1. Hearing: How do we hear?

2. Our Essential Questions What are the major parts of the ear? How does the ear translate sound into neural impulses?

3. Sound What part of the brain? Sound comes in waves Vibration

4. Pitch A sound’s highness or lowness Dependent on the frequency of the sound wave – the more “waves per second” the higher the frequency or pitch Measured as hertz (Hz)

6. Hertz (Hz) Measure of the number of sound wave peaks per second; measures frequency Determines the pitch of the sound Human hearing: 20 Hz - 20,000 Hz

7. What pitch can you hear? http://journal.plasticmind.com/ears/mosquito-tone-or- how-to-tell-youre-a-youngun/

8. Decibel (dB) A measure of the height of the sound wave Loudness of the sound Amplitude

9. What are good sounds versus bad? What volume do you think is okay? Not good, not bad? Bad?

11. Hearing: The Structure of the Auditory System

12. Divisions of the Ear Ear’s structure can be divided into: –The outer ear –The middle ear –The inner ear

13. Break It Down Sound waves are collected in the outer ear, amplified in the middle ear, and transduced, in the inner ear.

14. Divisions of the Ear The outer ear collects sound

15. Parts of the Outer Ear – Pinna The visible part of the outer ear. collects sound and directs it to auditory canal

16. Parts of the Ear – Sound Waves

17. The opening, tunnel that sound waves travel through Ends at the eardrum Parts of the Outer Ear – Auditory Canal

19. Divisions of the Ear The middle ear amplifies sound

20. Parts of the Middle Ear - Eardrum AKA tympanic membrane Thin membrane that vibrates when sound waves reach it Transfers sound vibration from the air to the tiny bones of the middle ear Damage?

22. Parts of the Middle Ear – Tympanic Membrane

23. Parts of the Middle Ear - Ossicles 3 tiny bones that transfer sound waves from the eardrum to the cochlea Hammer, anvil and stirrup –Fun fact: the stirrup is the smallest bone in the human body – only.25 cm

25. Parts of the Middle Ear - Occicles

26. Divisions of the Ear The inner ear transduces sound

27. Parts of the Inner Ear - Oval Window Intersection of the middle ear with the inner ear Touches the stirrup As the oval window vibrates, the fluid in the cochlea vibrates From eardrum  oval window, sound is amplified 20 times

28. Parts of the Inner Ear – Oval Window

29. Parts of the Inner Ear - Cochlea A hearing organ where sound waves are changed into neural impulses (transduction) The major organ of hearing Filled with fluid; a snail shaped body tube

30. Parts of the Ear - Cochlea

32. Parts of the Inner Ear - Hair Cells The receptor cells …what do they do? Transduction!

33. Parts of the Inner Ear - Hair Cells

34. Parts of the Inner Ear - Auditory Nerve carries sound information from the ears to the brain Like the optic nerve

35. Parts of the Inner Ear – Auditory Nerve

36. Hearing - Review Sound is collected by pinna Goes through the ear canal to the eardrum Eardrum changes sound  vibrations Vibrations go from middle ear  inner ear via oval window

37. Hearing - Review Here vibrations  neural impulses so that the brain can read / interpret the sound What are the receptors cells for hearing?

38. Problems with hearing Conduction deafness (middle ear damage) Nerve deafness (hair cell or auditory nerve damage)

39. Localization of Sound Locating where sound is originating from Done through two cues: –Which ear hears the sound first? –Which ear hears the sound louder?

40. Localization of Sound

41. YOU Break It Down This Time Sound waves are ______ in the outer ear, _______ in the middle ear, and ________, in the inner ear.

42. Is there another sense in your ear?

43. Vestibular Sense body orientation and balance Receptor cells: semicircular canals, hair cells in inner ear Parietal lobes Motion sickness = overstimulation

44. Parts of the Ear – Semicircular Canals

46. Semicircular canal What situations will affect the semicircular canal?

47. Let’s Process Get a piece of paper Trace the ear Label as much as you can by your self – 60 seconds Get with a partner – fill in the rest Together, briefly describe how sound is changed into neural impulses