title: Ultrastructural study on topographical variations of the ependyma in Bradypus tridactylus.
abstract: An electron-microscopic study of ependymal cells in 24 different areas of the encephalic ventricular system of Bradypus tridactylus was made, with a view to making a comparative analysis, of a topographical kind, of various cell components: cilia, microvilli, plasma membrane, cytoplasmic protrusions, types of cellular junctions, ribosomes, Golgi apparatus, endoplasmic reticulum, microfilaments, microtubules, mitochondria, granules and dense bodies. There were differences in the distribution of all these cytologic elements, according to the topography, being a complement to a similar work done by the same authors with light-microscopy. By means of a morphofunctional analysis they draw the conclusion that even if one can admit the passage of substances by an intracellular route, on the other hand few facts support the idea the intracellular absorption or secretion could be considered as important phenomena in a great number of the ependymal areas studied.
mesh_terms: D000818:Animals; D002923:Cilia / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D004721:Endoplasmic Reticulum / Q000648:ultrastructure; D004805:Ependyma / Q000648:ultrastructure*; D006056:Golgi Apparatus / Q000648:ultrastructure; D008870:Microtubules / Q000648:ultrastructure; D008928:Mitochondria / Q000648:ultrastructure; D012270:Ribosomes / Q000648:ultrastructure; D012896:Sloths / Q000033:anatomy & histology*; D004490:Xenarthra / Q000033:anatomy & histology*