2Learning Outcomes31.1 Describe the anatomy of the nose and the function of each part.31.2 Describe how smell sensations are created and interpreted.31.3 Describe the anatomy of the tongue and the function of each part.31.4 Describe how taste sensations are created and interpreted.
3Learning Outcomes (cont.) 31.5 Name the four primary taste sensations and the acknowledged fifth taste sensation.31.6 Describe the anatomy of the eye and the function of each part, including the accessory structures and their functions.31.7 Trace the visual pathway through the eye and to the brain for interpretation.31.8 Identify ways that patients can practice preventive eye care.
4Learning Outcomes (cont.) 31.9 State ways that vision changes with age.31.10 List the medical professionals involved in diagnosis and treatment of visual disorders, including the roles that each play in patient care.31.11 List treatments for visual disorders.31.12 Describe the causes, signs and symptoms, and treatments of various diseases and conditions of the eye.
5Learning Outcomes (cont.) 31.13 Describe the anatomy of the ear and the function of each part.31.14 Explain the role of the ear in maintaining equilibrium.31.15 Explain how sounds travel through the ear and are interpreted in the brain.31.16 State ways that hearing changes with age.
6Learning Outcomes (cont.) 31.17 List the types of hearing loss and how they differ.31.18 Describe treatments for ear and hearing disorders.31.19 Explain how patients can be educated about preventive ear care.31.20 Describe the causes, signs and symptoms, and treatments of various disorders of the ear and hearing.
7Introduction Special senses Sensory receptors located in head Nose – smellTongue – tasteEyes – visionEars – hearing and equilibriumTouch is a generalized senseStimulus nervous system brain response
8Nose and Sense of Smell Olfactory receptors Chemoreceptors – respond to changes in chemical concentrationsChemicals must be dissolved in mucusLocated in the olfactory organ
9Smell Sensation Activation of smell receptors information sent to olfactory nervesthat send the information along olfactory bulbs and tractsto different areas of the cerebrum;cerebrum interprets the information as a particular type of smell
10Nose and Sense of Smell (cont.) Sensory AdaptationChemical can stimulate receptors for limited timeReceptors fatigue and stop responding to chemicalNo longer smell odor
11Very Good! Apply Your Knowledge You notice an odor coming from a patient when you enter the exam room. Why would the patient not be able to smell it?ANSWER: After a few minutes, smell receptors undergo sensory adaptation and no longer respond to the chemical, and the patient can no longer smell the odor.Very Good!
12Tongue and Sense of Taste Gustatory receptors – located on taste budsTaste budsLocationPapillae of the tongueRoof of mouthWalls of throat} fewer than on tongueTongue
13Tongue and Sense of Taste (cont.) Taste cells and supporting structuresOn taste budsSupporting structures fill in spaceTaste cellsChemoreceptorsChemicals in food and drink must be dissolved in saliva to activateTongue
14Tongue and Sense of Taste (cont.) Taste sensation4 primarySweet – tipSour – sidesSalty – tip and sidesBitter – backUmami5th basic tasteGlutamic acidSpicy foodsActivate pain receptorsInterpreted by brain as “spicy”Tongue
16Tongue and Sense of Taste (cont.) Taste sensationActivation of taste cellsCranial nervesGustatory cortex of cerebrum interprets information
17Apply Your Knowledge Great Job! What are the four primary taste sensations and where are their corresponding taste cells located?ANSWER: The four primary taste sensations are:Sweet – concentrated on the tip of the tongueSour – concentrated on the sides of the tongueSalty – concentrated on the tip and sides of the tongueBitter – concentrated on the back of the tongueGreat Job!
