The Senses: The Sights and Sounds

1. 11 The Senses: The Sights and Sounds

2. Multimedia Directory Slide 31 Eye Anatomy Animation Slide 41 Macular Degeneration Video Slide 54 Eye Assessment Video Slide 62 Middle Ear Animation Slide 63 Adolescent Ear Animation Slide 64 Child's Ear Animation Slide 65 Otoscopic Exam on Toddler Video Slide 66 Tympanometry Video Slide 75 Tympanic Membrane Temperature Video Slide 93 Heat Therapy Video Slide 95 Cold Therapy Video Slide 100 Pain Perception Video Slide 101 Selected Pain Scales Video

3. Multimedia Directory Slide 112 Cataracts Video Slide 119 Conjunctivitis Video Slide 128 Administering Ophthalmic Medications Video Slide 130 Otoscopic Exams Video Slide 133 Otitis Media Video Slide 139 Ophthalmic Drops Video Slide 140 Otic Drops Video Slide 141 Ophthalmic Medication Video Slide 142 Eye Irrigation Video Slide 144 Otic Medication Video Slide 145 Ear Irrigation Video Slide 155 Audiology Video Slide 156 Audiologists Video

4. Multimedia Directory Slide 157 Ophthalmologists and Opticians Video

5. Introduction • All of input from environment must be taken in by senses and interpreted by brain so you can understand and appreciate experience • Senses that gather sensory input are also protective in nature and need to be highly integrated with quick response nervous system for our survival

6. Learning Objectives • Differentiate between general and special senses • Describe the internal and external anatomy and functions of the eye • Describe the internal and external anatomy and functions of the ear • Discuss the process involved with the senses of taste, smell, and touch

7. Learning Objectives • Contrast the types of pain and the pain response • Explain several common disorders of the eyes, ears, and senses

8. Pronunciation Guide amblyopia anesthesia aqueous humor auricle cataract cerumen ceruminous glands choroid ciliary muscles cochlea (am blee OH pee ah) (an ess THEE zee ah) (AY kwee us HYOO mer) (AW rih kul) (KAT ah rakt) (seh ROO men) (seh ROO men us) (KOH royd) (SILL ee air ee) (KOHK lee ah)

9. Pronunciation Guide conjunctiva conjunctivitis endolymph Eustachian tubes external auditory meatus glaucoma gustatory sense hyperopia incus iris (KON junk TIE vah) (kon JUNK tih VYE tis) (EN doe limf) (yoo STAY she ehn) (AW dih tor ee mee AY tus) (glaw KOH mah) (GUSS ta tore ee) (HIGH per OH pee ah) (ING kuss) (EYE riss)

10. Pronunciation Guide labyrinth labyrinthitis lacrimal apparatus malleus Ménière's disease myopia nyctalopia ossicle otitis media perilymph (LAB ih rinth) (LAB in rinn THYE tiss) (LAK rim al app ah RA tus) (MALL ee us) (MAIN ee AIRZ) (my OH pee ah) (nik tah LOH pee ah (AH sih kel) (oh TYE tiss ME dee ah) (per ih LIMF)

11. Pronunciation Guide photopigments pinna presbycusis presbyopia pupil retina sclera stapes strabismus tactile corpuscles (FOE toe pig ments) (PINN ah) (prez be KYOO sus) (PRESS bee OH pee ah) (PYOO pill) (RETT in ah) (SKLAIR ah) (STAY peez) (strah BIZ mus) (KOR pus elz)

12. Pronunciation Guide tinnitus tympanic membrane vestibule chamber vestibulocochlear vitreous humor (tinn EYE tus) (tihm PAN ick) (VESS tih byool) (VESS tih byoo loh KOHK lee are) (VITT ree us HYOO mer)

13. The Different Senses • Our senses allow us to experience all aspects of our journey, allowing us to see, hear, smell, taste, feel the world around us

14. The Different Senses • Senses enable us to monitor and detect changes in environment, sending this information to brain via sensory (afferent) neurons • Brain interprets information and makes appropriate motor (efferent) response

15. The Different Senses • Senses of sight, hearing and balance, sound, taste, and smell referred to as special senses • Other senses scattered throughout body referred to as general senses; sensation of heat, cold, pain, nausea, hunger, thirst, and pressure of touch

16. The Different Senses • Cutaneous senses include receptors of skin (touch, heat, cold, and pain) • Visceral senses include nausea, hunger, thirst, and need to urinate and defecate • One controversial sense is extrasensory perception, meaning outside normal sensory perception; there is still debate over whether this sense exists

17. Sense of Sight • Eye has many similarities to a camera; light rays from image you view pass through pupil, and then through lens, where they are focused by retina • Iris allows right amount of light to enter the eye for proper focusing

18. External Structures of Eye • Lacrimal glands secrete tears to help keep eye clean • Orbit (orbital cavity): cone-shaped cavity formed by skull that houses and protects eyeball; cavity is padded with fatty tissue that acts as cushion to prevent injury

19. External Structures of Eye • Six short muscles connect eyeball to orbit, and allow rotary movement so you can see in all directions

20. External Structures of Eye • Eyelids close over eye to protect it from intense light, foreign particles, or impact injury • Eyelashes in eyelid help to prevent large particles from entering eye • Eyelids contain sebaceous glands that secrete sebum to keep eyelids soft, pliable, and slightly sticky to trap particles

21. External Structures of Eye • Conjunctiva is membrane over surface of eyeball that acts as protective covering for exposed surface • Lacrimal apparatus produces and stores tears and contains lacrimal gland and its corresponding ducts • Lacrimal gland produces tears, spread by blinking, for cleaning and lubrication; tears act as antiseptic

