Premium
The Ultrastructure of the Gastrodermal Gland Cells in the Freshwater Planarian Dugesia gonocephala s.l.
Author(s) -
GarciaCorrales Pedro,
Gamo Jacinto
Publication year - 1986
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/j.1463-6395.1986.tb00848.x
Subject(s) - ultrastructure , biology , planarian , secretion , lumen (anatomy) , extracellular , microbiology and biotechnology , anatomy , endocrinology , regeneration (biology)
Light and transmission electron microscopy have been used to study the gastrodermal gland cells of the triclad Dugesia gonocephala s.l. The events involved in the ultrastructural transformation and the secretion process in these cells were followed at four different stages in both fasted and fed animals. During the feeding stage their secretory granules are directly discharged into the intestinal lumen by means of a secretion process of the holocrine type that is described in this paper. It is suggested that such secretions contribute to extracellular digestion and that disintegration of the gland cells is accompanied by a differentiation of neoblasts into new gland cells, reflecting a turnover of gland cells during the triclad digestive stages.