SPECIAL SENSES BY JUDY LEVERETTE RN BSN

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SPECIALSENSESBY JUDY LEVERETTE RN BSN
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• SPECIAL SENSES ALLOW THE HUMAN BODY TO REACT TO
  THE ENVIRONMENT BY PROVIDING FOR SIGHT, HEARING,
  TASTE, SMELL, AND BALANCE.

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• SPECIAL SENSES OCCUR BECAUSE THE BODY HAS ORGANS
  THAT RECEIVE SENSATIONS, NERVES THAT CARRY THE
  MESSAGE TO THE BRAIN, AND A BRAIN THAT INTERPRETS
  AND RESPONDS TO THE MESSAGE.

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• THE EYE IS THE ORGAN THAT CONTROLS THE SPECIAL
  SENSE OF SIGHT.

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• THE EYE RECEIVES LIGHT RAYS AND TRANSMITS
  IMPULSES FROM THE RAYS TO THE OPTIC NERVE, WHICH
  CARRIES THE IMPULSES TO THE BRAIN, WHERE THEY ARE
  INTERPRETED AS VISION, OR SIGHT.

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• This is the optic nerve

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• LACRIMAL GLANDS IN THE EYE PRODUCE TEARS, WHICH
  CONSTANTLY MOISTEN AND CLEANSE THE EYE

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This is the lacrimal gland of the eye, where the
h is
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• A MUCOUS MEMBRANE, CALLED THE CONJUNCTIVA, LINES
  THE EYELIDS AND COVERS THE FRONT OF THE EYE TO
  PROVIDE ADDITIONAL PROTECTION AND LUBRICATION.

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CONJUNCTIVA
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• THE EYE IS PARTIALLY ENCLOSED IN THE BONY SOCKET
  OF THE SKULL. THIS HELPS PROTECT THE EYE.

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Eye socket helps protect the eye
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• EYELIDS AND EYELASHES HELP KEEP OUT DIRT AND
  PATHOGENS (GERMS)

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Eyelids and eyelashes
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• THE SCLERA, THE OUTERMOST LAYER OF THE EYE, IS
  FREQUENTLY REFERRED TO AS THE WHITE OF THE EYE

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The sclera
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• THE CORNEA IS A CIRCULAR, TRANSPARENT PART OF THE
  FRONT OF THE SCLERA. IT ALLOWS LIGHT RAYS TO
  ENTER THE EYE.

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THE CORNEA
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• THE IRIS IS THE COLORED PORTION OF THE EYE. IT IS
  LOCATED BEHIND THE CORNEA.

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THE IRIS, COLORED PORTION OF THE EYE
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• THE OPENING IN THE CENTER OF THE IRIS IS CALLED
  THE PUPIL.

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The pupil
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• THE IRIS CONTAINS 2 MUSCLES WHICH CONTROL THE
  SIZE OF THE PUPIL AND REGULATE THE AMOUNT OF
  LIGHT ENTERING THE EYE. IT IS THE PUPIL THAT THE
  LIGHT RAYS GO THROUGH.

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• THE LENS OF THE EYE IS A CIRCULAR STRUCTURE
  LOCATED BEHIND THE PUPIL IT REFRACTS (BENDS)
  LIGHT RAYS SO THE RAYS FOCUS ON THE RETINA.

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The lens of the eye
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• THE RETINA IS THE INNERMOST LAYER OF THE EYE. IT
  IS MADE OF MANY LAYERS OF NERVE CELLS, WHICH
  TRANSMIT THE LIGHT IMPULSES TO THE OPTIC NERVE.

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The retina of the eye
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The retina
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• THE AQUEOUS HUMOR IS A CLEAR, WATERY FLUID THAT
  FILLS THE SPACE BETWEEN THE CORNEA AND IRIS. THIS
  SPACE IS CALLED ANTERIOR CHAMBER.

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• THE AQUEOUS HUMOR GIVES THE FRONT OF THE EYE ITS
  FORM AND SHAPE AND REFRACTS LIGHT RAYS

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Anterior chamber which contains aqueous humor
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Another view of the anterior chamber
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• THE VITREOUS HUMOR IS THE JELLY-LIKE SUBSTANCE
  THAT FILLS THE AREA BEHIND THE LENS.

