耳蜗的扫描电镜观察

A PRELIMILARY SEM STUDY ON COCHLEAE

为研究柯替氏器的超微结构,用豚鼠、猫及4个月胎儿的耳蜗,在扫描电镜下观察。柯替氏器呈螺旋梯状,围绕在蜗轴周围。蜗尖部的柯替氏器较宽,蜗底部的较窄,其上方的前庭膜由单层扁平上皮组成,上皮表面有微绒毛。紧贴表面的盖膜由原纤维组成。大多数原纤维平行排列,表面与边缘的原纤维多交织成网。柯替氏器中有3排外毛细胞与1排内毛细胞,二者之间有柱细胞头板,外毛细胞上的听毛排列成W形,内毛细胞上的听毛排列成弧形。此外,所有细胞表面均有微绒毛。在轻度噪音刺激后,听毛减少并紊乱,微绒毛也减少或消失。4月胎儿的柯替氏器有3~4排外毛细胞,其表面为绒球状听毛,后来发育为W形排列。内毛细胞为1排,表面为束状的原始听毛,后变为弧形排列。本文还观察到断裂的柯替氏器中,暴露出外毛细胞的柱状胞体及底部的杯状支持结构。外毛细胞由外指细胞所肩托。外指细胞的指突与外毛细胞均倾斜排列,交错成一定角度。当暴露出外柱细胞时,其胞体上细下粗,表面有传入神经纤维。当外毛细胞、外柱细胞等掀向上方后,可见隧道中纵行的神经纤维束及其分支,即螺旋隧道束与放线隧道纤维,它们系橄榄耳蜗束的传出纤维。

Cochleae of guinea pig,cat,and human fetus were studied under SEM.After tbe treatment with osmic and tannic acids,they were dehydrated by a critical point drier,then coated with carbon and gold,and observed under a JSM-35 scanning electon microscope.The organ of Corti looks like a spiral staircase winding around the modiolus.It is wider at apex and narrower at base.The vestibular membrane is composed of squamous epithelia covered with microvilli.The tectorial membrane is mainly composed of parallel fibrils,but at its surface and marginal region,the fibillae interwoven.There are three rows of outer hair cells(OHC)and one row of inner hair cell(IHC)in the organ of Corti,and the head plate of pillar cells is set in between both kinds of cells.The stereocilia of OHC are arranged in W-form,whereas those of IHC are in a curved arrangement.All the cells observed have microvilli,however,in some of the animal specimens,the stereocilia are irregularly arranged,damaged or entirely disappeared owing to noise exposure.In the four-month fetal cochlea,the cuticular plates of OHC looks just like velvet balls,which afterwards become W-shaped stereocilia,while on the surface of IHC,primitive hair bundles develop into a curved arrangement.Certain broken organ of Corti shows cylindrical body of OHC and its cup-like supporting structure.Phalangeal processes of Deiter ceils and OHC are obliquely arranged forming an angle.The pillar cell body is thin above and thick below,and twined with very thin nerve network.The tunnel cavity can be exposed by removing the roof structures,then longitudinal nerve fibers going along the tunnel bottom may be clearly seen.These fibers belong to the spirotunnel bundle——an efferent branch of olivo-cochlear bundle.