1. Sound: The Ear

2. Introduction Ears are sense organs that respond to sound. The ear’s structure is designed to receive the sound waves… Your ear converts sound waves into electrical signals that your brain interprets.

3. Parts of the Ear

5. OBJECTIVES Trace the path of sound through the ear to the brain. Describe how the parts of the ear function. Label parts of the ear.

6. IN QUESTION There are three things necessary in order for humans to hear a sound. Can you name them? Something to make the sound A medium to carry the sound Something to detect the sound

7. The Outer Ear

9. INTRODUCTION Part of the job of the outer ear is to help protect the rest of the ear. Earwax plays a big part in this protection. Your body makes earwax to keep things out of your ears that might be harmful to the inner ear parts. The wax is called cerumen. (suh – roo – mun)

10. The Ear Drum

11. The Middle Ear

13. Inner Ear Bones

15. The Inner Ear

17. INTRODUCTION The inner ear also has another job that has nothing to do with hearing. The inner ear helps you maintain balance.

18. INTRODUCTION After you ride a roller coaster, you may feel dizzy. The tiny hairs inside the fluid filled canals of the inner ear’s balance center send mixed up signals to the brain, tricking the brain into thinking you are spinning.

19. The Cochlea

20. Hair Cells

21. Analogy for Inside the Cochlea

22. NOTES Ear divided into 3 sections: outer ear, middle ear, inner ear. Outer ear, sound waves focused by pinna down ear canal to eardrum. Sound waves make eardrum vibrate. Middle ear, vibrations amplified by 3 bones: hammer, anvil, stirrup. Inner ear, stirrup transfers vibrations to cochlea. Vibrations activate hair cells inside cochlea, sends electrical signals to brain along auditory nerve. Brain interprets signals as sound.

23. NOTES

24. Outer ear produces ear wax to help protect inner ear parts. Inner ear responsible for your bodies sense of balance. When irritated, hairs inside balance center send mixed-up signals to brain, this causes dizziness.

25. COPY TO HANDOUT

26. A Final Look!

27. OUT QUESTION Why do you think ear wax is sticky?