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The vitreous humor
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• THE VITREOUS HUMOR HELPS MAINTAIN THE SHAPE OF
  THE EYEBALL AND ALSO REFRACTS LIGHT RAYS.

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• WHEN LIGHT RAYS ENTER THE EYE, THEY PASS THROUGH
  A SERIES OF PARTS THAT REFRACT (bends) THE RAYS
  SO THAT THE RAYS FOCUS ON THE RETINA.

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• THESE PARTS ARE THE CORNEA, AQUEOUS HUMOR, THE
  PUPIL, THE LENS, AND THE VITREOUS HUMOR.

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• IF THE RAYS ARE NOT REFRACTED CORRECTLY BY THE
  VARIOUS PARTS, VISION CAN BE DISTORTED OR BLURRED.

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• THE RETINA IS MADE UP OF MANY LAYERS OF NERVE
  CELLS, AND 2 OF THESE CELLS ARE THE RODS AND
  CONES.

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• IN THE RETINA, THE LIGHT RAYS (image) ARE PICKED
  UP BY THE RODS AND CONES, CHANGED INTO NERVE
  IMPULSES, AND TRANSMITTED BY THE OPTIC NERVE TO
  THE OCCIPITAL LOBE OF THE CEREBRUM WHERE SIGHT IS
  INTERPRETED.

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Rods and cones
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• CONES ARE SENSITIVE TO COLOR AND ARE USED MAINLY
  FOR VISION WHERE IT IS LIGHT.

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• RODS ARE USED FOR VISION WHEN IT IS DARK OR DIM.

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Rods and cones
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• DISEASES AND ABNORMAL CONDITIONS FO THE EYE

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• AMBLYOPIA, OR LAZY EYE OCCURS IN EARLY CHILDHOOD.
  IT RESULTS IN POOR VISION IN ONE EYE AND AND
  CAUSED BY THE DOMINANCE OF THE OTHER EYE

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• LAZY EYE MEANS THAT ONE EYE HAS NOT DEVELOPED
  NORMALLY AND ALWAYS HAS BLURRED VISION, EVEN WITH
  THE BEST GLASSES OR CONTACTS THE EYE DOCTOR CAN
  PRESCRIBE

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What amblyopia or lazy eye looks like
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• IF AMBLYOPIA IS NOT TREATED BEFORE 8 TO 9 YEARS
  OF AGE, BLINDNESS OF THE AFFECTED EYE MAY OCCUR.

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• ASTIGMATISM IS AN ABNORMAL SHAPE OR CURVATURE OF
  THE CORNEA THAT CAUSES BLURRED VISION.

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• IN ASTIGMATISM, THE CORNEA IS SHAPED MORE LIKE A
  FOOTBALL, AN OVAL SHAPE, THAN THE NORMAL ROUND
  SHAPE LIKE A BASEBALL

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• TREATMENT FOR ASTIGMATISM INCLUDES EYE GLASSES,
  SPECIAL CONTACT LENSES, AND CERTAIN REFRACTIVE
  SURGERIES.

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• A CATARACT OCCURS WHEN THE NORMALLY CLEAR LENS
  BECOMES CLOUDY OR OPAQUE (an area you cannot see
  through)

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This is what a cataract looks like
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• MOST CATARACTS ARE RELATED TO AGING. SIGHT IS
  RESTORED BY SURGICAL REMOVAL OF THE LENS AND
  REPLACED WITH AN IMPLANTED LENS.

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• CONJUNCTIVITIS, OR PINK EYE, IS A CONTAGIOUS
  INFLAMMATION OF THE CONJUNCTIVA, USUALLY CAUSED
  BY A BACTERIA OR VIRUS.

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Conjuctivitis
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• ANTIBIOTICS, FREQUENTLY IN THE FORM OF AN EYE
  OINTMENT, ARE USED TO TREAT CONJUNCTIVITIS

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• GLAUCOMA IS A CONDITION OF INCREASED INTRAOCULAR
  (within the eye) PRESSURE CAUSED BY AN EXCESS
  AMOUNT OF AQUEOUS HUMOR.

