Ultrastructure of the cilia of thymic cysts in “nude” mice


  • Andre C. Cordier

    1. Department of Histology, University of Louvain, Avenue E. Mounier, 52, 1200 Bruxelles, Belgium
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    • Aspirant of the “Fonds National de la Recherche Scientifique.”

  • This work was supported by Grant 10,013 from the “Fonds de la Recherche Fondamentale Collective,” Bruxelles, Belgium.

  • Directeur: Professeur S. HAUMONT, Department of Histology, University of Louvain, Tour Vésale 5229 Avenue E. Mounier, 52, 1200 Bruxelles, Belgium.


The ciliary ultrastructure is studied in the ciliated cells of the thymic cysts of the “nude” mouse. The cilium is made up of two segments: the intracellular basal body and the extracellular cilium shaft.

The basal body extends in a rootlet and demonstrates three annexes: basal foot, anchoring system and tonofibrillar web. The rootlet, composed of one central and nine peripheral chambers, is closely and constantly associated with smooth endoplasmic reticulum. The classical periodicity of the basal foot can be explained by its internal structure. The anchoring system binds the upper part of the basal body to the cell membrane. The cilium shaft is divided into four segments: implantation base, proximal segment, intermediate segment and tip. The details of particular structures in the implantation base and in the proximal segment are given on transverse and longitudinal sections. In the intermediate part, a peculiar desmosome-like structure, binds some doublets with the ciliary membrane. At the tip level, A tubules end up in an opaque plate and membranes are covered with several intricated cristae.