CSD-2260 Lecture 22: Chapter 9
1 Dec 2016
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Document Summary
The functions and structures of hearing: audition. Ear changes acoustic energy into electrochemical energy. Schematic of frontal section revealing outer, middle, and inner ear. Structures of the outer ear: pinna (auricle) structures. Collector of sound that is processed in the middle ear and cochlea: external auditory meatus (eam) Two-thirds of ear canal housed in bone temporal. One-third of ear canal composed of cartilaginous. Tympanic membrane: also known as the eardrum, separates the middle ear from the outer ear, responsible for initiating mechanical impedance-matching process of middle ear. Middle ear: contains the three smallest bones of the body, bones of middle ear called ossicles, ossicular chain: collective name for ossicles. Nine mm long and weighs only 25 mg. Provides point of attachment with tympanic membrane. Bulk of bone is the head or caput. Weighs 30 mg and is around 7 mm long. Incus and malleus articulate by means of a saddle joint: stapes (stirrup)
