. Human physiology. re dilated at their ends, and two of themunite at one extremity before entering the vestibule. The cochlea is aspiral tube, in shape like the shell of a snail. It consists oftwo and a half turns, wound round a central pillar called the modiolus (Lat. thenave of a wheel). A thin layer of bone projects from the modiolus, followingthe convolutions of the cochlea. The cochlea communicates with the tym-panum by an opening called the fenestra rotunda (round window), which isclosed by a membrane. The membranous labyrinth lies within the osseous labyrinth, and agreeswith it in gene
. Human physiology. re dilated at their ends, and two of themunite at one extremity before entering the vestibule. The cochlea is aspiral tube, in shape like the shell of a snail. It consists oftwo and a half turns, wound round a central pillar called the modiolus (Lat. thenave of a wheel). A thin layer of bone projects from the modiolus, followingthe convolutions of the cochlea. The cochlea communicates with the tym-panum by an opening called the fenestra rotunda (round window), which isclosed by a membrane. The membranous labyrinth lies within the osseous labyrinth, and agreeswith it in general form. The space between them is filled with a fluid 220 ELEMENTARY PHYSIOLOGY called the perilymph (Gr. peri, around ; and lymfha, clear water). Themembranous labyrinth is itself filled with a liquid called the endolymph (, within ; and lymfha). A number of minute crystals of carbonate oflime, called otoliths (Gr. ous, the ear ; and lithos, stone) are suspended inthe endolymph of the membranous Fig. 2ii.—Plan of the Eight Membranous Labyrinth. Branches of the auditory nerve supply fibres to the membra-nous labyrinth. The terminations of these fibres end in cellswhich are provided with delicate hair-like processes projectinginto the endolymph, some of them lying in close proximity to theotoliths. We may now trace the path along which the sound vibrationstravel. The waves collected by the pinna are reflected into theauditory canal, at the extremity of which they impinge against the
Size: 1632px × 1531px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherlondon, booksubject