18Eye and Sense of Sight Vision system Eye Eyes Optic nerves Vision centers in the brainAccessory structuresEyeProcesses light to produce imagesThree layersTwo chambersSpecialized parts
19Eye and Sense of Sight (cont.) Outer – scleraWhite of the eyeProtects the eyeSense receptorsCorneaFront of eye“Window” that allows light into eyeBends light as it entersEye
20Eye and Sense of Sight (cont.) Middle – choroidContains blood vesselsIrisColored part of eyeMuscle that contracts and relaxes to open or close pupilRegulates the amount of light that enters the eyeCiliary bodyMusclesControls the shape of the lensLensPosterior to irisFocuses light on retinaAccommodationEye
21Eye and Sense of Sight (cont.) Inner – retinaVisual receptorsRodsSensitive to lightWill function in dim light – “limited” night visionDo not provide sharp image or detect colorConesFunction in bright lightSensitive to color and provide sharp imagesOptic disc – optic nerve enters retinaEye
22Eye and Sense of Sight (cont.) Chambers of the eyeAnterior chamberFront of lensFilled with aqueous humor – nourishes and bathes anterior eyePosterior chamberBehind lensContains vitreous humor – maintains shape of eyeball and holds retina in placeEye
24Visual Accessory Organs Eye orbitsEye socketsForm a protective shell around the eyesEyebrows protect eyesEyelidsSkin, muscle, and connective tissueBlinkingPrevents surface from drying outKeeps foreign material out of eye
25Visual Accessory Organs (cont.) ConjunctivasMucous membranesLine inner surfaces of eyelidsLacrimal apparatusLacrimal glandsLateral edge of eyeballsProduce tearsNasolacrimal ductsMedial aspect of eyeballsDrain tears into nose
26Visual Accessory Organs (cont.) Extrinsic eye musclesSix per eye move the eyeballSuperiorlyInferiorlyLaterallyMedially
27Visual Pathways Eye works like a camera Light enters the eye through the lensRefraction – cornea, lens, and fluids bend light to focus it on the retinaOptic chiasmImage upside down on retinaImage turned right-side upOccipital lobe of cerebrumRetina converts light to nerve impulseOptic nerve
28Eye Safety and Protection 90% of eye injuries are preventableEye safety practicesAdequate lighting/handrailsPad or cushion sharp edges on furnitureToys should be age-appropriateDo not mix chemicalsProper protective wearGogglesSports eye guards
29Out of Sight! Apply Your Knowledge ANSWER: Matching: ___ Middle layer of eye A. Lacrimal glands___ Eye sockets B. Aqueous humor___ Control shape of lens C. Retina___ Outer layer of eye D. Sclera___ Anterior chamber E. Vitreous humor___ Tears F. Ciliary body___ Bending of light G. Choroid___ Posterior chamber H. Orbits___ Inner layer of eye I. RefractionHFDBAIOut of Sight!EC
30The Aging Eye Eyelids may droop Quality and quantity of tears decrease Conjunctiva thins and eyes may become dryerCornea yellows, fat deposits around itBrown spots on scleraPupils become smallerLens denser and more rigidLens yellowsRetinal changes – vision fuzzyChanges in ability of eye to adapt to lightImpaired night visionDecreased peripheral vision; depth perceptionFloaters or flashes of light
31Preventing Falls in the Elderly Falls can result in fractures of major bonesComplications of falls can lead to deathProne to fallingVision problemsPoor healthSlower reflexesPatient educationSafety checklistPrecautionsEquilibrium problemsMedication
32Nice job! Apply Your Knowledge What vision changes can occur in the elderly patient?ANSWER: An elderly patient may have difficulty seeing because of drooping eyelids. Focusing may be more difficult because less light enters the eye. He may have difficulty distinguishing colors due to yellowing of the lens. Vision may be fuzzy because of changes in the retina. Night vision can become impaired. The patient may see floaters or “sparks.”Nice job!
33Vision Testing Professionals include Ophthalmologist – medical doctor who is an eye specialistOptometrist – provides vision screening and diagnostic testingOpticians – fills vision prescriptions for glasses and contacts
34Vision Screening Tests Myopia – impairment of distance visionEyeball is too longLight focuses anterior to retinaSnellen chartNormal vision20/20Hyperopia – impairment of near visionEyeball is shorterLight focused posterior to retinaTest using a handheld chart with various sizes of printPresbyopiaImpairment due to agingLoss of lens elasticity
35Vision Screening Tests (cont.) Contrast sensitivityDistinguish shades of grayTestingPelli-Robson contrast sensitivity chartVistech Consultants vision contrast systemDetect cataracts or retinal problems before sharpness is impairedColor visionColor-blindnessMay be inheritedMore common in malesTestsIshihara color systemRichmond pseudoisochromatic color testDifficulties may indicate retinal or optic nerve disease
36Reyeght! Apply Your Knowledge What is the difference between myopia and hyperopia and what is presbyopia? What effect does each have on vision?ANSWER: If the patient has myopia, the eyeball is elongated and light focuses in front of the retina. She will have difficulty seeing far away. If she has hyperopia, the eyeball is shorter than normal and light focuses behind the retina. With presbyopia, the lens loses elasticity due to aging, resulting in the inability to see things close up.Reyeght!
