1. Hearing: How do we hear?

2. Hearing: The Nature of Sound Module 9: Sensation

3. Sound Sound, like light, comes in waves Sound is vibration Features of sound include: –Pitch –Hertz –decibels

4. Pitch A sound’s highness or lowness Dependent on the frequency of the sound wave Is measured as hertz (Hz)

5. Hertz (Hz) A measure of the number of sound wave peaks per second; measures “frequency” Determines the pitch of the sound Human hearing goes from 20 Hz to 20,000 Hz

6. Decibel (dB) A measure of the height of the sound wave Determines the loudness of the sound Sometimes called amplitude

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

9. Hertz (Hz) A measure of the number of sound wave peaks per second; measures “frequency” Determines the pitch of the sound Human hearing goes from 20 Hz to 20,000 Hz

10. Decibel (dB) A measure of the height of the sound wave Determines the loudness of the sound Sometimes called amplitude

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

13. Hearing: The Structure of the Auditory System Module 9: Sensation

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

15. PINNA It collects sound and directs it into the outer ear canal. The visible part of the outer ear.

16. Parts of the Ear – Sound Waves

17. The opening through which sound waves travel as they move into the ear for processing Ends at the eardrum Auditory Canal

18. Parts of the Ear – Auditory Canal

19. THE MIDDLE EAR

20. Eardrum Also called the tympanic membrane. A thin membrane that vibrates when sound waves reach it. it transfers sound vibration from the air to the tiny bones of the middle ear Can be damaged by objects in the ear or exceptionally loud noises

22. Parts of the Ear – Tympanic Membrane

23. Bones of the middle ear - Ossicles Three 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 Ear - Occicles

26. Oval Window The point on the surface of the cochlea which receives the sound vibration from the bones of the middle ear (ossicles) As the oval window vibrates, the fluid in the cochlea vibrates.

27. Parts of the Ear – Oval Window

28. 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

29. Parts of the Ear - Cochlea

31. Hair Cells The receptor cells for hearing in the cochlea that change sound vibrations into neural impulses Transduction!

32. Parts of the Ear - Hair Cells

33. Parts of the Ear – Oval Window

34. Auditory Nerve The nerve that carries sound information from the ears to the temporal lobes of the brain

35. Parts of the Ear – Auditory Nerve

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

37. Divisions of the Ear

40. Hearing Sound comes into the ear Goes through the ear canal to the eardrum Ear drum changes sound into vibrations Vibrations go through middle ear to the inner ear –

41. Hearing Where vibrations are changed into neural impulses so that the brain can read / interpret the sound – What are the receptors cells for hearing?

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

43. Hearing: Sound Localization Module 9: Sensation

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

45. Localization of Sound

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

47. Another sense in your ears? Is there another sense in your ear? Time to do an experiment – let’s find out… out to the hallway we go!!!!

48. Vestibular Sense The system for sensing body orientation and balance Relies on fluid in the semicircular canals of the inner ear Spinning in circles disrupts the fluid.

49. Parts of the Ear – Semicircular Canals

51. Semicircular canal What situations will affect the semicircular canal

52. Let’s Process Get a scrap 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