FORMATION OF HORNY CELLS
FORMATION OF HORNY CELLS
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角质细胞的形成
作者：
R. M. Lavker;A. Matoltsy
上皮细胞从颗粒分化阶段向角质化阶段转变的数量更多，并且在电镜下比迄今为止研究的其他角化上皮更详细地揭示了瘤胃上皮的一系列转化事件。对这类细胞的研究表明，转化是由水解酶的释放开始的，溶酶体的出现证明了这一点。随着溶酶体数量的增加，细胞核、核糖体、线粒体、高尔基体和黏液颗粒逐渐降解。此外，当大量裂解的细胞成分通过并以无定形团块的形式积聚在细胞间隙时，质膜的渗透性发生显著变化。细丝、角透明素颗粒和ER （ER蛋白）的含量未被裂解，表明释放的酶的作用是特异性的。在转化过程中，纤维向细胞周围移位，角化素颗粒分散并与细胞中心的er蛋白混合。随后，角透明蛋白- er蛋白复合物渗透到纤维网络中，从而形成纤维-无定形细胞内容物。通过质膜的液体损失导致细胞体积减小和剩余细胞内容物的巩固。细胞间形成的深层交错最终将上皮的外层相互联结，形成具有凝聚力和保护性的角质层。
Epithelial cells changing from the granular stage of differentiation to the horny stage are more numerous, and reveal sequential events of transformation in finer detail in the rumen epithelium than in other keratinizing epithelia thus far studied in the electron microscope. Studies of such cells indicate that transformation is initiated by the release of hydrolytic enzymes, as evidenced by the appearance of lysosomes. As lysosomes increase in number, the nucleus, ribosomes, mitochondria, Golgi apparatus, and mucous granules are gradually degraded. Furthermore, marked changes occur in permeability of the plasma membrane as voluminous amounts of the lysed cell components pass through and accumulate in the intercellular space in the form of an amorphous mass. Filaments, keratohyalin granules, and the content of the ER (ER-protein) are not lysed, revealing the action of released enzymes to be specific. During transformation, filaments become displaced toward the cell periphery and keratohyalin granules disperse and mix with the ER-protein in the cell center. Subsequently, the keratohyalin-ER-protein complex infiltrates the filament network whereby a fibrous-amorphous cell content is formed. Loss of fluids through the plasma membrane leads to reduction of cell volume and consolidation of the remaining cell content. The deep interdigitations formed between the cells ultimately interlock the outer part of the epithelium into a cohesive and protective stratum corneum.