1. AP Hearing & Other Senses
Audition: The sense or act of hearing.

2. The Ear
OBJECTIVE 12| Describe the three regions of the ear, and outline the series of events that triggers the electrical impulses sent to the brain.

3. Two bundles of aging outer hair cells showing severe degeneration
Two bundles of aging outer hair cells showing severe degeneration. The outer hair cells are responsible for fine tuning and amplifying the sounds that are detected by the inner hair cells. This age-related degeneration of hair cells is responsible for the hearing loss often associated with aging.

4. The Ear Outer Ear: Pinna. Collects sounds.
Middle Ear: Chamber between eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window.
Inner Ear: Innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.

5. How do we perceive differences in pitch?
There are two theories……..

6. Theories of Audition
Helmholtz Place Theory suggests that sound frequencies stimulate the basilar membrane at specific places resulting in perceived pitch.
OBJECTIVE 13| Contrast place and frequency theories, and explain how they help us to understand pitch perception.

7. Theories of Audition
Frequency Theory states that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch.
Auditory Nerve
Action Potentials
Sound
Frequency
200 Hz
100 Hz

8. Hearing Loss
Conduction Hearing Loss: Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.
Sensorineural Hearing Loss: Hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerve, also called nerve deafness.
OBJECTIVE 15| Contrast two types of hearing loss, and describe some of their causes.

9. Hearing Deficits
Older people tend to hear low frequencies well but suffer hearing loss when listening for high frequencies.

10. Deaf Culture
Cochlear implants are electronic devices that enable the brain to hear sounds.
OBJECTIVE 16| Describe how cochlear implants function, and explain why Deaf culture advocates object to these devices. Where these implants are pertinent for hearing parents with deaf children, deaf culture advocate not using them especially on children deafened before learning to speak.
Wolfgang Gstottner. (2004) American
Scientist, Vol. 92, Number 5. (p. 437)
EG Images/ J.S. Wilson ©
Deaf Musician
Cochlear Implant

11. Why do we have two ears?

12. Localization of Sounds
Because we have two ears, sounds that reach one ear faster than the other ear cause us to localize the sound.
OBJECTIVE 14| Describe how we pinpoint sounds.

13. Smell and Taste

14. Was I born to love peanut butter & jelly?
What is the bigger question here?
Nature versus Nurture

15. Taste: Gustation
Traditionally, taste sensations consisted of sweet, salty, sour, and bitter tastes. Recently, receptors for a fifth taste have been discovered called “Umami”.
OBJECTIVE 19| Describe the sense of taste, and explain the principle of sensory interaction.
Sweet
Sour
Salty
Bitter
Umami
Meaty/cheesy

16. So….Was I born to love peanut butter & jelly?
Lets take a look at the Nature perspective first.

17. How do we taste? What is the central muscle involved in taste?
Taste (and smell) are chemical senses.
What is the central muscle involved in taste?

18. Tongue

19. Papillae Those bumps on our tongue are called Papillae.
Papillae help grip food while your teeth are chewing. They also have another special job - they contain your taste buds

20. Transduction of Taste Surface of the tongue
chemicals, which are the stimuli for taste, break down into molecules
molecules mix with saliva an run into narrow trenches on the surface of the tongue
molecules then stimulate the taste buds
Gustation: the process of tasting

21. SEM Taste bud on fungiform papilla, close-up Scanning electron micrograph of close-up of a taste bud on a fungiform papilla on the tongue, computer-coloured red./pink.

22. Transduction of Taste Taste buds shaped like miniature onions
receptors for taste
chemicals dissolved in saliva activate taste buds
produce nerve impulses that reach areas of the brain’s parietal lobe
brain transforms impulses into sensations of taste

23. The Tongue

24. Gustatory Pathway
Figure 15.2

25. Sensory Interaction
When one sense affects another sense, sensory interaction takes place. So, the taste of strawberry interacts with its smell and its texture on the tongue to produce flavor. Taste is 80% smell.

26. Smell: Olfaction
Like taste, smell is a chemical sense. Odorants enter the nasal cavity to stimulate 5 million receptors to sense smell. Unlike taste, there are many different forms of smell.
OBJECTIVE 20| Describe the sense of smell and explain why specific odors so easily trigger memories.

