ANATOMY, PHYSIOLOGY, AND DISORDERS OF THE AUDITORY SYSTEM - PART 1 pps

[...]... about the function of the cochlea than of any other sensory organ C H A P T E R 1 Anatomy of the Ear 1 ABSTRACT 10 1 The ear consists of the outer ear, the middle ear and the inner ear 2 The outer ear consists of the pinna and the ear canal 3 The skin of the ear canal is innervated by four cranial nerves: the trigeminal; the facial; the glossopharyngeal; and the vagus nerves 4 The middle ear consists of. .. ligaments (Figs 1. 3 and 1. 4) The manubrium of the malleus is embedded in the tympanic membrane with the tip of the manubrium located at the apex of the tympanic membrane (Fig 1. 5) The head of the malleus is suspended in the epitympanum The short process of the incus rests in the fossa incudo of the malleus, and it is held in place by the posterior incudal ligament The long process, also called the lenticular... how their function can change and cause different symptoms The book also covers less common disorders such as bilirubinemia and cortical lesions and it discusses vestibular Schwannoma and their diagnosis Because of the complexity of many disorders of the auditory system the clinician must have a thorough understanding of the basic functions of the entire auditory system and the interactions between the. .. attached to the manubrium of the malleus and the other, the stapedius muscle, is attached to the stapes (Figs 1. 3 and 1. 4) The tensor tympani muscle extends between the malleus and the wall of the middle-ear cavity near the entrance to the Eustachian tube When contracting, it pulls the manubrium of the malleus inward, displacing the tympanic membrane inwards and stretching the membrane The stapedius... Cavities The middle-ear cavities consist of the tympanum (the main cavity) that lies between the tympanic membrane and the wall of the inner ear (the promontorium), a smaller part (the epitympanum) that is located above the tympanum, and a system of mastoid air cells The head of the malleus is located in the epitympanum (Fig 1. 3) The middle-ear cavity and the Eustachian tube are covered with mucosa The. .. (Fig 1. 15) The endolymphatic sac is the space between two layers of the dura mater It is located close to the skull wall, near the porus acousticus (the opening of the internal auditory meatus) The pressure 16 Section I The Ear FIGURE 1. 14 Schematic drawing of the fluid system of the cochlea (reprinted from Marchbanks, 19 96, with permission from Springer) or rather the volume in the different compartments... have approximately the same number 11 µm = 1 micrometer = 1/ 1,000,000 of 1 m, or 1/ 1,000 of 1 mm A human hair is approximately 10 0 µm; a red blood cell is approximately 7 µm 12 Section I The Ear FIGURE 1. 8 (Continued) (B) Breschet's drawings of the cochlea, the spiral lamina, and the cochlear nerve The smaller sketches show differences between the mammalian cochlea and the avian organs of hearing (reprinted... that disorders of one part of the auditory system often affect the function of other parts of the auditory system This is especially apparent with regard to hyperactive disorders such as tinnitus and hyperacusis, but even noise induced hearing loss and presbycusis are not isolated cochlear phenomena, for the auditory nervous system is involved in these disorders Expression of neural plasticity and a... ear consists of the tympanic membrane that terminates the ear canal (Fig 1. 3) and the three small bones (ossicles), the malleus, the incus and the stapes (Fig 1. 3 and Fig 1. 4) Two small muscles, the tensor tympani muscle and the stapedius muscle, are also located in the middle ear The manubrium of malleus is imbedded in the tympanic membrane and the head of the malleus is connected to the incus that... hair cells while other efferent fibers terminate on the dendrites of the type I fibers that innervate the inner hair cells 2 INTRODUCTION The ear (Fig 1. 1) consists of three parts: the outer ear; the middle ear; and the inner ear The inner ear consists of two parts: the vestibular apparatus for balance; and the cochlea for hearing The outer ear and the middle ear conduct sound to the cochlea, which . anatomy, physiology, and disorders of the auditory system/ A.R. Moller, 2nd ed. p. cm. Includes bibliographical references and index. ISBN -1 3 : 97 8-0 -1 2-3 72 51 9-6 (casebound : alk. paper) ISBN -1 0 : 0 -1 2-3 72 51 9-4 . Frequency Discrimination of Complex Sounds 11 3 5.3. Preservation of the Temporal Code of Frequency 11 5 5.4. Preservation of the Place Code 11 7 5.5. Robustness of the Temporal Code 11 7 5.6. Robustness of the Place. recognized that disorders of one part of the auditory system often affect the function of other parts of the auditory system. This is especially apparent with regard to hyperactive disorders such