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Ultrastructural and histochemical studies on the epithelium revestment layer in the tube feet of the starfish Asterina stellifera
Author(s) -
de Souza Santos Helena,
da Silva Sasso Wilson
Publication year - 1970
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1051300303
Subject(s) - cuticle (hair) , ultrastructure , fibril , biology , organelle , biophysics , anatomy , matrix (chemical analysis) , arthropod cuticle , electron microscope , epithelium , ground substance , microbiology and biotechnology , insect , materials science , botany , composite material , connective tissue , physics , genetics , optics
The “cuticle,” which revests the starfish tube foot, has been studied by electron microscopy and the findings correlated with histochemical observations. The “cuticle” is composed by two distinct zones; an outer zone including numerous microvilli, which extend from the inner zone into and through a fibrillar substance distinctly organized in two layers. These microvilli protrude slightly beyond the outer surface, where their tips give rise tonumerous extremely delicate fibrils. The second inner zone, of quite variable thickness and condensation of material, presents a coarser fibrous matrix where organelles and inclusions can be found. The whole cuticular complex does not derive from the majority of the epithelial cells, but is probably an extension of a special kind of T‐shaped cells appearing at intervals, the “cuticle” forming a syncytial surface. Histochemical investigations indicate that the “cuticle” contains a combination of neutral and acid mucopolysaccharide, with a marked neutral predominance, the outer one displaying also an extremely thin coat of acid mucopolysaccharide with the sulfate group. The ordered arrangement of the microvilli suggests that this situation is imposed by the strong bond existing between the microvilli and the ouble mucopolysaccharide layers which would act as a cementing substance stabilizing the entire apical surface of the cell.