Nucleoli in human pseudostratified columnar epithelium cells. (Microscopic classification of nucleoli).

The human pseudostratified epithelium was investigated to provide more information on the incidence of main nucleolar types in its epithelial cells. The compact nucleoli or nucleoli with nucleolonemas investigated by light microscopy were usually present in epithelial cells with highly basophilic cytoplasm. The absence of these nucleoli and the presence of ring-shaped nucleoli and/or micronucleoli (reflecting the decrease or inhibition of the RNA synthesis) were observed in epithelial cells which were characterized by the diminished or disappeared basophilic properties of the cytoplasm. These observations indicating the gradual inhibition of the nucleolar (ribosomal) RNA suggest that similar maturation processes may occur in investigated human pseudostratified columnar epithelium which are known for cell lines of the mesenchymal origin.