27. Transduction of Olfaction
Stimulus
we smell volatile substances
volatile substances are released molecules in the air at room temperature
example: skunk spray, perfumes, warm brownies; not glass or steel
4 Primary Odors
acid  sour
burnt
fragrant  sweet
caprylic  rancid, rotten
Not in text

28. Transduction of Olfaction
Olfactory cells
receptors for smell are located in a I-inch-square patches of tissue in the uppermost part of the nasal passages.
olfactory cells are covered in mucus
which volatile molecules dissolve and stimulate the cells
the cells trigger nerve impulses that travel to the brain
which interprets the impulses as different smells (some 10,000 or so)
Sensory adaptation don’t smell own perfume, sweat, …

29. Cilia: Nose Hairs

30. Sense of Smell
Figure 15.3

31. Smell and Memories
The brain region for smell (in red) is closely connected with the brain regions involved with memory (limbic system). That is why strong memories are made through the sense of smell.

32. Age, Gender, and Smell
Ability to identify smell peaks during early adulthood, but steadily declines after that. Women are better at detecting odors than men.

33. Gender related odors
Can you smell the difference between?

34. So can we smell the difference?
Well….yes and no.
Pheromones
Chemical messengers that are picked up through our sense of smell.
Founded in the early 1930’s by studying silkworms.
Jury is still out on whether they exist in humans. Best evidence we have comes out of the university of Chicago.

35. Functions of Olfaction
to intensify the taste of food
to warn of potentially dangerous foods
elicit strong memories; emotional feelings

36. Let us not forget about Nurture

38. Shop at the local Chinese Walmart

39. Somesthetic Senses Soma  body Esthetic  feeling
Touch Kinesthetic Vestibular

40. Skin Senses
The sense of touch is a mix of four distinct skin senses—pressure, temperature (warmth & cold), and pain.
OBJECTIVE 17| Describe the sense of touch. “Touch is both the alpha and omega of affection” (James, 1890).
Bruce Ayers/ Stone/ Getty Images

41. Skin Senses
Only pressure has identifiable receptors. All other skin sensations are variations of pressure, warmth, cold and pain.
Pressure
Vibration
Vibration
Burning hot
Cold, warmth and pain

42. The Tactile Senses Touch Pressure Temperature
Skin receptors that make us aware of how & where we’re being touched.
Pressure
Receptors beneath the skin that make us aware of deeper touch.
Temperature
Receptors are found just beneath the skin to give the sensation of hot, cold, and warm.

43. Brain areas involved in touch
somatosensory cortex
located in the parietal lobe

44. Ashley Blocker (right) feels neither pain
Pain tells the body that something has gone wrong. Usually pain results from damage to the skin and other tissues. A rare disease exists in which the afflicted person feels no pain.
OBJECTIVE 18| State the purpose of pain, and describe the biopsychosocial perspective on pain.
AP Photo/ Stephen Morton
Ashley Blocker (right) feels neither pain
nor extreme hot or cold.

45. Biopsychosocial Influences on Pain

46. Gate-Control Theory
Melzak and Wall (1965, 1983) proposed that our spinal cord contains neurological “gates” that either block pain or allow it to be sensed.
One way to treat chronic pain is to stimulate it through massage by electrical stimulation or acupuncture. Rubbing causes competitive stimulation to pain thus reduces its effect.
Gary Comer/ PhototakeUSA.com

48. Pain Control
Pain can be controlled by a number of therapies including, drugs, surgery, acupuncture, exercise, hypnosis, and even thought distraction.
Burn victims can be distracted by allowing them to engage in illusory virtual reality. Their brain scans show differences in pain perceptions.
Todd Richards and Aric Vills, U.W.
©Hunter Hoffman,

49. Touch Receptors located in our skin. Gate Control Theory of Pain
Three sensations?
Touch, pressure, temperature
Gate Control Theory of Pain

50. Body Position and Movement
The sense of our body parts’ position and movement is called kinesthesis. The vestibular sense monitors the head (and body’s) position.
OBJECTIVE 21| Distinguish between kinesthesis and vestibular sense.
Bob Daemmrich/ The Image Works
Whirling Dervishes
Wire Walk

51. Grace and Balance The Kinesthetic Sense
Keeps us informed about movement of body parts & their position in relation to each other.
Muscle Movement, Posture, & Joints
Information comes from stretch receptors, the tendons, & the internal organs.

52. Kinesthetic Sense Tells us where our body parts are.
Receptors located in our muscles and joints.
Without the kinesthetic sense you could touch the button to make copies of your buttocks.

53. Balance & Equilibrium Vestibular Sense
keeps us informed about balance & the position of our body in space.
Hair cells in the inner ear bend in relation to the position & movement of the head giving information that the brain uses to help us maintain our balance and to sense changes in our movement through space.

54. Vestibular Sense Tells us where our body is oriented in space.
Our sense of balance.
Located in our semicircular canals in our ears.

55. Adapted from APPsychology.com