TAILIEUCHUNG - Chapter 030. Disorders of Smell, Taste, and Hearing (Part 7)

Ear anatomy. A. Drawing of modified coronal section through external ear and temporal bone, with structures of the middle and inner ear demonstrated. B. High-resolution view of inner ear. Stereocilia of the hair cells of the organ of Corti, which rests on the basilar membrane, are in contact with the tectorial membrane and are deformed by the traveling wave. A point of maximal displacement of the basilar membrane is determined by the frequency of the stimulating tone. High-frequency tones cause maximal displacement of the basilar membrane near the base of the cochlea. As the frequency of the stimulating tone decreases,. | Chapter 030. Disorders of Smell Taste and Hearing Part 7 Ear anatomy. A. Drawing of modified coronal section through external ear and temporal bone with structures of the middle and inner ear demonstrated. B. High-resolution view of inner ear. Stereocilia of the hair cells of the organ of Corti which rests on the basilar membrane are in contact with the tectorial membrane and are deformed by the traveling wave. A point of maximal displacement of the basilar membrane is determined by the frequency of the stimulating tone. High-frequency tones cause maximal displacement of the basilar membrane near the base of the cochlea. As the frequency of the stimulating tone decreases the point of maximal displacement moves toward the apex of the cochlea. The inner and outer hair cells of the organ of Corti have different innervation patterns but both are mechanoreceptors. The afferent innervation relates principally to the inner hair cells and the efferent innervation relates principally to outer hair cells. The motility of the outer hair cells alters the micromechanics of the inner hair cells creating a cochlear amplifier which explains the exquisite sensitivity and frequency selectivity of the cochlea. Beginning in the cochlea the frequency specificity is maintained at each point of the central auditory pathway dorsal and ventral cochlear nuclei trapezoid body superior olivary complex lateral lemniscus inferior colliculus medial geniculate body and auditory cortex. At low frequencies individual auditory nerve fibers can respond more or less synchronously with the stimulating tone. At higher frequencies phase-locking occurs so that neurons alternate in response to particular phases of the cycle of the sound wave. Intensity is encoded by the amount of neural activity in individual neurons the number of neurons that are active and the specific neurons that are activated. Genetic Causes of Hearing Loss More than half of childhood hearing impairment is thought to be hereditary .

• Y học thường thức
• Disorders of Smell
• Taste
• Hearing
• bệnh học và điều trị
• bài giảng bệnh học
• tài liệu học ngành y
• Harrisons Internal Medicine
• Taste disorders
• Smell and taste disorders
• Non neurodegenerative disorders
• Neurodegenerative chemosensory disorders
• Chemosensory disorders
• Medicolegal aspects
• Physiology of olfaction
• Anatomy and physiology of gustation
• Measurement of gustation
• Measurement of olfaction
• medical books
• pharmacology
• epidemiologic
• Obstetrics
• anatomy
• Preventing Morbidity
• Multidisciplinary Care