Transcript Sensory PP

Special Senses
The Eye
The Eye
• 1” in diameter
• Protected by orbital
socket of skull,
eyebrows, eyelashes
and eyelids
• Bathed in fluid from
Lacrimal Glands-tears
empty into nasal cavity
• Conjunctiva- thin membrane that lines the
eyelids and covers part of the eye,
secretes mucous to lubricate the eye.
• Wall of the eye made of three coats.
• Sclera- outer layer, white of the eye,
tough coating helps maintain shape of eye
and protects what’s inside
• Muscles responsible
for moving the eye are
attached to the sclera
–called extrinsic
muscles
• Intrinsic Muscles:
change size of iris to
control amount of
light entering through
the pupil.
• Lens-crystalline structure
located behind iris and
pupil
• Elastic, disc-shaped,
biconvex
• Situated between the
anterior and posterior
chambers
• Anterior Chamber filled
with Aqueous Humor, a
watery fluid
• Posterior Chamber-filled
with transparent jellylike,
substance-vitreous humor.
• Cornea- front of scleraclear part (no blood
vessels)
• Transparent so light rays
can pass though
• Gets O2 and nutrients
through the lymph.
• Choroid Coat-Middle layer,
contains blood vessels,
Opening in front is the
PUPIL
• Colored muscular layer
surrounding pupil is iris.
• Retina-innermost
layer, light rays focus
an image on the retina,
the image travels to
the cerebral cortex
via the optic nerve. If
light rays don’t focus
properly on the retina
corrective lenses can
bend the light rays as
required. Retina
contains specialized
cells –rods and cones
• Rods –sensitive to dim light
• Cones- sensitive to bright light and
color.
• Optic Disc-on the retina, known as
the blind spot-nerve fibers gather
here to form the optic nerve, no rods
or cones.
Pathway of Vision
» Cornea » Pupil »
Lens (where
light rays
are
refracted)
Rods and Cones » Optic
»
Nerve
(pick up
stimulus)
» Retina »
Disorders of the Eye
• Conjunctivitis- pink
eye, Inflammation of
conjunctival
membranes in front of
the eye.
• Symptoms: Redness,
pain, swelling, and
discharge. Highly
contagious.
• Treatment-antibiotic
eye drops
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Glaucoma
Excessive intraocular
pressure causing
destruction of the retina
and atrophy of the optic
nerve
Caused by overproduction
of aqueous humor, lack of
drainage, or aging
Symp-develop gradual mild
aching, loss of peripheral
vision, halo around the
light
Tonometer-measures
intraocular pressure
Rx- drugs or laser surgery
Cataracts
• Lens of eye gradually
becomes cloudy
• Frequently occurs in
people over 70
• Causes painful gradual
blurring and loss of
vision
• Pupil turns from black
to milky white
• Rx-surgical removal of
the lens.
Sty (Hordeolum)
• Abscess at the
base of an eyelash
( in sebaceous
gland)
• Symp-red, painful
and swollen
• Rx-warm, wet
compresses
Detached Retina
• May occur with aging
or as a result of a
traumatic accident.
• The vitreous fluid
contracts as it ages
and pulls on the retina
causing a tear.
• Symptoms: loss of
central vision
• It is important
to get annual eye
examinations.
• Treatment: laser
or freezing
technique.
Vision Defects
• Presbyopia- lens loses
elasticity, can’t focus on
close or distant objects
• Usually occurs after the
age of 40
• Rx- Bifocals
• Hyperopia-Farsighted
• Focal point beyond the
retina because eyeball too
short
• Convex lenses help
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Myopia- nearsighted
Eyeball too long
Concave lenses help
Amblyopia- reduction or dimness of vision
Astigmatism-Irregular curvature of the cornea or lens,
causing blurred vision and eye strain
Rx- corrective lenses
Strabismus-(cross-eyes)
Eye muscles do no coordinate their actions
Usually in children
Rx- eye exercises or surgery
Diabetic Retinopathy
Diabetes can harm your
eyes. It can damage the
small blood vessels in you
retina, that back part of
your eye.
Cause diabetes is poorly
controlled or you have
diabetes a long time.
• Symptoms:
Trouble seeing
at night,
floaters in eyes,
blurred vision,
slow vision loss.
Macular Degeneration
• Occurs as a person ages.
• In the central part of the retina is the
macula which is responsible for sharp
central vision.
• Symptoms: Dimming or distortion of vision
that is most obvious at night.
• Two Type:
Dry: gradual thinning of the retina.
Wet: Leakage under retina causing a
blister involving blood vessels.
Treatment: Laser treatment.
• Ophthalmoscopeinstrument for viewing
inside the eye.
• Snellen eye chartchart that uses
letters or symbols in
calibrated heights to
check for vision
defects
Color blindness
• Color blindness occurs
when there is a
problem with the
color-sensing granules
(pigment) in certain
nerve cells of the eye.
These cells are called
cones.
• If just one pigment is
missing, you may have
trouble telling the
difference between
red and green.
• This is the most
common type of color
blindness. If a
different pigment is
missing you may have
trouble seeing blueyellow colors. People
with blue-yellow color
blindness usually have
problems identifying
red and greens too.
Colorblindness Continued
• Most color
blindness is due to
a genetic problem.
• About 1 in 10 men
have some form of
color blindness.
Very few women
are color blind.
This is no known
treatment. However,
there are special
contact lenses and
glasses that may help
people with color
blindness tell the
difference between
similar colors.
