190 likes | 348 Views
Hearing . Audition is caused by vibrations Social relationships ASL= American sign language. Hearing: If a tree falls in the Forest…. How sound waves are produced? How they are sensed? How senses are interpreted?. Objectives= The Student will.
E N D
Hearing Audition is caused by vibrations Social relationships ASL= American sign language
Hearing: If a tree falls in the Forest… • How sound waves are produced? • How they are sensed? • How senses are interpreted?
Objectives= The Student will • Compare and contrast the psyical properties of sound • Describe The psychological aspect of hearing • Trace and summarize How we hear (4 STEPS)
Frequency and Amplitude • Two physical properties of sound waves • Frequency- number of vibrations or cycles the wave completes in a given amount of time. • Cycles per second (cps) or hertz (Hz). • Amplitude- Measure of physical strength of the S.W. • Units of sound pressure or energy. • For example: Turn down stereo=decreasing amplitude of S.W.
Sound Waves • Physics of S.W.
chapter 6 What we hear Loudness The dimension of auditory experience related to the intensity of a pressure wave Pitch The dimension of auditory experience related to the frequency of a pressure wave Timbre The dimension of auditory experience related to the complexity of a pressure wave
Psychological Qualities of sound: How we Distinguish one sound from another (OB2) • Three sensory qualities: Pitch, loudness, timbre. • How does the two physical characteristics of sound, (Frequency and amplitude), produce these 3 psychological sensations?
Sensations of a pitch • Sound waves frequency determines highness or lowness of sound= Pitch. • High frequency=high pitch • Low frequency=low pitch • Range of human auditory sensitivity 20 cps- 20,000 cps
Sensation of loudness • Loudness is determined by it’s physical strength or amplitude. • Like brightness is determined by intensity of light • Measured in decibels ( a unit named after Alexander graham bell) dB
Sensations of Timbre • Timbre-Complex quality of sound wave. • Allows you to recognize voice of friend • Sound is not a physical phenomenon; it is a psychological sensation
chapter 6 An ear on the world
Sensing Sounds: How we hear Sound Waves • Transduced into Neural Impulses for the Brain. Just like vision. • Happens in 4 steps. • 1st Airborne sound waves must reach the inner ear through auditory canal (outer) • Vibrating waves strike ear drum or Tympanic membrane. • Cochlea- Primary organ of hearing
Hearing Cont… • 2nd step The Cochlea focuses the vibrations on the basilar membrane • The airborne sound becomes Seaborne (the cochlea is filled with fluid) • Like a submarine sending a ping through the water • Causes a sympathetic vibration in the Basilar membrane. • B.M.- thin strip of tissue in Cochlea.
Hear me know? • 3rd step-B.M. converts the vibrations into neural messages. • Tiny hair cells on B.M. stimulate sensory nerve endings connected to hair cells • Excited Neurons transform into neural activity
4th step • Finally, the neural messages travel to the Auditory cortex in the brain. • Causes a bundle of nerves called auditory nerve. • Neurons from the two ears meet at the brain stem, then continue to A.C. for high processing. • Remember the auditory cortex lies in the Brain’s temporal lobes.
Receptor Cells- LIKE THE RETINA FOR HEAING • Cilia- the hair cells, have bristles • Organ Of Corti- The actual structure in the cochlea (KOCK-lee-uh) containing hair cells that serve as the receptor cells for hearing • Interior of cochlea- A snail shaped, fluid filled organ of Corti, where the receptors for hearing are located
chapter 6 Auditory localization Sounds from different directions are not identical as they arrive at left and right ears. Loudness Timing Phase The brain calculates a sound’s location by using these differences.
Deafness:2 types • Conduction deftness-The ways in which sound waves are converted to nerve energy have been interfered with or are interrupted. (vibrations effected) • Nerve deftness-problem with how the impulses from the oval window are sent to the brain. (usually people who are born deaf have this)
Summary • How we hear • Structure of sound • Anatomy of ear