The EarOuter Ear: Collects and sends sounds to theeardrum.Middle Ear: Chamber between eardrum andcochlea containing three tiny bones (hammer,anvil, stirrup) that concentrate the vibrationsof the eardrum on the cochlea’s oval window.Inner Ear: Innermost part of the ear,containing the cochlea, semicircular canals,and vestibular sacs.
CochleaCochlea: Coiled, bony, fluid-filled tube in theinner ear that transforms sound vibrations to auditory signals.
Localization of SoundsBecause we have two ears, sounds that reach one ear faster than the other ear cause us to localize the sound.
Localization of Sound: How we locate sound 1. Intensity differences 2. Time differencesTime differences as small as 1/100,000 of a secondcan cause us to localize sound. The head acts as a “shadow” or partial sound barrier.
• Show auditory transduction video clip (1)• http://www.youtube.com/watch?v=PeTriGTENoc
TouchThe sense of touch is a mix of four distinct skin senses—pressure, warmth, cold, and pain.Bruce Ayers/ Stone/ Getty Images
Skin SensesOnly 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
Pain Pain tells the body that something has gonewrong. Usually pain results from damage to the skin and other tissues. A rare disease exists in which the afflicted person feels no pain. AP Photo/ Stephen Morton Ashley Blocker (right) feels neither pain nor extreme hot or cold.
There is no one type of stimulus that triggers pain. However, there are different nociceptors—sensory receptors that detect hurtful temperatures, pressure or chemicals.
Biopsychosocial Influences: Our experience of pain is much more than neural messages sent to the brain.
Pain: Gate-Control TheoryMelzack and Wall (1965, 1983) proposed that our spinal cord contains neurological “gates” that either block pain or allow it to be sensed. Gary Comer/ PhototakeUSA.com
According to the gate-control theory, the spinal cord contains a neurological “gate” that blocks pain signals or allows them to pass. The “gate” is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers.Based on the gate-control theory, one way to treat chronic pain is to stimulate (massage, electric stimulation, acupuncture) gate-closing activity in the large neural fibers (because they close the gate when activated).
Brain to spinal cord messages can also close the gate. The release of endorphins can greatly diminish our experience of pain. (Ex: sports injuries or vehicle accident injuries go unnoticed till some time later).The brain can help buffer pain and it can also create pain. People who experience phantom limb sensations is a good example. About 7 – 10 amputees may feel pain or movement in a nonexistent limb.Similar phenomenon include phantom sounds (in people with hearing loss) and phantom sights—nonthreatening hallucinations (in people who have had a loss in their normal vision.There are also phantom tastes and phantom smells.The point to remember here is that we feel, see, hear, taste, and smell with our brain, which can sense things even without functioning senses.
• Show clip on The role the brain plays in pain (2)• http://www.youtube.com/watch?v=ldyI7mJG2EA
Taste SensationsCommonly, taste sensations consist of 4 tastes. What are they?
Taste Traditionally, taste sensations consisted of sweet,salty, sour, and bitter tastes. Recently, receptors fora fifth taste have been discovered called “Umami”. Sweet Sour Salty Bitter Umami (Fresh Chicken)
• Taste receptors (taste buds) regenerate every 1 or 2 weeks, but age, smoking, and alcohol will lower taste bud number and sensitivity.• There are taste buds on the top and sides of the tongue and in the back and on the roof of the mouth. These taste buds contain taste receptor cells.• The taste receptor cells send information to an area of the temporal lobe.
Sensory Interaction When one sense affects another sense, sensoryinteraction takes place. So, the taste of strawberry interacts with its smell and its texture on the tongue to produce flavor.
SmellLike taste, smell is a chemical sense. Odorants enter the nasal cavity to stimulate 5 millionreceptors to sense smell. Unlike taste, there are many different forms of smell.
Smell and Memories The brain region forsmell (in red) is closely connected with thebrain regions involved with memory (limbic system). That is why strong memories aremade through the sense of smell.
• Show video clip on olfactory sensation psychology project (4)• http://www.youtube.com/watch?v=GP1VRpODyz4
Body Position and Movement The sense of our body parts’ position and movement is calledkinesthesis. The vestibular sense monitors the head (and body’s)position. Kinesthesis is the system for sensing the position and movement of individual body parts. Sensors in the muscles, tendons, and joints are continually providing our brain with information. A companion vestibular sense monitors the head’s (and thus the body’s) position and movement. The biological gyroscopes for this sense of equilibrium are in the inner ear. http://www.heyokamagazine.com Bob Daemmrich/ The Image Works Whirling Dervishes Wire Walk
• Show clips on body position and balance (5)• http://www.youtube.com/watch?v=BbKU0AbbARg