37Treating Eye ProblemsDelicate organ – caution and sterile technique necessaryPatient education on preventive careAdministration of medicationsOnly ophthalmic medicationsAvoid touching dropper or ointment tube to the eyeEye irrigationSterile solutionPurposeRemove foreign materialRelieve discomfort
38Common Diseases and Disorders Disorder/DiseaseDescriptionAmblyopiaLazy eye; one eye is not used regularly; poor depth perception; often concurrent with strabismusAstigmatismCornea or lens has abnormal shape; blurred imagesCataractsOpaque structures in lens prevent light from passing through; vision fuzzyConjunctivitisPink eye; highly contagious bacterial infection
39Common Diseases and Disorders (cont.) Disorder/DiseaseDescriptionDry eye syndromeCommon problem; decreased production of oil in tearsEntropionInversion of lower eyelidGlaucomaIncrease in intraocular pressure due to a buildup of aqueous humor in anterior chamberHyperopiaFarsightedness
40Common Diseases and Disorders (cont.) Disorder/DiseaseDescriptionMacular degenerationProgressive disease; inadequate blood supply to retina; most common cause of vision loss; affects people over 50 yearsMyopiaNearsightednessNystagmusRapid, involuntary eye movements
41Common Diseases and Disorders (cont.) Disorder/DiseaseDescriptionPresbyopiaLoss of lens elasticity; develops with ageRetinal detachmentLayers of retina separate; medical emergencyStrabismusConvergentDivergentMisalignment of eyesCrossed eyes; one or both eyes turn inwardWall eye; one or both eyes turn outward
42Apply Your Knowledge Correct! It is okay to use any solution or medication in the eye?ANSWER: Only medications or solutions specifically designated for ophthalmic use may be used in the eyes. Medications not designated for the eye may be too concentrated or contain substances that can injure the eye. Solutions should be sterile and care must be taken not to contaminate the tip of the dropper or bottle.Correct!
43The Ear External ear Auricle (pinna) External auditory canal Collects sound wavesExternal auditory canalGuides sound wave to tympanic membraneTympanic membraneSeparates external canal and middle earVibrates when sound hits itEar
44The Ear (cont.) Middle ear Eustachian tube Ear ossicles Oval window Connects middle ear to throatEqualizes pressure on eardrumOval windowSeparates middle ear from inner earMiddle earEar ossiclesMalleusIncusStapesOssicles vibrate in response to vibration of tympanic membraneEar
45The Ear (cont.) Inner ear – labyrinth of communicating chambers Semicircular canals – detect balance of the bodyVestibule – equilibriumCochleaHearing receptorsOrgan of Corti – organ of hearingEar
47EquilibriumHead movement causes fluid in semicircular canals and vestibule to moveEquilibrium receptors transmit information along vestibular nerves to cerebrumCerebrum determines if body needs to make adjustments
48Sense of Hearing Sound waves collected Waves cause tympanic membrane to vibrateOssicles amplify vibrations, which enter inner earMovement of hairs lining cochlea trigger nerve impulsesImpulses are transmitted by auditory nerve to the brain for interpretation
49Sense of Hearing (cont.) Bone conductionAlternative pathwayBypasses external and middle ear directly to innerUseful in determining cause of hearing problem
50Apply Your Knowledge Supear! ANSWER: Matching: ___ Pinna A. Organ of Corti___ Malleus, incus, and stapes B. Cerumen___ Hearing receptors C. Ear ossicles___ Inner ear D. Tympanic membrane___ Organ of hearing E. Auricle___ Earwax F. Cochlea___ Eardrum G. Labyrinth___ Detect balance of body H. Semicircular canalsCFGABDH
51How to Recognize Hearing Problems in Children GuidelinesInfants to 4 monthsStartled by loud noisesRecognize mother’s voice4 to 8 monthsRegularly follow soundsBabble at people8 to 12 monthsRespond to the sound of their nameRespond to “no”
52The Aging Ear External ear larger / earlobe longer Cerumen dryer and prone to impactionEar canal narrowerEardrum shrinks and appears dull and grayOssicles do not move as freelySemicircular canals less sensitive to changes in position – affects balance
53Apply Your KnowledgeWhat problem with the aging ear makes the elderly more prone to falls?ANSWER: The semicircular canals become less sensitive to change in position, which affects balance. This problem with equilibrium results in increased chance of falls in the elderly.Great Answer!