22. Figure 11-1External and lacrimal structures of the eye.

23. Internal Structures of Eye • Globe-shaped eyeball is organ of vision and is separated into two chambers of fluid that help to protect eye • "Fluids of the eye" are called humors • Aqueous humor: "watery" and bathes iris, pupil, lens and fills anterior and posterior chambers • Vitreous humor: clear jellylike fluid that occupies entire eye cavity behind lens

24. Eye Layers • Sclera • Outermost layer and is tough, fibrous tissue that serves as protective shield • Contains cornea, which is transparent to allow light to pass through and curved to bend entering light to focus it on retina

25. Eye Layers • Choroid • Highly vascularized and pigmented region that provides nourishment to eye • Middle layer, containing iris and pupil • Iris is colored portion of eye

26. Eye Layers • Choroid • Iris is sphincter that controls opening (pupil) where light passes into eye • In low light, sphincter relaxes, allowing pupil to dilate so more light can enter

27. Eye Layers • Retina • Innermost layer; contains nerve endings that receive and interpret rays of light • Lens: located behind iris and pupil is elastic, discshaped, biconvex crystalline structure

28. Eye Layers • Retina • When light enters eye, it is refracted by lens • Light rays enter eye and pass through conjunctival membrane, cornea, aqueous humor, pupil, lens, vitreous humor and are focused on retina

29. Figure 11-2The internal structures of the eye.

30. Table 11-1 Structures and Functions of the Eye

31. Eye Anatomy Animation Click on the screenshot to view an animation of the eye anatomy. The animation may take a moment before playing. Back to Directory

32. Pathology Connection:Disorders of the Eyes • Stye (hordeolum): abscess that forms at base of eyelash due to infection of sebaceous gland. • Result of bacterial infections • Red, swollen, painful; resemble acne pimples.

33. Pathology Connection:Disorders of the Eyes • Conjunctivitis: inflammation of membrane that lines eye • Sometimes called pinkeye because it is characterized by red, swollen eyes

34. Pathology Connection:Disorders of the Eyes • Conjunctivitis: inflammation of membrane that lines eye • Possible causes • Irritants (fumes or onions) • Pathogens (viruses or bacteria); examples: Staphylococcus aureus, acute infection; Chlamydia trachomatis, tends to cause more chronic infection (trachoma)

35. Pathology Connection:Disorders of the Eyes • Conjunctivitis: inflammation of membrane that lines eye • Viral and bacterial conjunctivitis are highly contagious

36. Pathology Connection:Disorders of the Eyes • Cataract: clouding of lens • Possible causes • Congenital defects • Trauma • Aging • Increased exposure to sunlight may also speed up the development of cataracts

37. Pathology Connection:Disorders of the Eyes • Cataract: clouding of lens • Untreated, can lead to blindness • Typical treatment: surgery; cataract surgery was one of earliest recorded surgical procedures, dating back to ancient Greece

38. Pathology Connection:Disorders of the Eyes • Glaucoma: increased pressure in fluid of eye; interferes with optic nerve function • Vision gradually deteriorates • Peripheral vision is reduced first • Eventually, tunnel vision develops • Blindness can eventually develop

39. Pathology Connection:Disorders of the Eyes • Glaucoma • Epidemiology • Occurs in 20% of adults over age 40 • Accounts for 15% of blindness in America • Can be easily diagnosed • Treatments include medication and surgery

40. Pathology Connection:Disorders of the Eyes • Macular degeneration: condition that causes loss of central vision (peripheral vision is unaffected) • Two forms • Atrophic (dry): has no cure • Exudative (hemorrhagic): can be improved slightly with argon laser therapy

41. Macular Degeneration Video Click on the screenshot to view a video on the topic of macular degeneration. Back to Directory

42. Pathology Connection:Disorders of the Eyes • Retinopathy: irreversible damage to retina • Can be caused by systemic diseases like hypertension or diabetes mellitus • Can result in vision impairment or blindness

43. Pathology Connection:Disorders of the Eyes • Defects that impair vision • Hyperopia (farsightedness): when eye cannot focus properly on nearby objects; glasses using convex lenses used to correct hyperopia

44. Pathology Connection:Disorders of the Eyes • Defects that impair vision • Presbyopia: farsightedness that occurs with age, usually between 40 and 45 years; lens becomes stiff and yellowish • Sensitive to glare that can impair nighttime driving abilities; corrective lenses (bifocals) used to treat presbyopia

45. Pathology Connection:Disorders of the Eyes • Defects that impair vision • Myopia (nearsightedness): causes objects at distance to appear blurred • Glasses with concave lenses correct myopia by refocusing focal point backward and onto retina

46. Pathology Connection:Disorders of the Eyes • Defects that impair vision • Amblyopia (lazy eye) • Occurs in childhood • Causes poor vision in one eye because one eye does more work than the other • Diplopia: brain perceives two images; person affected has double vision • May be result of nonocular disease • Eye patch, corrective lenses, or surgery

47. Pathology Connection:Disorders of the Eyes • Defects that impair vision • Strabismus: one eye misaligned due to inability of muscles in one eye to coordinate movement with other eye • Children affected due to congenital defect • Nyctalopia: degeneration of retina; difficulty seeing at night or in dim light • Often caused by vitamin A deficiency; vitamin A needed to make photopigments in rod cells

48. Pathology Connection:Disorders of the Eyes • Corrective vision options • Eyeglasses • Contact lenses • Refractive eye surgery; radial keratotomy (RK) • In situ keratomileusis (LASIK) surgery

49. Pathology Connection:Disorders of the Eyes • Defects that impair vision • Red-green color blindness • Inability to distinguish between colors red and green • Caused by genetic defect carried on X chromosome; causes more men to get disorder • Diagnosed with colored figures that require patients to distinguish between various colors

50. Figure 11-3A comparison on near- and farsightedness.