Test: Ishihara Color
Vision Test
The Ear
Hearing and equilibrium
3 parts: Outer, Middle, and Inner ear
Outer Ear
• Pinna-(auricle) outer ear, collects
sound waves.
• External Auditory Canal – ear canal
• Cerumen- earwax, protects the ear
• Tympanic membrane- ear drum,
separates outer and middle ear.
Middle Ear
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Cavity in temporal lobe.
Connects with pharynx by
Eustachian Tube which
equalizes pressure in the
middle ear with outside
atmosphere.
• Bones in middle ear that
transmit sound waves from
ear drum to inner ear
1. Malleus (hammer)
2. Incus (anvil)
3. Stapes (stirrup)
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Contains spiral shaped organ of hearing – the cochlea
The cochlea contains a membranous tube, the cochlear duct- which
is filled with fluid that vibrates when sound waves are transmitted
by the stapes.
Organ of Corti- delicate hairlike cells that pick up vibrations of
fluid and transmit them as a sensory impulse along the auditory
nerve to the brain.
Semicircular Canals- three structures in the inner ear, contain
liquid that is set in motion by head and body movements-impulses
sent to cerebellum to help maintain body balance (equilibrium).
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Pathway of
Hearing
Sound
• A sound byte is a short bit of sound
or clip from a longer recording.
• The doctor you would go to if you had
a problems with your ears, nose,
throat would be a otolaryngologist.
• The instrument used for looking in
your ears is a otoscope.
Disorders of the Ear
• Loud noise and
hearing losshearing is fragile.
Loud noise over a
period of time can
cause hearing loss.
External Otitis Media
• External Otitis Media: external
otitis, is typically a bacterial
infection of the outer ear canal skin
and can occur in acute and chronic
forms. Proper ear care can avoid
most infections.
Otitis Media
• Infection of the middle
ear
• Often a complication of a
common cold in children
• RX antibiotics
• If chronic or if fluid builds
up –myringotomy (opening
in the tympanic membrane)
with tubes inserted will
relieve the pressure.
Otosclerosis
• Is and inherited
disorder in which
the bones stapes
of the middle ear
first becomes
spongy and they
hardens. This
causes the stapes
to become fixed.
• This is a common
cause of deafness
in young adults.
• Stapedectomy a
total replacement
of the stapes is
the treatment of
choice.
Meniere's Disease
• A condition that
affects the
semicircular canals
of the inner ear.
• Causing narked
vertigo (dizziness).
• Vertigo can occur
at any time without
• Warning.
• Causing the patient to
be frightened.
• Vertigo is
accompanied by
nausea, vomiting, and
ringing in the ears.
• Treatment bed-rest,
medication may be
given to relieve the
vertigo and nausea.
• Cause is unknown.
Tinnitus
• Is a sensations of ringing or buzzing
that is perceived in the ear in the
absence of an actual sound stimulus.
• May be caused by impacted wax,
otitis media, otosclerosis, or loud
noise.
Presbycusis
• Is a condition that causes deafness
due to the aging process. This can be
helped with the use of hearing aids.
The Nose
Smell accounts for 90% of taste.
Tissue in the nose, olfactory epithelium, contains specialized
nerve cell receptors.
Those receptors stimulate the Olfactory Nerve to the brain
Structures of the nose
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Nares
Nasal Cilia
Nasal Septum
Olfactory receptors
Turbinates
Disorders of the Nose
• Rhinitis- Inflammation
of the lining of the
nasal congestion,
drainage, infection,
fumes, odors, emotion,
or drugs.
• Deviated Septum.
is a condition in which
there is a bend in the
cartilage structure
of the septum.
Disorders of the Nose
Cont
Symptoms: blockage of airflow through
one nostril, difficulty sleeping,
headaches, loud breathing, snoring.
Treatment: breathing strips,
Septoplasty.
Nasal Polyps
• These are growths in
the nasal cavity
associated with
rhinitis.
• Cause: People with the
following conditions
are more likely to also
have nasal polyps:
• Aspirin sensitivity,
asthma, cystic
fibrosis, and hay
fever
• In severe cases
surgery may be
necessary to
remove polyps.
The Tongue
Mass of muscle tissue.
Bumps on the surface are Papillae, they
contain the taste buds
Receptors in taste buds send stimuli
through 3 cranial nerves to the cerebral
cortex
Did you Know ….
• Taste is our weakest of the five
senses.
• We have almost 10,000 taste buds,
inside our mouths; even on the roof
of our mouth.
• Everyone’s tongue print is different
similar to fingerprints.
Disorders of the tongue
• Glossitis: Inflammation of the
tongue.
• Treatment: good oral hygiene.
• Strawberry tongue: due to scarlet
fever, vitamin deficiency of B12,
Kawaski syndrome.
• Treatment: Treat the reason for the
condition.
Thrush
Thrush is a yeast infection of the
mucous membrane lining the mouth and
tongue.
Persons with poor health, very old, very
young, and people with HIV, and
someone getting chemotherapy.
Treatment: Can take nystatin mouth
wash or lozenges.
Did you know….
• Our eyes are always the same size
from birth, but our nose and ears
never stop growing!
• That hearing is the last sense to go
before someone dies.
Structures of the Skin
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Epidermal layer
Dermis layer
Subcutaneous layer
Touch receptors: tactile corpuscles
located in the skin.
• Temperature sensors
• Pain receptors.