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THE AUDITORY SYSTEM SENSE OF HEARING THE AUDITORY SYSTEM Mechanoreception: detection of vibration, perceived as hearing Stimulus: sound waves Sense organ: ears Function: hearing Auditory transduction: transforms sound waves into electrochemical impulses that the brain can interpret SOUND WAVE PROPERTIES Sound has 3 characteristics: 1. Wavelength: frequency (determines pitch) • longer = lower frequency = lower pitch • shorter = higher frequency = higher pitch • measured in hertz = Hz 2. Wave amplitude: intensity (determines loudness) • shorter = less intensity = quieter • taller= more intensity = louder • measured in decibels = dB • roughly every 10 dB doubles loudness 3. Purity: quality (determines timbre/tone saturation) • uniqueness of sound PARTS OF THE EAR Outer ear – air conduction Pinna Auditory canal Middle ear – bone conduction Eardrum (tympanic membrane) Ossicles Hammer (malleus), anvil (incus), stirrup (stapes) Inner ear – fluid conduction Oval window Cochlea Basilar membrane and hair cells Semicircular canals Vestibular sacs Auditory nerve PITCH PERCEPTION Place Theory States that each frequency produces vibrations at a particular spot on the basilar membrane. Location Explains high pitched sounds Frequency Theory States that the perception of a sound's frequency depends on how often the auditory nerve fires. Neural impulses Explains low pitched sounds VOLLEY PRINCIPLE Modification of frequency theory stating that a cluster of nerve cells can fire neural impulses in rapid succession, producing a volley of impulses. Fixes limitations of frequency theory AUDITORY LOCALIZATION We have two ears Sounds may reach one ear faster than the other ear Or sounds may be louder in one ear than another This let’s us locate the sound Our head acts as a “shadow” Sound shadow Can not localize if directly in front, back or above HEARING LOSS Conductive Hearing Loss Sensorineural Hearing Loss hearing loss occurs when there is Hearing loss occurs when sound is damage to the inner ear (cochlea), or not conducted efficiently through to the nerve pathways from the inner the outer ear canal to the eardrum ear to the brain. and the tiny bones (ossicles) of Most of the time, cannot be the middle ear. medically or surgically corrected. Usually involves a reduction in most common type of permanent sound level or the ability to hear hearing loss. faint sounds. reduces the ability to hear faint Can often be corrected medically or sounds. surgically Caused by damage to the cochlea or to the auditory nerve Caused by damage to the parts of the ear that connect to the cochleaHearing Loss Mixed HEARING LOSS THE TACTILE SYSTEM SENSE OF TOUCH THE TACTILE SYSTEM Mechanoreception: detection of pressure, perceived as touch Thermoreception: detection of temperature; perceived as warm and cold Nociceptors: detection of noxious stimuli; perceived as pain Stimulus: mechanical, thermal, and chemical energy Sense organ: skin Function: touching Tactile transduction: transforms mechanical, thermal, and chemical energy on the skin into electrochemical impulses that the brain can interpret THE SENSORY SYSTEM Three kinds of receptors: touch temperature warm cold pain Four distinct skin senses: pressure warmth cold pain Extreme heat & extreme cold are THE SAME! PAIN Pain tells the body that something has gone wrong. Congenital Insensitivity to Pain (CIP): A rare disease in which the afflicted person feels no pain. no sense of smell unable to sweat sodium channel mutation PAIN PATHWAYS Two pain pathways: fast A-delta fibers • less than 1 second • myelinated slow C fibers • a couple of seconds • unmyelinated PAIN PERCEPTION Gate Control Theory: creates neural blockage Studied by Ronald Melzack & Patricia Wall (1965) ENDORPHINS Neurotransmitters natural opiate morphine-like painkillers THE GUSTATORY SYSTEM SENSE OF TASTE THE GUSTATORY SYSTEM Chemoreception: detection of chemical stimuli, perceived as taste Stimulus: soluble chemicals Sense organ: tongue Function: tasting Gustatory transduction: transforms soluble chemicals in food into electrochemical impulses that the brain can interpret THE OLFACTORY SYSTEM SENSE OF SMELL THE OLFACTORY SYSTEM Chemoreception: detection of chemical stimuli, perceived as smell Stimulus: volatile chemicals Sense organ: nose Function: smelling Olfactory transduction: transforms volatile chemicals in the air into electrochemical impulses that the brain can interpret THE KINESTHETIC SYSTEM SENSE OF POSITION & MOVEMENT THE KINESTHETIC SYSTEM Mechanoreception: detection of vibration, perceived as hearing Stimulus: sound waves Sense organ: ears Function: hearing Auditory transduction: transforms sound waves into electrochemical impulses that the brain can interpret THE VESTIBULAR SYSTEM SENSE OF BALABNCE & MOVEMENT THE VESTIBULAR SYSTEM Mechanoreception: detection of vibration, perceived as hearing Stimulus: sound waves Sense organ: ears Function: hearing Auditory transduction: transforms sound waves into electrochemical impulses that the brain can interpret THE th 6 SENSE EXTRASENSORY PERCEPTION (ESP) PARAPSYCHOLOGY The study of paranormal phenomena. Over 75 years of research No evidence of paranormal phenomena exists EXTRASENSORY PERCEPTION Perception without sensory input. Energy source? Sensory receptors? Paranormal phenomena include: Astrological predictions, psychic healing, communication with the dead, out-of-body experiences, telepathy, clairvoyance, and precognition. TYPES OF ESP Telepathy: Mind-to-mind communication. One person sending thoughts and the other receiving them. Clairvoyance: Perception of remote events. Precognition: Perceiving future events.