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.
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1 March 1970
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March 01 1970
FORMATION OF HORNY CELLS : The Fate of Cell Organelles and Differentiation Products in Ruminal Epithelium
Robert M. Lavker,
Robert M. Lavker
From the Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts 02118
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A. Gedeon Matoltsy
A. Gedeon Matoltsy
From the Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts 02118
Search for other works by this author on:
Robert M. Lavker
From the Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts 02118
A. Gedeon Matoltsy
From the Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts 02118
Received:
August 14 1969
Revision Received:
October 07 1969
Online ISSN: 1540-8140
Print ISSN: 0021-9525
Copyright © 1970 by The Rockefeller University Press
1970
J Cell Biol (1970) 44 (3): 501–512.
Article history
Received:
August 14 1969
Revision Received:
October 07 1969
Citation
Robert M. Lavker, A. Gedeon Matoltsy; FORMATION OF HORNY CELLS : The Fate of Cell Organelles and Differentiation Products in Ruminal Epithelium . J Cell Biol 1 March 1970; 44 (3): 501–512. doi: https://doi.org/10.1083/jcb.44.3.501
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