The fine structure of teleost epidermis: I. Introduction and filament-containing cells

Abstract

A study of teleost (bony fish) epidermis by light and electron microscopy has demonstrated that this epidermis consists predominantly of filament-containing cells. In comparing teleost epidermis with that of mammals, the absence of a cell sequence comparable to basal, spinous, granular, and horny cells is immediately apparent. In filament-containing cells most organelles cluster around the centrally placed nucleus and 70 Å diameter filaments course through the peripheral cytoplasm. Shorter and less dense filamentous wisps and ribosomes are seen between the filaments and central organelle complex. These filamentous wisps are thought to represent precursors of the more peripheral filaments. Filament-containing cells in the basal and mid-layers of the epidermis are structurally similar. Differentiation of these cells is apparent only in the surface layer where microvilli develop which are covered by a fuzz layer; a terminal web is formed, an overall increase in protoplasmic density occurs, and some organelles undergo structural changes.