2. Healthy Eyes and Ears (2:04) Click here to launch video Click here to download print activity

3. Your Eyes The lacrimal gland secretes tears into the eye through ducts. Tears keep the surface of the eyeball moist and clear of foreign particles.

4. Parts of the Eye sclera optic nerve retina cornea iris pupil lens

5. Parts of the Eye The sclera is composed of tough, fibrous tissue. Sclera The white part of the eye

6. Parts of the Eye At the front of the eye rests the cornea. Cornea A transparent tissue that bends and focuses light before it enters the lens

7. Parts of the Eye The retina contains millions of light-sensitive cells called rods and cones, each named for its basic shape. Retina The inner layer of the eye wall

8. Parts of the Eye Rods are light sensitive cells that allow us to see in dim light. Cones are light sensitive cells that allow us to see in bright light and in color.

9. Parts of the Eye Sclera Cornea Choroid Iris Pupil Protects the inner eye and supports and shapes the eyeball Bends and focuses light before it enters the lens Lines the inside of the sclera Contracts and dilates the pupil Regulates the amount of light that reaches the inner eye

10. Parts of the Eye Retina Optic Nerve Lens Aqueous Humor Vitreous Humor Contains light-sensitive cells Transmits nerve impulses to the brain Helps refine the focus of images on the retina Provides nutrients to the eye Helps the eyeball stay firm and keeps the retina in place

11. Vision Eye doctors refer to clear, sharp, normal vision as 20/20 vision. Other components of vision include eye coordination, peripheral or side vision, and depth perception.

12. Vision Nearsightedness, or Myopia Farsightedness, or Hyperopia Astigmatism Strabismus Detached Retina The inability to see distant objects clearly The inability see close objects clearly Blurred vision Eyes off-center, turned inward or outward Blurred vision or bright flashes of light Common Vision Disorders

13. Vision Infections and Viruses Glaucoma Cataracts Macular Degeneration Swelling, irritation, blurred vision, change in sclera color Cloudy, impaired vision, can cause permanent damage. Pressure in eye is too high. Foggy vision Vision loss Common Vision Problems

14. Keeping Your Eyes Healthy Tips for Keeping Your Eyes Healthy Follow a well- balanced eating plan. Protect your eyes. Rest your eyes regularly. Get regular eye exams.

15. Dominant Eye Test

17. Blind Spot Test

18. Your Ears The inner, middle, and outer ear work together so you can hear. The ear has two functions: hearing and balance.

19. Your Ears

20. Parts of The Outer EarFunction Auricle External Auditory Canal Eardrum Channels sound waves into the external auditory canal Channels sound waves from the auricle to the eardrum Acts as a barrier between the outer and middle ear

21. Your Ears Parts of The Inner EarFunction Auditory Ossicles Eustachian Tube Connect the eardrum to the inner ear Connects the middle ear to the throat

22. Your Ears The auditory ossicles lie in the middle ear directly behind the eardrum. Auditory ossicles Three small bones linked together that connect the eardrum to the inner ear

23. Your Ears The labyrinth consists of a network of curved and spiral passages in the inner ear. Labyrinth The inner ear

24. Your Ears The labyrinth has three main parts. The cochlea, a spiral-shaped canal, is the area of hearing in the inner ear. The vestibule and the semicircular canals are where balance is controlled.

25. Hearing and Balance Receptors cells within the cochlea send nerve impulses to the brain, where sound is interpreted. Receptor cells in the vestibule and the semicircular canals send nerve impulses to the brain, and the brain makes adjustments to maintain balance.

26. Keeping Your Ears Healthy Tips for Keeping Your Ears Healthy Wear a hat that covers both the auricles and the earlobes in cold weather.  Wear protective gear, such as a batting helmet, when playing sports.  Keep foreign objects, including cotton- tipped swabs, out of the ear canal. 

27. Preventing Hearing Loss Exposure to loud noises can lead to temporary and sometimes permanent hearing loss, or deafness, over time.

28. Conductive Hearing Loss In conductive hearing loss, sound waves are not passed from the outer ear to the inner ear, usually because of a blockage or injury to the inner ear.

29. Sensorineural Hearing Loss Sensorineural hearing loss may result from a birth defect, exposure to noise, growing older, and medication problems.

30. Sensorineural Hearing Loss To prevent tinnitus, avoid loud music, wear earplugs in noisy environments, and at loud concerts or sporting events. Tinnitus A condition in which a ringing, buzzing, whistling, roaring, hissing, or other sound is heard in the ear in the absence of external sound

31. Quick Review 1.What are the types of hearing loss? 2.Identify the structures of the eye. 3.What are some of the problems of the eye? 4.What are some of the problems of the ear?