. Kirkes' handbook of physiology . for con-ducting sound. Since all matter is capable of propagating sonorous vibra-tions, the simplest conditions must be sufficient for mere hearing; since allsubstances surrounding the auditory apparatus would stimulate it. The com-plex development of the organ of hearing, therefore, must have for its object THE PHYSIOLOGY ! HEARING 621 the more effective propagation of the sonorous vibrations and their intensi-fication by resonance; and, in fact, the whole of the acoustic apparatus maybe shown to have reference to these principles. The external ear and the a
. Kirkes' handbook of physiology . for con-ducting sound. Since all matter is capable of propagating sonorous vibra-tions, the simplest conditions must be sufficient for mere hearing; since allsubstances surrounding the auditory apparatus would stimulate it. The com-plex development of the organ of hearing, therefore, must have for its object THE PHYSIOLOGY ! HEARING 621 the more effective propagation of the sonorous vibrations and their intensi-fication by resonance; and, in fact, the whole of the acoustic apparatus maybe shown to have reference to these principles. The external ear and the auditory passages influence the propagation ofsound to the tympanum by collecting from the atmosphere the sonorous undu-lations that strike against the external ear and by transmitting them by theair in the passage to the membrana tympani. In animals living in the atmosphere, the sonorous vibrations are con-veyed to the auditory epithelium through three different media in series; linbtts mcmbrana tectoria outer hair-cellsU. nerve fibres inner rod vas basilar tpiralc membrane outer cells of Deitenrod Fig. 438.—Semidiagrammatic Representation of the Organ of Corti and Adjacent Structures.(Merkel-Henle.) a. Cells of Hensen; b, cells of Claudius; c, internal spiral sulcus; x, Nuels nerve fibers (dendrites of cells of the spinal ganglion) are seen passing to Cortis organ throughopenings (foramina nervosa) in the bony spiral lamina. The black dots represent longitudinally-running branches, one bundle lying to the inner side of the inner pillar, a second just to the outerside of the inner pillar within Cortis tunnel, the third beneath the outer hair cells. namely, the air of the external ear and meatus, which sets in vibration thetympanic membrane, the solid chain of auditory ossicles, and the fluid of thelabyrinth. Sonorous vibrations are imparted too imperfectly from air tothe solid structures of the body as a whole for the propagation of sound tothe internal ear to be ad
Size: 2347px × 1065px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectphysiology, bookyear1
