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KMID : 0376219860230010147
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Chonnam Medical Journal
1986 Volume.23 No. 1 p.147 ~ p.160
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An Electron Microscopic Study on the Development of the Duct in the Sweat Gland of the Fetus
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Abstract
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The development of the intraepidermal and the intradermal duct lumen of the eccrine sweat gland was studied with the electron microscope using specimens from the skin of the sole in Korean fetuses 17 to 20 weeks old, and the following results were obtained.
In the intraepidermal portion of the sweat gland duct, the site to be the lumen was first appeared within the inner cell as dense and homogeneous cytoplasmic portion in which a few vesicles and irregular membranous structures were present. Development of the duct lumen was proceeded, initial lumen bordered by the inner cell itself which provided with closely packed microvilli and contained -many vesicles, a periluminal band of tonofilaments, and a few dense bodies. When the development further advanced, intracellular small cavities thus formed appeared to unite with the intercellular lumen and completed the duct lumen extracellularly.
In the proximal portion of the intradermal duct of the sweat gland, the lumen was first formed within an inner cell similar processes to those described in a intraepidermal portion. The site to form the lumen in the inner cell appeared to have denser and homogenous area, having microvillous separation by parallel membranes in 15 nm intervals. This area was surrounded by tonofilaments. The lumen became widened by separation of intervillous space originally in the form of interdigitated clefts and pinching off the vesicles from the bordering surface membranes. No intracellular small cavities, however, was appeared in the process of the lumen formation.
In the middle portion of the intradermal duct, the formation of the lumen began with a small cleft formed by a separation of the apical intercellular spaces of the apposing two or three inner cells, and followed by intracytoplasmic invaginations at the luminal surface. Fully separated inner cells showed short luminal microvilli, a periluminal tonofilamentous zone with finely interwoven tonofilaments, and a perinuclear clear zone with mitochondria.
In the distal portion of the intradermal duct, the lumen was initially formed by separation of intercellular space of the five or more inner cells, similar to that seen in the middle portion of the duct. The lumen became widened by further separation of the intercellular spaces instead of intracellular invaginations. Inner cell contained neither vesicles nor periluminal band of tonofilaments in the apical cytoplasm.
These results suggest that the intraepidermal and intradermal duct lumen of the sweat gland are formed by a different developmental processes. And also the lumen in the various portion of the intradermal duct may have different processes in their development.
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