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What happens to vision with glaucoma
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• GLAUCOMA IS A LEADING CAUSE OF BLINDNESS. IT IS
  USUALLY CONTROLLED WITH MEDICATIONS THAT DECREASE
  THE AMOUNT OF FLUID, OR IMPROVE DRAINAGE.

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• HYPEROPIA IS FARSIGHTEDNESS. PEOPLE CAN SEE
  DISTANT OBJECTS VERY WELL, BUT HAVE DIFFICULTY
  SEEING OBJECTS UP CLOSE

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• MYOPIA IS NEARSIGHTEDNESS. OBJECTS ARE SEEN
  DISTINCTLY ONLY WHEN NEAR TO THE EYE

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• PRESBYOPIA IS FARSIGHTEDNESS CAUSED BY A LOSS OF
  LENS ELASTICITY. PEOPLE EXPERIENCE BLURRED
  VISION AT NEAR POINTS,

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• SUCH AS WHEN READING, SEWING, OR WORKING AT THE
  COMPUTER. TREATMENT INCLUDES EYEGLASSES WITH
  BI-FOCALS OR READING GLASSES.

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• STRABISMUS IS WHEN THE EYES DO NOT MOVE OR FOCUS
  TOGETHER.

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• THE EYES MAY MOVE INWARD (CROSS-EYED), OR
  OUTWARD, OR UP OR DOWN.

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Strabismus
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MORE STRABISMUS
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THE EAR
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• THE EAR IS DIVIDED INTO 3 MAIN SECTIONS THE
  OUTER EAR, THE MIDDLE EAR, AND THE INNER EAR.

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• THE OUTER EAR CONTAINS THE VISIBLE PART OF THE
  EAR, CALLED THE PINNA, OR AURICLE.

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• THE OUTER EAR LEADS TO A CANAL OR TUBE CALLED THE
  AUDITORY CANAL. SPECIAL GLANDS IN THIS CANAL
  PRODUCE CERUMEN, A WAX THAT PROTECTS THE EAR.

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The auditory canal
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Cerumen or wax blockage in the auditory canal
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A cast of earwax after removal
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• SOUND WAVES TRAVEL THROUGH THE AUDITORY CANAL
  UNTIL THEY REACH THE EARDRUM, OR TYMPANIC
  MEMBRANE.

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• THE TYMPANIC MEMBRANE IS A THIN, SEMI-TRANSPARENT
  MEMBRANE SEPARATING THE OUTER EAR FROM THE MIDDLE
  EAR.

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THE EARDRUM VIEWED FROM WITHIN
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The eardrum
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• THE TYMPANIC MEMBRANE (EARDRUM) VIBRATES WHEN
  SOUND WAVES HIT IT AND TRANSMITS THE SOUND WAVES
  TO THE MIDDLE EAR

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• THE MIDDLE EAR IS A SMALL SPACE, OR CAVITY AND IT
  CONTAINS 3 SMALL BONES (ossicles)

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• THESE 3 SMALL BONES ARE CALLED THE HAMMER, ANVIL
  AND STIRRUP. THESE ARE THE SMALLEST BONES IN THE
  BODY, SMALL ENOUGH TO FIT COLLECTIVELY ON A U.S.
  DIME

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The ossicles of the middle ear
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Ossicles inside ear
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Another view of ossicles
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• THE OSSICLES ARE CONNECTED AND TRANSMIT SOUND
  WAVES FROM THE TYMPANIC MEMBRANE TO THE INNER EAR.

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• THE MIDDLE EAR IS CONNECTED TO THE PHARYNX, OR
  THROAT, BY A TUBE CALLED THE EUSTACHIAN TUBE.

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• THIS TUBE ALLOWS AIR TO ENTER THE MIDDLE EAR AND
  HELPS EQUALIZE AIR PRESSURE BETWEEN THE MIDDLE
  EAR AND THE OUTSIDE AIR.

