Indexed on: 01 Sep '68Published on: 01 Sep '68Published in: Cell and Tissue Research
In the tracheal epithelium of adult rats “Brush Border Cells” are found arranged in pairs. Their special structures are narrowly placed and very regular microvilli, the axial filaments of which continue between a number of apical vesicles inside of the cell, without ending in a terminal web. The Golgi apparatus is situated supranuclear; the mitochondria are longitudinally oriented. Ribosomes are free or attached to the membranes of the endoplasmic reticulum. Furthermore there are single and aggregated granules of glycogen and lipid droplets.Along their lateral surface the brush border cells contact initial nerve fibres which contain numerous vesicles, mitochondria, microtubuli and endoplasmatic reticulum.In 14 day-old rats there are found initial nerve fibres in the undifferenciated epithelium. They contain numerous mitochondria with longitudinally oriented cristae. The dendritic branches partly envelope cells that are arranged in pairs like the brush border cells, and also show their typical cytoplasmatic structure. The brush border is missing, since these cells do not reach the free surface of the mucosa. Besides small mitochondria, filaments and numerous ribosomes they contain small accumulations of vesicles (synaptic vesicles) beneath the plasma membrane, on places which lie opposite of a thickened dendritic plasmalemma (postsynaptic membrane).The morphological characteristics of the brush border cells allow to assume that they are chemoreceptors. They make contact with dendrites and form afferent synapses respectively epithelio-neural junctions.Ciliated, goblet and replacement cells are innervated, too. They form contacts with telodendrites, that are efferent synapses or neuro-epithelial junctions and contain structures as they are widely spread in the autonomous nerve system.