1. Visual & Auditory Systems

2. Introduction Five main senses of body system: sight, hearing, touch, smell, taste, Two senses that can change life dramatically: seeing and hearing

3. The Eyes Images translate into impulses that create lasting memories in the mind Three different levels of eye specialists: Opticians make lenses Optometrists perform eye exams Ophthalmologists are medical doctors

4. Anatomy of the Eye Eyebrows shade eyes from light, particles and sweat Eyelashes catch debris, keep eyes moist, shade the eyes Orbit: bony socket that holds the eye Eye position: 100 degrees peripheral vision Eyelids: Four layers (outer skin, muscles, connective tissue, conjunctiva) Layers allow the eyes to open and close

5. Anatomy of the Eye (Continued) Conjunctiva: thin transparent layer, mucous membrane, covers eyelids and sclera Lacrimal gland: in orbit, secretes tear into eye; has ducts to nasal cavity

6. Anatomy of the Eye (Continued) Cornea: transparent cover allows light into the eye Connective tissue covered with thin epithelial layer No blood vessels—nourished by aqueous humor (tissue fluid) and oxygen Nerve fibers sensitive to pain

7. Anatomy of the Eye (Continued) Sclera: Attached to cornea; wraps around back of eyeball White portion of eye: many fibers and muscles with opening for optic nerve Optic nerve sends images to brain for interpretation Iris: colored part of eye to filter light Vitreous humor: nourishes and cleanses eye

8. Anatomy of the Eye (Continued)

9. Eye Muscles and Direction of Movement Six muscles responsible for eye movements

10. Anatomy of the Eye (Continued) Pupil: Dilates (mydriasis) when focusing on distant figure or darkness Constricts (miosis) in extreme light Aqueous humor provides the nutrients and oxygen to maintain lens and cornea Accumulates; must be released to maintain pressure Canal of Schlemm: ducts used to release aqueous humor

11. Anatomy of the Eye (Continued) Retina contains rods and cones responsible for vision Rods: sight in dim light; produce black and white images Cones: detect color Rods and cones signals sent through optic nerve to brain Occipital lobe—visual interpretation How the Eye Works - Video clip

12. Rods and Cones

13. Conditions That Affect the Eye New developments/treatments: Laser surgery-correct vision Lens implantation—for blindness Conditions: Glaucoma Conjunctivitis Congestion of eye Viral and bacterial infections

14. Glaucoma Pressure within the eyes is higher than normal (increased ocular pressure [IOP]) Two causes: overproduction of aqueous humor; blocked ducts that drain excess aqueous humor Left untreated, causes blindness Types of glaucoma include primary, acute congestive, and chronic simple

15. Glaucoma

16. Conjunctivitis “Pink eye” Common in daycare centers; contagious Acute inflammation of the conjunctiva Causes: viral, bacterial, fungal, allergies Symptoms: inflammation, itching, burning, white mucus

17. Conjuctivitis

18. Color Blindness Cones: responsible for color perception Three photopigments—identifies three colors—green, blue, red Missing/abnormal pigment: difficult or impossible to detect colors No treatment available

19. Color Blindness Tests

22. Blindness Causes: Accidents Cataracts Macular Degeneration Diabetic Retinopathy Glaucoma Corneal transplant—may correct blindness

23. Ophthalmic Agents Ophthalmic agents aimed at controlling glaucoma, infection, inflammation, or manipulating dilation Dosage forms: drops, suspensions, ointments, medicated disks, corrective lenses

24. General Information Eye solutions—keep sterile—foreign objects instilled into eyes can cause damage or infection Patients avoid touching medication; will cause contamination Do not instill while wearing contact lenses

25. The Ear Human ear responsible for hearing, balance, equilibrium, communication skills Composed of three sections: external, middle, inner

26. The Ear

27. External Ear External ear—auricle; composed of cartilage and skin; entrance for sound waves Auditory canal: about 1 inch long; leads to tympanic membrane (eardrum) Two major functions of tympanic membrane: protection of middle ear from foreign objects; transmission of sounds to middle ear

28. External Ear Sounds transmitted by vibrations Cerumen: wax substance produced by glands

29. Middle Ear Vibration carried to middle ear Cavity contains bony structures (ossicles): malleus, incus, stapes Ossicles connected to each other

30. Middle Ear Eustachian tube: Leads to nasopharynx Equalizes pressure between outside and inside atmosphere

31. Eustachian Tube

32. Inner Ear Stapes continues transfer of sound to inner ear Fluid-filled cavity—labyrinth; comprise many components that process and transmit audible sounds via nerve impulses to brain

33. Inner Ear (Continued) Three main areas of the inner ear include: Cochlea Vestibule Semicircular canal How the Ear works Video

34. Conditions Affecting the Ear Various conditions affect quality of hearing: infections, ear wax accumulation, damage to eardrum, genetic defects Deafness—factors other than genetic abnormalities—age, inflicted damage Loud noises break hairlike structures in middle ear; do not regenerate No medication available—hearing aids

35. Otitis Media Infection of the middle ear associated with inflammation of eustachian tube Sore throat—can lead to middle ear infection—often seen in children Treatment: antiinfectives Reoccurring infections—insertion of small tubes by physicians to drain middle ear

37. Cerumen Buildup and Ototoxicity Excessive wax builds up or dries—impedes hearing quality Doctor removes wax buildup Ototoxicity caused by some drugs Tinnitus—buzzing or ringing in ears—if untreated leads to permanent ear damage Balance may also be affected

38. Otic Preparations Bacterial infections treated with bactericidal or bacteriostatic preparations All ear agents—combinations—antibiotics, steroids, ear wax removers