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• WHEN YOU POP YOUR EARS AS YOU CHANGE ALTITUDE
  (going up a mountain or in an airplane), YOU ARE
  EQUALIZING THE AIR PRESSURE IN YOUR MIDDLE EAR

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Location of eustachian tube
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• THE INNER EAR IS THE MOST COMPLEX PORTION OF THE
  EAR. IT IS SEPARATED FROM THE MIDDLE EAR BY A
  MEMBRANE CALLED THE OVAL WINDOW.

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• THE FOOTPLATE OF THE ANVIL IS THE INNERMOST OF
  THE AUDITORY OSSICLES. ITS BASE IS INSERTED INTO
  THE OVAL WINDOW.

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The stirrup attached to oval window
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• THE 1ST SECTION OF THE INNER EAR IS THE
  VESTIBULE, WHICH ACTS AS THE ENTRANCE TO THE 2
  OTHER PARTS OF THE INNER EAR.

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The vestibule of inner ear
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• THE COCHLEA, SHAPED LIKE A SNAILS SHELL, IS
  INSIDE THE INNER EAR. IT CONTAINS DELICATE,
  HAIR-LIKE CELLS WHICH COMPOSE THE ORGAN OF CORTI,
  A RECEPTOR OF SOUND WAVES.

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The cochlea
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• THE ORGAN OF CORTI CAN BE THOUGHT OF AS THE
  BODYS MICROPHONE. IT IS CONTAINED INSIDE ONE OF
  THE 3 COMPARTMENTS OF THE COCHLEA.

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• THE ORGAN OF CORTI TRANSMITS THE IMPULSES FROM
  SOUND WAVES TO THE AUDITORY NERVE.

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• THE AUDITORY NERVE CARRIES SOUND WAVES IMPULSES
  TO THE TEMPORAL LOBE OF THE CEREBRUM, WHERE THEY
  ARE INTERPRETED AS HEARING

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The auditory nerve
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• THE SEMICIRCULAR CANALS ARE ALSO IN THE INNER
  EAR. THEY ARE FLUID FILLED TUBES THAT HELP YOU
  KEEP YOUR BALANCE

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• THESE CANALS ALSO HAVE DELICATE HAIR-LIKE CELLS
  THAT BEND WHEN THE LIQUID MOVES WITH HEAD BODY
  MOVEMENTS.

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• IF YOU SPIN AROUND AND THEN STOP, THE LIQUID
  INSIDE YOUR SEMICIRCULAR CANALS MOVES AROUND
  LONGER, AND THE LITTLE HAIRS,

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• ALSO INSIDE THE CANALS, CONTINUE TO SEND THE
  MESSAGE TO THE BRAIN THAT YOU ARE SPINNING EVEN
  THOUGH YOURE NOT!!

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Semicircular canals
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• DISEASES AND ABNORMAL CONDITIONS

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• HEARING LOSS IS CLASSIFIED AS EITHER CONDUCTIVE
  OR SENSORY.

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• CONDUCTIVE HEARING LOSS OR DEAFNESS OCCURS WHEN
  SOUND WAVES ARE NOT CONDUCTED TO THE INNER EAR.

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• POSSIBLE CAUSES INCLUDE A WAX (CERUMEN) PLUG, A
  FOREIGN BODY OBSTRUCTION, AN INFECTION OR A
  RUPTURED TYMPANIC MEMBRANE (EARDRUM)

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Normal and ruptured eardrum
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• SENSORY HEARING LOSS OR DEAFNESS OCCURS WHEN
  THERE IS DAMAGE TO THE INNER EAR OR AUDITORY
  NERVE. THIS CANNOT USUALLY BE CORRECTED.

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• MENIERES DISEASE RESULTS FROM A COLLECTION OF
  FLUID IN THE INNER EAR AND A DEGENERATION OF THE
  HAIR CELLS IN THE COCHLEA AND VESTIBULE

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• SYMPTOMS INCLUDE SEVERE VERTIGO (DIZZINESS),
  TINNITUS (RINGING IN THE EARS), NAUSEA
  VOMITING, LOSS BALANCE, AND A TENDENCY TO FALL.

