Cell and Tissue Research

, Volume 158, Issue 4, pp 481–496

Fine structure of the gastric epithelium of the ascidian Botryllus schlosseri. Mucous, endocrine and plicated cells

  • Paolo Burighel
  • Carla Milanesi

DOI: 10.1007/BF00220214

Cite this article as:
Burighel, P. & Milanesi, C. Cell Tissue Res. (1975) 158: 481. doi:10.1007/BF00220214


The following five cell types have been recognized and defined on the basis of their fine structure in the gastric epithelium of B. schlosseri: vacuolated and zymogenic cells (described in a previous paper); ciliated mucous, endocrine and plicated cells. The ciliated mucous cells are distributed at the apex and the bottom of the gastric folds and along the dorsal groove. The mucus droplets appear to form from the Golgi complex as secretory granules of variable density and texture, which are released from the cell after fusion of their membranes with the apical plasma membrane. Holocrine or apocrine secretion has not been observed. The endocrine cells are scattered and are characterized by electron dense granules, especially numerous in the basal region of the cell. Finally, the plicated cells, present in the pyloric caecum, show rod-like microvilli, a well developed Golgi complex and abundant, deep infoldings of the basal plasma membrane, which are associated with numerous mitochondria. The possible role of the gastric cell types is discussed taking into account information concerning morphologically similar cells in other animals, as well as previously reported data on the biochemistry and physiology of digestion and excretion in ascidians.

Key words

Gastric epitheliumAscidia (Botryllus schlosseri)Ciliated mucous, endocrine and plicated cellsStructure and functionElectron microscopy

Copyright information

© Springer-Verlag 1975

Authors and Affiliations

  • Paolo Burighel
    • 1
  • Carla Milanesi
    • 1
  1. 1.Institute of Animal BiologyUniversity of PaduaItaly
  2. 2.Istituto di Biologia AnimalePadovaItaly