54Hearing Loss Symptom of a disease, not a normal part of aging Conductive hearing lossInterruption in transmission to inner earCausesObstruction of ear canalInfection of middle earReduced movement of stirrupSensorineural hearing lossSound waves not perceived by brain as soundCausesHereditaryRepeated exposure to loud noises/viral infectionsSide effect of medication
55Hearing Loss (cont.)Noise pollution – causes damage to sensitive cells in cochleaWorking with the hearing-impaired patientSpeak at a reasonable volume, in clear, low-pitched volumesFace the person; use hand gestures, if appropriateDo not overemphasize lip movementsHave patient repeat message to verify understandingTreat hearing-impaired patients with patience and respect
56Hearing and Diagnostic Tests Hearing testsTuning forks – differentiate between types of lossAudiometer – measures hearing acuityDiagnostic testingTympanometryMeasures the ability of the eardrums to moveDetects diseases and abnormalities of the middle ear
57Bravo! Apply Your Knowledge Identify the types of hearing loss based on the description below. What can be used to differentiate between the two?Answer:Conductive hearing loss Sensorineural hearing lossA tuning fork is a simple test to distinguish between types of hearing loss.Sound waves not perceived by brain as soundCausesHereditaryRepeated exposure to loud noises/viral infectionsSide effect of medicationInterruption in transmission to inner earObstruction of ear canalInfection of middle earReduced movement of stirrupBravo!
58Treating Ear and Hearing Problems Patient educationPreventative ear careAdminister ear medicationsMedications and irrigationRelieve inflammation or irritation of canalLoosen and remove impacted cerumen or foreign body
59Treating Ear and Hearing Problems (cont.) Hearing aidsObtaining a hearing aidOtologist – medical doctor specializing in health of earAudiologist – evaluates and corrects hearing problemsCare and useBatteriesRoutine cleaningKeep dry and avoid hair spraysOther devices / strategiesAmplifiersClosed-captioningAppliances that light up as well as ring
60Common Diseases and Disorders Disorder/DiseaseDescriptionCerumen impactionBuild up of wax within external auditory canalHearing lossDeafnessMénière's diseaseDisturbance in equilibrium characterized by vertigo and tinnitus
61Common Diseases and Disorders Disorder/DiseaseDescriptionOtitisOtitis externaOtitis mediaOtitis internaInflammation of the earSwimmers’ earMiddle ear infection; common infectionLabyrinthitis; inner ear infectionOsteosclerosisImmobilization of the stapes; common cause of conductive hearing lossPresbycusisHearing loss due to aging process
62Apply Your Knowledge Excellent! ANSWER: True or False: ___ An audiologist is a physician that specializes in ear health.___ Otitis media is also called swimmers’ ear.___ Presbycusis is hearing loss due to the aging process.___ Vertigo is ringing in the ears.___ Otitis interna is an inflammation of the labyrinth.___ Ménière's disease is characterized by disturbances in equilibrium.___ Otosclerosis is the immobilization of the stapes.___ Tinnitus is dizziness.FotologistFexternaTFTinnitusExcellent!TTTFVertigo
63In Summary31.1 Olfactory receptors, which are the sense receptors for the sense of smell, are found in the olfactory organ located in the upper part of the nasal cavity.31.2 When the olfactory receptors are activated, they send information to the olfactory nerves, then on to the cerebellum for interpretation.31.3 Gustatory receptors are found on the taste buds, which are located on the papillae (bumps) of the tongue.
64In Summary (cont.)31.4 Gustatory receptors are chemoreceptors which are activated by the chemicals found in food and drink as they are dissolved in the mouth’s saliva. The information is brought to the gustatory cortex of the parietal lobe of the brain for interpretation.31.5 The four primary taste sensations are, sweet, salty, sour and bitter. Each has a “specialized” area of the tongue where each taste is most pronounced. The fifth recognized taste sensation is umami.