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• OTITIS EXTERNA IS AN INFLAMMATION OF THE EXTERNAL
  AUDITORY CANAL CAUSED BY A PATHOGENIC ORGANISM.

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• SWIMMERS EAR, FOR EXAMPLE, IS CAUSED BY SWIMMING
  IN CONTAMINATED WATER.

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• INSERTING BOBBY PINS, FINGERNAILS, OR COTTON
  SWABS INTO THE EAR CAN ALSO CAUSE THIS CONDITION.

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Otitis externa
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Otitis externa
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• OTITIS MEDIA IS AN INFLAMMATION OR INFECTION OF
  THE MIDDLE EAR CAUSED BY A BACTERIA OR A VIRUS

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• INFANTS AND CHILDREN ARE VERY SUSCEPTIBLE TO
  OTITIS MEDIA BECAUSE THE EUSTACHIAN TUBE IS
  ANGLED DIFFERENTLY THAN IN ADULTS

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Normal eardrum on left, otitis media on the right
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• SYMPTOMS OF OTITIS MEDIA INCLUDE PAIN, FEVER,
  DIZZINESS AND FLUID BUILD-UP IN THE MIDDLE EAR

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• OTOSCLEROSIS OCCURS WHEN THE STIRRUP BECOMES
  IMMOBILE, CAUSING CONDUCTIVE HEARING LOSS

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• SYMPTOMS INCLUDE GRADUAL HEARING LOSS, TINNITUS,
  AND, AT TIMES, DIZZINESS.

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• SURGICAL REMOVAL OF THE STIRRUP AND INSERTION OF
  AN ARTIFICIAL STIRRUP CORRECTS THE
  CONDITION.(another word for stirrup is stapes)

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• THE TONGUE AND SENSE OF TASTE

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• THE TONGUE IS A MASS OF MUSCLE TISSUE WITH
  PROJECTIONS CALLED PAPILLAE. THE PAPILLAE CONTAIN
  TASTE BUDS.

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• TASTE BUDS ARE STIMULATED BY THE FLAVORS OF FOODS
  MOISTENED BY SALIVA

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• THERE ARE 4 MAIN TASTES
• SWEET TASTES AND SALTY TASTES AT THE TIP OF THE
  TONGUE

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Sweet and salty at tip of tongue
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• SOUR TASTE AT THE SIDES OF THE TONGUE

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• BITTER TASTES AT THE BACK OF THE TONGUE

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• TASTE IS INFLUENCED BY THE SENSE OF SMELL.

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• THE NOSE AND SENSE OF SMELL

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• THE NOSE IS THE ORGAN OF SMELL. THE SENSE OF
  SMELL IS MADE POSSIBLE BY OLFACTORY RECEPTORS

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• OLFACTORY RECEPTORS ARE LOCATED IN THE UPPER PART
  OF THE NASAL CAVITY

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Olfactory receptors
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Olfactory receptors
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• THE SENSE OF SMELL IS MORE SENSITIVE THAN TASTE.
  THE HUMAN NOSE CAN DETECT OVER 6,000 DIFFERENT
  SMELLS.

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• THE SENSE OF SMELL IS CLOSELY RELATED TO THE
  SENSE OF TASTE.

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• THIS IS CLEARLY ILLUSTRATED BY THE FACT THAT WHEN
  YOU HAVE A HEAD COLD AND YOUR SENSE OF SMELL IS
  IMPAIRED, FOOD DOES NOT TASTE AS GOOD.

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• GENERAL SENSE RECEPTORS FOR PRESSURE, HEAT, COLD,
  TOUCH AND PAIN ARE LOCATED THROUGHOUT THE BODY IN
  THE SKIN AND CONNECTIVE TISSUE

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• FOR EXAMPLE, THE SKIN CONTAINS SPECIAL RECEPTORS
  FOR HEAT AND DIFFERENT RECEPTORS FOR COLD

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• WHO WAS A VERY FAMOUS PERSON WHO LIVED A FULL
  LIFE WITHOUT BENEFIT OF SIGHT OR HEARING?

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Helen Keller
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• THE
• END