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Sensory SystemSensory System
Unit- LUnit- L
Special SensesSpecial Senses The EyeThe Eye
1” in diameter1” in diameter Protected by orbital Protected by orbital
socket of skullsocket of skull, , eyebrows, eyelashes eyebrows, eyelashes and eyelids.and eyelids.
Bathed in fluid from Bathed in fluid from Lacrimal GlandsLacrimal Glands
( ( tears empty into tears empty into nasal cavitynasal cavity))
Conjunctiva – thin Conjunctiva – thin membrane that lines membrane that lines the eyelids the eyelids and covers and covers part of the eye.part of the eye.
EyesEyes
3.03 Remember the structures of the sensory 3.03 Remember the structures of the sensory systemsystem 33
The EyeThe Eye Wall of Eye is made up of 3 layers or Wall of Eye is made up of 3 layers or
coatscoats Sclera, Choroid Coat, and the RetinaSclera, Choroid Coat, and the Retina
SCLERASCLERA- Outer layer- Outer layer White of the eyeWhite of the eye Tough, fibrous capsule helps maintain shape Tough, fibrous capsule helps maintain shape
of eye and protects the structure within.of eye and protects the structure within. EXTRINSIC MUSCLES- muscle responsible for EXTRINSIC MUSCLES- muscle responsible for
moving the eye that are attached to the moving the eye that are attached to the sclera.sclera.
The Other EyeThe Other Eye CorneaCornea – Front of – Front of
sclerotic coat (part of sclerotic coat (part of sclera)sclera) Clear part (no blood Clear part (no blood
vessels) – called the vessels) – called the “window of the eye”“window of the eye”
Transparent so light Transparent so light rays can pass through rays can pass through
Gets O2 and nutrients Gets O2 and nutrients through lymphthrough lymph
I can see you….I can see you…. Choroid CoatChoroid Coat
Middle layerMiddle layer Contains blood vesselsContains blood vessels Circular opening in front is the PUPILCircular opening in front is the PUPIL Colored, muscular layer Colored, muscular layer surrounding pupil surrounding pupil
is is IRISIRIS INTRINSIC MUSCLES - change size of iris to INTRINSIC MUSCLES - change size of iris to
control amount of light entering through control amount of light entering through the pupil – exposed to light = constrictionthe pupil – exposed to light = constriction
Can you see me??Can you see me?? LensLens
Crystalline structure located behind iris and pupil – Crystalline structure located behind iris and pupil – focuses light rays on retina – function is focuses light rays on retina – function is accommodation = adjusting for near / far visionaccommodation = adjusting for near / far vision
Elastic, disc-shaped, biconvexElastic, disc-shaped, biconvex
Situated between the anterior and posterior Situated between the anterior and posterior chamberschambers
ANTERIOR CHAMBER filled with AQUEOUS HUMOR, a watery fluid.
POSTERIOR CHAMBER filled with transparent, jellylike substance - VITREOUS HUMOR
Both substances maintain eye’s spherical shape and refract light rays
Hey…where did you go??Hey…where did you go??
Oh no!! It’s dark in here!!Oh no!! It’s dark in here!! RetinaRetina
Innermost layer – 3Innermost layer – 3rdrd coat of the eye – located coat of the eye – located between the posterior chamber and choroid coatbetween the posterior chamber and choroid coat
Light rays focus an image on the retinaLight rays focus an image on the retina The image then travels to the cerebral cortex via the The image then travels to the cerebral cortex via the
OPTIC NERVE.OPTIC NERVE.
If light rays do not focus correctly on the retina, the If light rays do not focus correctly on the retina, the condition may be corrected with properly fitted condition may be corrected with properly fitted contact lenses, or eyeglasses, which bend the light contact lenses, or eyeglasses, which bend the light rays as required.rays as required.
Finally…the eye is almost Finally…the eye is almost over!over!
Retina contains specialized cells, visual receptors - Retina contains specialized cells, visual receptors - rods and conesrods and cones
RODSRODS- sensitive to - sensitive to dim light…problems driving at dim light…problems driving at night….damage to rodsnight….damage to rods
CONESCONES – sensitive to bright light – responsible for – sensitive to bright light – responsible for color visioncolor vision
OPTIC DISC- OPTIC DISC- on the on the retinaretina, known as the blind spot- , known as the blind spot- nerve fibers gather here to form the optic nervenerve fibers gather here to form the optic nerve, no , no rods or cones.rods or cones.
