An electron microscopic study of filaments and microtubules in the chief cells of the epithelium of the rat intestine.

Within the short history of the application of electron microscopy to cytological and histological problems, most of the emphasis has fallen on the membraneous components of the cell. Mitochondria, the Golgi apparatus, granular and agranular endoplasmic reticulum, and the nuclear envelope have all been studied intensively. There have also been many studies on specializations of the cell membrane (Fawcett, 1962). Only recently have intracellular filaments been given some attention by electron microscopists, although they still have not gained acceptance as an ubiquitous organelle in epithelia. Most descriptions of cytoplasmic filaments have been made in conjunction with studies on terminal bars or desmosomes. [...