PNB 2250 Lecture Notes - Lecture 37: Interaural Time Difference, Sound Localization, Inner Ear
7 Dec 2016
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Document Summary
A type of energy: varied sensitivity (owls and dogs, snakes- very sensitive to vibrations. Hearing: found in fish, amphibians, land vertebrates and whales, external ear- focuses sound energy, middle ear- amplifies sound energy, inner ear- detects sound acts as a spectral analyzer, gives information on frequency (hz) and intensity (loudness) Evolution: ability to hear arose several times independently in several different lineages, structure of the external, middle and inner ear is different, but the physiology is the same. Receptacles to collect sound energy and focus it onto a membrane (tympanic) which vibrates. Vibration of tympanic membrane is detected by specialized hair cells. Activation of hair cells is how sound is detected. There also two ears: places on the side of the head. Sound reaches ear at slightly different times. Ild- interaural level difference: different acoustic signals can be used to determine direction (vector) distance, and azimuth (angle) Ear placement: on the side of the head.