Posterior Vitreous Posterior Vitreous DetachmentDetachment
My story…My story…
The EyeThe Eye Pathway of VisionPathway of Vision
LIGHTLIGHT
RODS & CONESRODS & CONES( Pick up stimulus)( Pick up stimulus) OPTIC NERVEOPTIC NERVE BRAINBRAIN
CORNEACORNEA PUPILPUPILLENS (Light LENS (Light
rays are refracted)rays are refracted)
RETINARETINA
The EarThe EarOuter EarOuter Ear PINNAPINNA (AURICLE)- (AURICLE)-
outer ear, collects outer ear, collects sound wavessound waves
EXTERNAL AUDITORY EXTERNAL AUDITORY CANAL- ear canalCANAL- ear canal
CERUMENCERUMEN- earwax, - earwax, protects the earprotects the ear
TYMPANIC TYMPANIC MEMBRANE- ear MEMBRANE- ear drum, separates outer drum, separates outer and middle ear.and middle ear.
Can you hear me??Can you hear me?? Middle EarMiddle Ear
Cavity in temporal boneCavity in temporal bone Connects with pharynx by EUSTACHIAN TUBE Connects with pharynx by EUSTACHIAN TUBE
- - which equalizes pressure in the middle ear which equalizes pressure in the middle ear with outside atmosphere.with outside atmosphere.
Bones in Bones in middle emiddle ear transmits sound waves ar transmits sound waves from ear drum to inner ear.from ear drum to inner ear.
1.1. MALLEUS (hammer)MALLEUS (hammer)2.2. INCUS (anvil)INCUS (anvil)3.3. STAPES (stirrup)STAPES (stirrup)
I can hear you I can hear you Inner EarInner Ear
ContainsContains spiral shaped organ of hearing - the spiral shaped organ of hearing - the COCHLEACOCHLEA
The cochlea contains a membranous tube, the The cochlea contains a membranous tube, the cochlear duct- which is filled with fluid that vibrates cochlear duct- which is filled with fluid that vibrates when sound waves are transmitted by the stapes.when sound waves are transmitted by the stapes.
ORGAN OF CORTI-ORGAN OF CORTI- in the cochlea in the cochlea - delicate hairlike - delicate hairlike cells that pick up vibrations of fluid and transmit cells that pick up vibrations of fluid and transmit them as a sensory impulse along the auditory nerve them as a sensory impulse along the auditory nerve to the brain.to the brain.
SEMICIRCULAR CANALS-SEMICIRCULAR CANALS- three structures in the inner three structures in the inner ear, contain liquid that is set in motion by head and ear, contain liquid that is set in motion by head and body movements- impulses sent to cerebellum to body movements- impulses sent to cerebellum to help maintain body balance (equilibrium).help maintain body balance (equilibrium).
Where does the sound go?Where does the sound go? Pathway of HearingPathway of Hearing
Sound waves Sound waves PinnaPinna External External Auditory CanalAuditory Canal Tympanic Tympanic MembraneMembrane Ossicles ( malleus, Ossicles ( malleus, incus, & stapes)incus, & stapes) Cochlea CochleaAuditory nerveAuditory nerve BrainBrain
Understanding the Understanding the functions of the earfunctions of the ear
Pathway of Pathway of hearinghearingTrace the Trace the pathway of pathway of hearing.hearing.Discuss the Discuss the process of hearing.process of hearing.What are What are decibels?decibels?
3.04 Understand the functions 3.04 Understand the functions and disorders of the sensory and disorders of the sensory
systemsystem 1919
DecibelDecibel Unit used to measure the intensity of Unit used to measure the intensity of
sound.sound.
The Nose & TongueThe Nose & Tongue NoseNose
Smell accounts for 90% of tasteSmell accounts for 90% of taste Tissue in the nose, olfactory Tissue in the nose, olfactory
epithelium, contains specialized nerve epithelium, contains specialized nerve cell receptors.cell receptors.
Those receptors stimulate the Those receptors stimulate the OLFACTORY NERVE OLFACTORY NERVE to the brain.to the brain.
TongueTongue Mass of muscle tissueMass of muscle tissue Bumps, projections, on the surface are Bumps, projections, on the surface are
papilla, they contain the TASTE BUDS.papilla, they contain the TASTE BUDS. Receptors in the taste buds send Receptors in the taste buds send
stimuli through 3 cranial nerves to the stimuli through 3 cranial nerves to the cerebral cortex.cerebral cortex.
