane that separates outer ear
from middle ear,vibrates when sound
waves hit it,transmits to middle ear
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PARTS OF THE MIDDLE EAR
Small space or cavity in the temporal
bone containing ossicles(3 small bones)
which transmit sound waves to inner
ear
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Malleus
Incus
Stapes
Eustachian tube..connect the middle ear to
the pharynx(throat)and equalizes pressure
on both sides of the eardrum
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PARTS OF THE INNER EAR
Oval window..membrane that separates inner
ear from middle ear
Vestibule..acts as entrance to inner ear
Cochlea..delicate hair-like cells shaped like a
snail’s shell,receptor of sound
Semicircular canals..contain liquid and
delicate hair like cells that bend when liquid
moves with head and body movement to
maintain balance.
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DISEASES & DISORDERS
Otitis Externa..inflammation of external
auditory canal caused by bacterium or virus
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Caused by swimming in contaminated water
Inserting bobby pins, fingernail, and swabs into
ear
Otitis Media.. Inflammation or infection of
middle ear caused by bacterium or virus,
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freq. follows sore throat
Symptoms include pain,vertigo,nausea,vomiting &
fluid buildup in middle ear
Treatment: myringotomy & insertion of tubes
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DISEASES & DISORDERS
Meniere’s disease..fluid collection with
degeneration of the hair cells in the
cochlea and vestibules causing vertigo
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Symptoms severe vertigo, tinnitis,
nausea,vomiting, loss of balance, tendency
to fall
Otosclerosis..immobile stapes with
conductive hearing loss
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DISEASES & DISORDERS
Hearing loss
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Conductive or deafness ..sound waves not
conducted to inner ear
 Wax(cerumen) plug
 Foreign body obstruction
 Infection
 Otosclerosis
 Ruptured tympanic membrane
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DISEASES & DISORDERS
Sensory hearing loss occurs when
damage to inner ear or auditory nerve
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Cannot be corrected
Cochlear implants may help somewhat
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THE TONGUE & TASTE
Mass of muscle tissue with projections
called papillae, where taste buds are
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THE NOSE & SMELL
Nose..organ of smell
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Impulses from olfactory receptors carried
to brain by olfactory nerve
More sensitive than taste
Can detect over 6,000 different smells
Food does not taste good when smell is
affected.
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SKIN & GENERAL SENSES
General sense receptors for pressure,
heat, cold ,touch, and pain located
throughout the body in skin &
connective tissue
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Each receptor perceives only one type
sense
Messages from these receptors allows the
body to respond to it’s environment.
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