65In Summary (cont.)31.6 The eye is composed of three layers. The sclera is the outer protective layer and includes the cornea. The middle vascular layer is the choroid, consisting of the iris, pupil, ciliary body, and lens, and is the area of light regulation and focusing. The innermost layer is the retina containing the rods and cones, the optic nerve, and optic disk. This is where the nerve impulse is picked up and brought to the brain for interpretation. The accessory organs are the orbits, eyelids, conjunctivas, lacrimal apparatus, and extrinsic eye muscles, all of which are protective for the eye.
66In Summary (cont.)31.7 The cornea, lens, and fluids focus light on the retina. The retina converts the image into nerve impulses, which are transmitted by the optic nerve to the brain for interpretation.31.8 Eye safety and injury prevention includes, but is not limited to, adequate lighting and availability of hand rails, keeping personal and sharp items out of reach of children, wearing of safety goggles when operating power equipment and using chemicals, and not mixing cleaning agents.
67In Summary (cont.)31.9 Changes in the aging eye include, but are not limited to, diminishing fat tissue, decreased tear production, thinner and dryer conjunctiva, brown spots in the sclera, changes in the iris resulting in smaller pupil, lens becoming denser and more rigid, as well as lens and retinal changes causing fuzziness of vision and difficulty distinguishing colors.31.10 Ophthalmologists (M.D.), optometrists (O.D.), and opticians are all professionals who deal with eye and vision health.
68In Summary (cont.)31.11 All treatments for eye problems include use of sterile technique and extreme caution to protect the delicate tissues of the eye. Eye irrigations and medication installations are common treatments. Instruction on these techniques will take place in the Drug Administration chapter.
69In Summary (cont.)31.12 Common diseases and disorders of the eye include amblyopia, astigmatism, cataracts, conjunctivitis, hyperopia, myopia and presbyopia. More detailed information on the signs, symptoms, and treatments for these conditions, as well as other common eye disorders, is found in the Pathophysiology section of this chapter, directly after the A&P section on the eye.
70In Summary (cont.)31.13 There are three parts to the ear. The external ear includes the auricle or pinna and external auditory canal to the tympanic membrane. The middle ear begins at the tympanic membrane and ends at the oval window and includes the ear ossicles. The inner ear is composed of the labyrinth and contains the organ of Corti as well as perilymph and endolymph, the fluids of hearing.31.14 The semicircular canals and vestibule in the inner ear function in the equilibrium and balance of the body, sending impulses to the vestibular nerves, which transmit information to the cerebrum for interpretation.
71In Summary (cont.)31.15 The outer ear collects sound waves and channels them to the tympanic membrane, which vibrates. The vibrations are amplified by the ear ossicles and enter the inner ear and cochlea. The movements of the hairs in the cochlea trigger nerve impulses that are transmitted by the auditory nerve to the brain.31.16 Aging causes the eardrum to shrink. The joints between the ossicles degenerate so there is less freedom of movement, which causes decrease in hearing acuity.
72In Summary (cont.)31.17 Conductive hearing loss is the result of sound wave transmission interruption, as with cerumen impaction and tumors or infections. Sensorineural hearing loss is the result of nerve damage so that the brain cannot perceive sounds waves as sound.31.18 Ear treatments depend on the condition being treated, but may include ear irrigation and medication installation as well as hearing aids and/or surgery for hearing loss.
73In Summary (cont.)31.19 Preventative ear care includes, but is not limited to, routine hearing exams; avoiding the insertion of small items into the ear canal; and using care when using cotton swabs. Ear protection should be used when exposed to loud or prolonged noise. Use medications such as ear drops properly and watch for signs of ear or hearing problems.
74In Summary (cont.)31.20 The pathophysiology section on ear and hearing diseases and conditions is found at the end of the A&P section for the ear. Signs, symptoms, and treatments of cerumen impaction, hearing loss, Ménière's disease, otitis, otosclerosis, and other common problems are outlined in this section.
75End of Chapter 31Every closed eye is not sleeping, and every open eye is not seeing.~ Bill Cosby