Structures of the noseStructures of the nose
3.03 Remember the structures of the sensory 3.03 Remember the structures of the sensory systemsystem 2222
Structures of the noseStructures of the nose
3.03 Remember the structures of the sensory 3.03 Remember the structures of the sensory systemsystem 2323
Discuss the structures
Discuss the structures
of the nose in relation
of the nose in relation
to the to the
olfactory nerve.olfactory nerve.
Trivia TongueTrivia Tongue Did you know…Did you know…
Taste is the weakest of the five sensesTaste is the weakest of the five senses We have almost 10,000 taste buds inside We have almost 10,000 taste buds inside
our mouths; even on the roofs of our our mouths; even on the roofs of our mouthsmouths
Everyone’s tongue print is different Everyone’s tongue print is different similar to fingerprintssimilar to fingerprints
3.03 Remember the structures of the sensory 3.03 Remember the structures of the sensory systemsystem 2424
Structures of the tongueStructures of the tongue Taste Taste
receptorsreceptors Also known Also known
as gustatory as gustatory buds or taste buds or taste budsbuds
3.03 Remember the structures of the sensory 3.03 Remember the structures of the sensory systemsystem 2525
What type of What type of
tissue is tissue is
the tongue the tongue
made?made?
Common Sensory Disorders Common Sensory Disorders Disorders of the EyeDisorders of the Eye
CONJUCTIVITISCONJUCTIVITIS Pink eyePink eye Inflammation of Inflammation of
conjunctival membranes conjunctival membranes in front of the eyein front of the eye
Redness, pain, swelling, Redness, pain, swelling, and dischargeand discharge
Highly contagious Highly contagious Rx- antibiotic eye dropsRx- antibiotic eye drops
GlaucomaGlaucoma Excessive intraocular pressure Excessive intraocular pressure causing destruction causing destruction
of the retina and atrophy of the optic nerveof the retina and atrophy of the optic nerve Caused by over production of aqueous humor, lack Caused by over production of aqueous humor, lack
of drainage, or aging.of drainage, or aging. Symps- develop gradually – mild aching, loss of Symps- develop gradually – mild aching, loss of
peripheral vision, halo around the lightperipheral vision, halo around the light TONOMETER- measures intraocular pressureTONOMETER- measures intraocular pressure Rx – drugs or laser surgery to decrease intraocular Rx – drugs or laser surgery to decrease intraocular
pressurepressure
Eye disordersEye disorders
Eye DisordersEye Disorders Glaucoma: Glaucoma:
Common Sensory DisordersCommon Sensory Disorders CATARACTSCATARACTS
Lens of eye gradually becomes cloudyLens of eye gradually becomes cloudy Frequently occurs in people over 70Frequently occurs in people over 70 Causes a painful, gradual blurring and loss of visionCauses a painful, gradual blurring and loss of vision Pupil turns from black to milky whitePupil turns from black to milky white Rx- surgical removal of the lensRx- surgical removal of the lens
Macular DegenerationMacular Degeneration Eye disorder that occurs with agingEye disorder that occurs with aging The macula ( part of the retina responsible for sharp color The macula ( part of the retina responsible for sharp color
vision) degeneratesvision) degenerates Vision is reduced but usually doesn’t cause total blindness.Vision is reduced but usually doesn’t cause total blindness.
Still problems with the eyeStill problems with the eye Detached RetinaDetached Retina
May occur with aging- accident can cause it at younger May occur with aging- accident can cause it at younger ageage
Retina detaches from choroid Retina detaches from choroid Symps- loss of peripheral vision and then central visionSymps- loss of peripheral vision and then central vision Rx- laser or freezing technique Rx- laser or freezing technique
STY ( HORDEOLUM)STY ( HORDEOLUM) Abscess at the base of an eyelash (in sebaceous gland)Abscess at the base of an eyelash (in sebaceous gland) Symps- red, painful and swollenSymps- red, painful and swollen Rx- warm, wet compressesRx- warm, wet compresses
Eye ProblemsEye Problems Sty:Sty:
Eye InjuriesEye Injuries Tears are effective in cleaning the eyeTears are effective in cleaning the eye If glass or fragments get in eye, cover both If glass or fragments get in eye, cover both
eyes and see medical treatment. (DO NOT eyes and see medical treatment. (DO NOT remove the object)remove the object)
Night blindness = NYCTALOPIA- due to Night blindness = NYCTALOPIA- due to inactive rodsinactive rods
Color blindness- cones are affected – Color blindness- cones are affected – genetic disorder that carried by the female genetic disorder that carried by the female and transmitted to males.and transmitted to males.
