Electron microscopic observations on single cilia in the intrahepatic biliary ducts in some birds.

Abstract

Summary. The intrahepatic biliary passage in five species of birds was investigated with the transmission electron microscope. The avian liver was characterized by a frequent occurrence of intralobular bile ductules and canaliculo-ductular junctions in the parenchyme. It was further characterized by solitary bile ductular epithelial cells intercalated among hapatocytes surrounding bile canaliculi.The present study first revealed that avian bile ductular epithelial cells possess a long single cilium. Its basal body (distal centriole) was connected to a basal foot and slender rootlet and accompanied by a proximal centriole. The hepatocytes facing the bile passage possessed no cilium, although they frequently had a diplosome in their apical cytoplasm. The single cilia of the bile ductular epithelium gradually tapered toward the tip. The original fiber pattern in the most proximal part was peripheral 9 doublets +0. In the ciliary shaft, the doublets altered into ringlets which were diminished in number gradually toward the distal parts of the shaft, so that in the tip only one singlet remained. Since these fiber patterns in the single cilia markedly deviated from the 9+2 fiber pattern of the ordinary motile cilia, they may not be motile, but properly regarded as sensory or chemoreceptors.Epithelial cells provided with single cilia have been demonstrated by many authors with transmission (TEM) and scanning electron microscopes (SEM) in normal and artificially proliferated intrahepatic biliary ducts in the rat and human (STEINER et al., 1962; STEINER and CARRUTHERS, 1963;GRISHAM, 1963;GRISHAM and PORTA, 1963;STERNLIEB, 1965). In their SEM observations, MOTTA and FUMAGALLI (1974), BROOKS et al. (1975) and GRISHAM et al. (1975) reported the actual length, number and orientation of the single cilia originating from the ductular epithelium in the rat liver. Recently, TANUMA and OHATA (1978a) have observed with TEM the single cilia in the intrahepatic biliary ducts of bats; they demonstrated the arrangement of ciliary microtubules and the pattern of the basal structures.In the course of our TEM study on normal livers in several species of birds, we occasionally found single cilia in the lumen of biliary ducts. We carried out a detailed investigation on them, with the following findings.285

Electron microscopy of fat-storing cells in liver diseases with special reference to cilia and cytoplasmic cholesterol crystals.

“…The present electron microscopic study revealed the absence of the central microtubules, arms and spokes in the cilia of fat-storing cells. Therefore, the cilia of these cells are probably immotile, and likely play a role as a sensory or chemical receptor as such cilia are assumed to do in other types of cells (CURRIE and WHEATLEY,1966;OHATA et al, 1982b). Other authors have made the same assumption about the cilia of fat-storing cells (TANUMA et al, 1981;OHATA et al, 1984), although they could not demonstrate the axonemal ultrastructure.…”

The ultrastructure of liver cells of some herbivorous animals

“…There are few reports dealing with the ultrastructure of liver cells in herbivorous animals [1,2,9,[11][12][13].…”

“…The bile capillaries are formed by membranes of contacting hepatocytes, but in the pigeon the bile capill~-~ is sometimes constructed by a membrane of one hepatocyte, as other authorities have also noted [12].…”

Scanning Electron Microscopic Study of Vascular and Biliary Casts in Chicken and Duck Liver

“…The canaliculo-ductular junction is between the terminal of the bile capillary and ductile. It is lined with both hepatocytes and epithelial cells [12]. Because chicken and duck have gallbladders, their biliary plexus might have an important function to exchange materials with a small branch of the portal vein through the thin venous wall.…”