Elements of animal physiology, chiefly human . he sidesof the velum or soft palate. 357. Sound.—The external cause of sound is meremechanical movement. Sound is almost invariably pro-duced by air in a state of sonorous vibration, that is, airoscillating backwards and foriuards with great the wave movement be either too quick or too slow, itwill not produce sound. 358. The Sensation of Hearing is excited in the brainby means of a molecular movement, set up in the nervefibrils of the internal ear or labrynth, by the rapid vibra-tion of some external elastic body, and transmitted toth
Elements of animal physiology, chiefly human . he sidesof the velum or soft palate. 357. Sound.—The external cause of sound is meremechanical movement. Sound is almost invariably pro-duced by air in a state of sonorous vibration, that is, airoscillating backwards and foriuards with great the wave movement be either too quick or too slow, itwill not produce sound. 358. The Sensation of Hearing is excited in the brainby means of a molecular movement, set up in the nervefibrils of the internal ear or labrynth, by the rapid vibra-tion of some external elastic body, and transmitted tothe brain by the auditory nerve. The essential parts of 160 ANIMAL PHYSIOLOGY. the organs of hearing are the membranous lahyrinth, andthe scala media of the cochlea. 359. The Organs of Hearing (the ears)—each consist ofthree parts, viz.:— (1.) The external ear, comprising the pinna or auricle,the gristly appendage attached to the side of the head, Vestibule. 3 Semi-circular Incus or Anvil External Jleatus Ciiuals. Bone. AuUitoriua. Helix,. fenestra Stapes, its Inside of Malleus or tobule. Jiotunda. base over Menibrana Hammer Bone. Fenestra Fig. 75. Diagram of Ear. (which both serves as a natural ornament and to collect thevibrations of the air,) and the auditory canal (meatus) orpassage by which the vibrating air is conducted to themembrane of the tympanum. The meatus is lined bymucous membrane, studded with the ceruminous or waxglands. (2.) The tympanum, or middle ear, (which consists ofan irregular cavity in the petrous part of the temporalhone), bounded on its outer side by the memhranatympani, and on its inner side by the outer wall of thehony lahyrinth. It is traversed by a chain of movablebones, consisting of the malleus or hammer bone, theincus or anvil bone, the stapes or stirrup bone, by which THE SEMICIRCULAR CANALS. IGl the vibrations are conveyed from the external air,through the middle ear, to the membrane in the fenestirtovalis in the side of t
Size: 1760px × 1420px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookce, bookdecade1870, booksubjectanatomy, booksubjectphysiology