Eye InjuriesEye Injuries Color Blind TestingColor Blind Testing
Do you need glasses?Do you need glasses? PRESBYOPIAPRESBYOPIA
Lens loses elasticityLens loses elasticity, cant focus on close or distant objects, cant focus on close or distant objects Usually occurs after age 40Usually occurs after age 40 Rx- bifocals Rx- bifocals
HYPEROPIAHYPEROPIA FarsightedFarsighted Focal point beyond the retina because eyeball too shortFocal point beyond the retina because eyeball too short Convex lenses helpConvex lenses help
MYOPIAMYOPIA Nearsighted – Nearsighted – can’t see far awaycan’t see far away Eyeball too longEyeball too long Concave lenses helpConcave lenses help
Eye doctor =
Eye doctor =
Opthamologist
Opthamologist
Eye ProblemsEye Problems Presbyopia:Presbyopia:
Hyperopia: Hyperopia:
Eye ProblemsEye Problems Myopia: Myopia:
Still more eye problemsStill more eye problems AMBLYOPIAAMBLYOPIA
Reduction or dimness of visionReduction or dimness of vision
ASTIGMATISMASTIGMATISM Irregular curvature of the cornea or lens, causing blurred vision and Irregular curvature of the cornea or lens, causing blurred vision and
eye straineye strain Rx- corrective lensesRx- corrective lenses
DIPLOPIA- double visionDIPLOPIA- double vision
STABISMUS ( cross-eyes)STABISMUS ( cross-eyes) Eye muscles do not coordinate their actionsEye muscles do not coordinate their actions Usually in childrenUsually in children Rx – eye exercises or surgeryRx – eye exercises or surgery
Opthalmoscope = used
Opthalmoscope = used
to examine the eye
to examine the eye
Eye ProblemsEye Problems Amblyopia:Amblyopia:
Astigmatism: Astigmatism:
Eye ProblemsEye Problems Diplopia: Diplopia:
Eye ProblemsEye Problems Cross-eyed: Cross-eyed:
Disorders of the EarDisorders of the EarLoud noiseLoud noise
Hearing is fragile! Loud noise over a Hearing is fragile! Loud noise over a period of time can cause period of time can cause hearing losshearing loss..
Symptoms- Symptoms- TINNITUSTINNITUS (ringing in ears) and (ringing in ears) and difficulty understanding what people are difficulty understanding what people are sayingsaying
Conductive hearing lossConductive hearing loss….may be from ….may be from excessive wax in ear canalexcessive wax in ear canal
Disorders of the EarDisorders of the Ear Sensorineural: damage to parts of Sensorineural: damage to parts of
the inner ear or auditory nerve that the inner ear or auditory nerve that results in partial or complete results in partial or complete deafnessdeafness
Disorders of the EarDisorders of the EarOTITIS MEDIAOTITIS MEDIA
Infection of the middle earInfection of the middle ear Often a complication of a common cold in Often a complication of a common cold in
childrenchildren Rx- antibioticsRx- antibiotics If chronic or if fluid builds up- MYRINGOTOMY If chronic or if fluid builds up- MYRINGOTOMY
(opening in the tympanic membrane) with (opening in the tympanic membrane) with tubes inserted will relieve the pressure.tubes inserted will relieve the pressure.
Sxs – Sxs – fever, pain, fluid drainagefever, pain, fluid drainage
Otitis MediaOtitis Media
Other Sensory ProblemsOther Sensory Problems Phantom PainPhantom Pain
After an amputation your brain still sends signals to After an amputation your brain still sends signals to amputated limb. Neural pathways are still intact.amputated limb. Neural pathways are still intact.
RhinorrheaRhinorrhea Allergies cause constant, clear drainage Allergies cause constant, clear drainage
from nose and down pharynx from from nose and down pharynx from maxillary sinuses. May cause chronic maxillary sinuses. May cause chronic pharyngitis.pharyngitis.
Other Sensory ProblemsOther Sensory ProblemsThrushThrush (oral yeast infection characterized by white patches on (oral yeast infection characterized by white patches on
tongue and cheeks)tongue and cheeks)
Antibiotics wipe out normal flora which allow Antibiotics wipe out normal flora which allow fungi to flourish…vaginal and oral yeast fungi to flourish…vaginal and oral yeast infections are common with antibiotic useinfections are common with antibiotic use
Other Sensory ProblemsOther Sensory Problems Thrush: Thrush: