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

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.

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.

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.

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

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. http://www.pc.rhul.ac.uk

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

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.

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

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

Why do we have two ears?

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.

Smell and Taste

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

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

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

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?

Tongue

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

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

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.

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

The Tongue

Gustatory Pathway Figure 15.2

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.

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.

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

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, …

Cilia: Nose Hairs

Sense of Smell Figure 15.3

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.

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.

Gender related odors Can you smell the difference between?

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.

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

Let us not forget about Nurture

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Somesthetic Senses Soma  body Esthetic  feeling Touch Kinesthetic Vestibular

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

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

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.

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

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.

Biopsychosocial Influences on Pain

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

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, www.vrpain.com

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

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. http://www.heyokamagazine.com Bob Daemmrich/ The Image Works Whirling Dervishes Wire Walk

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.

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.

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.

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

Adapted from APPsychology.com